How To Wiki
Guide Plant Breeding Technician IT

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Adaptation Project Fields
Isolated Populations (POPs)
Crossing Block Fields
Isolated Crossing Blocks
Hand Pollination Nursery
Creating Pedigrees and Labels for Seed from Crossing Work
Seedlist Creation and Preparation of Seed for Planting (All crop nurseries)
Inbreeding Nursery
Seedlist Sample Page
Selfing Work website (See video clips at website)
Harvest and Inventory Work Outline (Inbreds and Sibs)
Harvest Work (Inbreds and Sibs)
Shelling the Inbreeding Nursery
Inventory (Data Processing)
Creating Inbred Pedigrees
Creating Inbred Pedigrees for Blends
Placing Labels on Envelopes (All crop nurseries)

Sib Nursery

Notebook Sample
Creating Pedigrees for Sib Nursery Seed

Isolated Adapting Populations (POP's)

Maize diversity in the office of Mr. N.I. Vavliov. Picture courtesy of Luigi Guarino from Suva, Fiji


The Adapting Populations are part of a long term program of adaptation that may take many decades to complete. {C}The populations are grown in small fields of less than an acre that are isolated from any other corn. They are open pollinated populations which means they are allowed to openly pollinate any other plants in the field without human intervention.

The seed is kept in the seed room in lidded, plastic ten-gallon pails labeled with masking tape and marker or in plastic burlap type bags with a tag stapled to a top corner and two stiff construction paper/cardboard strip tags in the bag.

NOTE: The POP designation on tags refers to the adapting POPulations and has nothing to do with popcorn.

The adapting populations(POPs) are the first of the corn to be planted each spring. The Yield Trials are planted shortly after or possibly after a few POPs have been planted.&nbsp {C}The POPs are planted at around 24,000 plants per acre. This is less than the usual field planting of about 29,500 plants per acre (ppa) for hybrids. Many of the Pioneer hybrids are bred for planting at around 24,500 ppa but there do exist hybrids like KWS Loft that are specifically bred for high plant population rates such as for silage/fodder and don't grow bigger cobs when the planting is at a lower rate. I have avoided using the term "plant population" in referring to the rates of planting so there will be no confusion with POP's.


  • Record in a small notebook for fieldwork the content of the planter boxes from 1-4 at the time of planting. The boxes are labeled from left to right when viewing from behind the planter. Usually Box 1 contains the early dry material and box 4 contains material that was wet at harvest time. Some other material of a related family might be added to the population in one of the boxes.
  • DANGER!!!
The following procedure exposes seed stock to possible disease contamination. You might be fired if your organization forbids removal of seed stock containers from the seed storage and/or seed preparation area. Find out what specific protocols exist for your organization. You might have to calculate and prepare an exact amount of seed in the seed preparation area before going to the field.
  • After planting, the planter boxes should be poured into a container and then spun out, shaken,tilted, and spun again to get out every kernel in the planter box. The reference to spinning refers to manually rotating the gear on the box for turning the fingers that move the seed into the planting tube where it drops into the ground.Usually this is done by removing the planter box from the planter, spinning the seed into a large cardboard box and then pouring the excess seed back into the pail or bag that it was stored in. The planter box has to be shaken and tipped in a certain way to get all the seeds out. If there is rattling when the planter box is shaken there is still seed inside. Check for seed that is stuck near the bottom of the box too.
  • When replacing the planter boxes on the planter, make sure that the box is securely fastened to the planter and that the drive gears for the planter box are engaged. On the Kinze planter, the drive gears for a planter box are connected to a flat bar with a short vertical piece on one end pointing down and a kind of curved handle 1/4 of the way from the end. The drive gears are disengaged by pulling the flat bar through, up and over the bottom of a rectangular hole in a side plate and then dropping the flat bar so that the small vertical piece falls in front of the bottom of the small rectangular hole and prevents the flat bar from moving back to its engaged position. To engage the drive gears again, the flat bar must be lifted up, and the entire flat bar and the vertical piece allowed to move back through the hole to rest in behind the metal plate.

Diseased Plants

The POP's are usually left to themselves until just before the tassels appear. Then some work of chopping out poor plants is done. It might be done earlier too.Usually this is done regarding smut.


At the time of pollination, usually nothing is done by humans but one or two very good plants might be crossed together by hand just to make sure they are crossed.


Harvest September 5 [NOTE: This date will vary according to region]

The harvest is to be done at around September 5 and maybe up to a week later. You want to do it while there are visible maturity differences in the plants and ears. It is also a means of effecting selection pressure for maturity. This date is about month from when commercial hybrids grown for grain need to be harvested. In the local region, maize needs to mature and dry down in the field by the first week of October or the producer risks being kept out of the field by snow and losses due to dropped ears are incurred over the winter.

Even though earlier maturing commercial varieties exist, many producers will accept a 1 in 5 year risk of an early frost or snowfall to obtain higher yields with late maturing varieties that make use of every bit of sunshine and dry down fast in the field. There was a time when producers cried out for a genetic solution in the form of an earlier maturing variety but it was found that many producers were planting late for various reasons and when earlier varieties were available, they were rejected because of their lower yield. The agricultural producers are paid according to the grain yield of their crop.

The producers that grow maize for silage/fodder to be fed to cattle like the late maturing, tall, exotic varieties from the equatorial regions but these cultivars have numerous problems. Some of them are just starting to reach the milk stage in early to mid October which is slightly too late for harvest. Some other varieties have a fine hair-like filament on the stalks that the cattle will not eat.

It is best to do the harvest selection when there are still visible differences between the earliest and latest maturing plants.

The harvest is done manually and involves selection work based on plant characteristics, ear quality and dryness. One population, for example, has shanks that are too long and care must be taken to take only a small number of good ears from plants with long shanks.Here is something to be researched. What are the genetics of shank length?What if the genetics of shank length are like squash weights? How do you minimize shank length in the population?

A husking pick is necessary for this work.

The harvesters should peel back the husk from good plants to see the ear quality and dryness. A good ear with lots of straight rows and a filled tip from a good plant is taken regardless of dryness. The harvested ears are taken to one end of the field and dumped in a pile. The pile is sorted by dryness into three piles of dry,medium dry and wet ears. Then the piles are sorted by ear characteristics such as length,number of rows,filled tip etc. The breeder takes about 1/4 dry ears, 1/2 medium ears and 1/4 wet ears. The ears that have the best quality and are dry may be called SELECT ears.

The husked ears are put into three bags with labels showing the POP designation,the POP name and either SELECT (dry),medium or wet. E.G. POP Antigua Select ears, POP Antigua Medium 1 of 2, POP Antigua Medium 2 of 2, POP Antigua Wet

If there is more than one bag of each dryness type, be sure to label the tag with the number of bags for that dryness and the number of the bag.

The tags are just heavy construction paper strips about 1 in. wide by 4-8 in. long. Usually they have been a dark red colour. A black, permanent ink marker was used in the field to mark the tags that were then put into the appropriate bag.


The ears are dried in the drying cupboard.

  • Make sure the ears are dried well.

They should make a kind of wooden tubular bell sound when handled together when they are dry. If the ears are not dry, the seed in the storage pail might get moldy and rot.


All of the bags for the population are brought from the storage area to the shelling area. The Select or driest ears are grouped from best to worst and a sample is taken of each ear. Then the same is done for the medium and wet ears.

Usually, the size of the sample taken from each ear has varied, although one could make a balanced bulk by counting the total number of all ears collected, dividing this number into the desired storage weight. and taking a sample of this weight from each ear.

The samples from dry ears are usually larger than from wet ears and the samples from medium ears can vary a bit depending on the ear quality. The shelling is often done with the manual sheller and the amount to be saved from each ear is poured into a container which is later stirred to mix up the seed.

The container is labelled with tape and marker and placed in the seed room.

The Isolated Adapting Maize consists of both land races for diversity in the breeding program but also heterotic groups such as B73, Lancaster, Midland, Leaming etc.

You might find it interesting to take a look at CIMMYT's photo album of Maize Landraces.

CIMMYT's Genetic Resources Use and Conservation photo album.

CIMMYT's Maize Diversity and maize relatives photo album

Tailoring for General and Specific Combining ability

After a decade of growth, it was decided that some of the populations were adapted well enough to begin taking material from them to create an inbred and to tailor the population in such a way as to encourage heterosis in hybrids produced from two inbreds from different isolated Populations. This plan interferes somewhat with the plan of adaptation to the environment.

The idea of this plan is to discover the patterns of heterosis,(general and specific combining ability) between plants from different Populations using "testers" and then to use the remnant seed of the best plants taken from a population to pollinate the entire population from which it was taken.

For example, there are two populations Leaming and Midland. Seed from a number of the best ears from each population is taken and stored as single ear seed.

The next year, this seed is crossed to some well known inbreds from a particular family like LANCASTER or B73 to test how well the population might cross to known populations with known heterotic patterns. Midland and Leaming are known to form a heterotic pattern so when crossed to plants from the Leaming Population, the plants grown from those crosses may do very well the next year. So, in the third year, the original seed from the Midland ears that made the best crosses to Leaming are planted in the Midland Population in known rows and all of the other plants or a large number of them in the population might be detasselled so the plants are pollinated by the plants that crossed well to Leaming.


This adaptation work with open pollinated material was inspired by work done by Dr. Arnel Hallauer in Iowa.

The Populations are primarily heterotic groups being maintained separately but also include landraces from other parts of the world. It should be noted that maize will not grow without the aid of man so anything that is not selected and grown in the breeding program will become extinct and the genetics will be lost. This means that maintaining genetic diversity is at cross purposes to the breeding program and is an added expense that has often been offloaded to government/public breeding programs.

The crossing of late material to early material was not producing the desired results and there were problems with photoperiodism when moving material from equatorial regions to higher latitudes so the slower adaptation approach was adopted.This is an area to be researched.

Some breeders regard these adaptation efforts as a waste of time. One could also question what exactly is happening in these fields because there is a tendency to think in terms of the discredited ideas of Lamarck and Lysenko when discussing adaptation.An example is discussions of the work done in Illinois with increasing oil and protein content in maize.Is it just a case of genetic drift or founder effect?

Isolated Crossing Blocks

These fields are grown in isolated places where there are no other cornfields in the immediate vicinity. In these fields, one male has been designated as the pollinator for all of the female plants. Usually these fields are planted with the planter but if they are small, they can be handplanted. There is no shootbagging done in these fields. Instead, all female plants are detasselled before they can produce pollen. It is very important NOT to miss detasseling a female plant and NOT leaving part of a broken tassel on a female plant where it can regrow or continue to grow and pollinate other plants. The design of these fields can vary. A general design is to plant the males every third or fourth row straight through with the rows between being the females with pathways similar to the other Nurseries. A border of male pollinators might also be used. This can take some planning and may even involve two passes over the field with the planter. Another method has been to plant the females just as for the inbreeding Nursery with paths between them and then to hand plant the males in clumps of 3 or four seeds every third row in the pathways.

Detasseling and Pollination Work

Each day, go through the rows, straight down the field and detassel female plants with tassels starting. Do not remove more than the tassel if possible. Don't remove more than one leaf with the tassel if the leaf pulls out with the tassel. If the tassel is still quite small and doesn't come out easily, try removing it the next day rather than taking out several leaves with it.. If there is a timing mismatch, cut off a bundle of tassels from males along the perimeter or any with pollen and shake them over the late females.

 *How to Detassel Corn [1]
 :: The comment regarding the teaching of ethics in schools in the above video is superfluous and should be ignored. It is also controversial because I personally learned of and witnessed quite a lot of unethical and even outright criminal activity in the agricultural industry in the late 1990's by people born in the 1940's and 1950's. I walked away from 40% ownership of a maize breeding company when my business partner  broke the last straw by keeping a sample of a Hylands Seeds maize line that did extremely well in screening tests that we conducted. 
  • Also see the Wikipedia article on Detasselling: [1]

Hand Pollination Nursery

This Nursery consists of a large number of different varieties that are to be pollinated by hand. There are several different planting designs used. These can be marked out using different coloured construction paper flags (1 in. x 8.5 in. strips stapled around the stalk) on the rows.


Designs for material that is to be crossed by hand

  • Block of male and rows of females

In this design, a block of rows (maybe 5-10 rows depending on the number of females) of a single variety is grown and designated as the male pollinators. This block is followed by single rows each containing a different variety that are designated to be females.

The Yellow Flagged rows are the designated males and the white flagged rows are the designated females to be crossed with the Yellow males.(Range row numbers run right to left in this range)

The block of males may not always be at the start of the group of females. One year, the males were planted in a four row strip on one side of the females.
When tagging the rows with coloured flags with the row# stamped on them, the male block can be given one colour and all of the females to be crossed to that male given another colour.
The basic procedure for pollinating is to take pollen from the tassels of the male block and put it on the silks of the females that follow the block of males. Several pollinations can be made with one bag of pollen similar to in the SIB Nursery.
Timing of maturity of male and female plants can be a problem in this Nursery.If the males no longer have pollen when a female has good long silks, pollen can be taken from the female to the block of males.
Both the males and the females are earbagged/shoot bagged. As much seed as possible is desired from each cross so earbag as many good plants as possible and if possible don't pollinate until there are lots of silks under the earbag. Don't trim/cut back the silks either, but make sure they are not exposed to foreign pollen.
Check the females first to see if one can be pollinated before taking pollen from the males.
After making the pollination, write on the tassel bag the Row # of the first row of the block of males, an X symbol or line below, and the row # of the female beneath, at the bottom. If in a hurry, the marking of the tassel bag can be neglected since it is a standard cross as per the design. Later a tag with the female row number will be created and put in the bag.
NB: Generic Seeds does not follow the 'Ladies First' convention when marking Tassel/Cross bags vertically in the field. The rule in the field is 'Male on Top, Female below'.
When marking TASSEL bags or CROSSING bags (tassel bags with a striped border on the faces), use your china marker to write the row number of the plant from which pollen was obtained or the first row number of the block of males from which pollen was obtained.It is not necessary to write an 'X' or the female row number since the female row number will be put on a tag which is put in a bag with the ears when the ears are harvested.

  • ===Paired rows===
These are two varieties/cultivars placed beside each other that are to be crossed together. Officially, the odd rows are male and the even rows are female but the crosses are made both ways and recorded as Odd Row number  X  even row number or later as Female X Male when written horizontally (Ladies First) or Male X Female (Male on Top) when written vertically.
These rows can be tagged with pairs of tags of the same colour alternating with at least another different colour. E.g. ROW 1 - Red Tag, Row 2 - Red Tag, Row 3 - Blue Tag, Row 4 Blue Tag, Row 5 Red Tag, Row 6 Red Tag.
Rows 1 and 2 are crossed together, Rows 3 and 4 are crossed together, Rows 5 and 6 are crossed together.

Two colours are used to show pairs of rows to be crossed together both ways. E.g. Row 1 Red flag pollen on Row 2 red flag ear and Row 2 Red flag pollen on Row 1 red flag ear.

On this side of the range more than two colours was used to mark paired rows to be crossed together based on matching flag colours.

NB: Any plant breeder, pollination labourer, or other employee of Big Yellow Seeds that marks genotype information on a tassel bag or on a diagonally-striped-border crossing bag will be reprimanded and on discovery of a second offence, will be fired as an agent of industrial espionage. It is not necessary to place genotype information on tassel bags or diagonally striped border crossing bags as this information is clearly stated in the field notebooks according to the row number, and the derivations page and stored in the database upon which the field notebook is based.
NB: There is a convention in the field of plant breeding in which the female embryo source parent is written above the male pollen parent. This convention is not followed by this company. Crosses are written vertically on the front of blank tassel bags or diagonal border crossing bags with a grease pencil (China Marker) with the row number of the pollen source above the row number of the female parent. Usually, only the row number of the pollen source is written on the front of a tassel bag in the upper third or top half of the tassel bag. Any plant breeder, pollination labourer, or other employee of Big Yellow Seeds that marks a tassel bag or diagonally-striped-border crossing bag with genotype information or the row number of the plant used as a female ABOVE the row number or genotype of the pollen source/male parent will be fired for willfull sabotage. 99% of the crosses to be made each year have been planned out in advance and the seed planted in designs that either don't involve the use of shoot bags and tassel/crossing bags or the plants in a specific row are to be hand pollinated with pollen from specifically designated rows of plants so marking the bags is unnecessary. Harvest workers are instructed and trained to be alert to the presence of miscellaneous crosses flagged by the use of diagonally-striped-border crossing bags. They are also trained in how to handle and harvest them. However, it is best to remove/harvest miscellaneous crosses prior to harvesting of the nurseries and crossing blocks.

Misc pollinations

These are unplanned pollinations that can occur anywhere in the Nursery and involve pollen taken from any Nursery. ALWAYS use the crossing bags with the diagonally-striped border when making a miscellaneous cross in any nursery or hand pollinated crossing block, especially if making such a cross in the Inbreeding Nursery. It is very important to mark the tassel bag/crossing bag with at least the correct source row of the pollen. The row number of the female can be obtained at harvest time and written on a construction paper/cardboard strip tag with a permanent ink marker and put in the harvest mesh bag with the ears.

Crossing Block and Misc. Cross Pedigrees

These crossed pedigree updates have been the most difficult to deal with primarily because of formatting and identification problems. {C}The pedigrees of the parents used for crosses are not changed. They are just put together with an x or an asterisk (*) between them.

NOTE:The use of an asterisk in place of 'x' is not generally accepted procedure and might be confused with the use of '*' for backcrosses in Purdy pedigree notation.

NB: When writing pedigrees, Generic Seeds follows the 'Ladies First' convention only when writing a pedigree horizontally. When writing a pedigree vertically, the rule is ALWAYS 'Male on top, Female below'. This corresponds with the spatial location on the plant of the male and female inflorescences (tassel and ear).

For notebooks (horizontal pedigrees), the female is listed first, followed by the male on the same notebook row.

E.g. Female: Lan5, Male: B73,
Cross in book: Lan5 x B73 or Lan5/B73

NOTE: Use of '*' in place of 'x' conflicts with Purdy Notation and should be abandoned

For labels (usually written vertically), the Male is on top, the female is below with a horizontal line between male and female.

A pedigree written vertically

The label format is not a real problem if the male and female pedigrees are in separate columns that can be designated as fields for a database list. Printing the pedigree is then done using the fields.

Eg. Center text of male and female field cells, print female source row field or field value in top left corner, move over and print the current year in the top right corner, go down several lines and center, print male pedigree field,go down one line, print horizontal line, go down one line, center and print female pedigree field. Do next row in list
All of the information on both male and female should be kept but the row can be hard to read with so much data on it.

For topcrosses, the female row number can be used to find seed. This can also be done for misc crosses and hand pollinated rows but care should be taken to distinguish between different males crossed to the same female pedigree. The pedigrees on the abbreviation list and nursery or crossing block the cross was made in, can be used to figure this out. Usually, the envelopes will have the cross on them in marker by row number. {C}Identification problem: If the pedigree gets too long especially for inbreds, the cross is given a new designation.

E.g. R8W = (CO264 x KE833) * (CM220 x CM109*CM169)/(KE404 x W821) * (CM220 x CM105)

R8W pedigree written vertically

This was an eight way cross involving a female ((CO264 x KE833)*(CM220 x CM109*CM169)) and a male ((KE404 x W821)*(CM220 x CM105)). The male pedigree shows that it was made by first making two crosses and then crossing them together. That's 3 crosses to make the male.The asterisk is used to show that the pedigrees are from different plants. The female was made by first crossing CM 220 to CM109 and CO264 to KE833. Then the plant with the pedigree of CM220 x CM109 was pollinated by CM169 to make a new cross. The next year the two plants of CO264 x KE833 and CM220 x CM109*CM169 were crossed together. That's 4 crosses to make the female. Crossing the male to the female makes this an eight way cross. This explanation might be completely incorrect. R8W might just be a synthetic made by putting 9 parents in the same field and letting them cross pollinate.

Other examples of new designations:

FB 249 = CM249 x F2 x CM 249
B73B = B252 x B73

The seed is usually labeled without the new designation so the seed for a new designation on a seedlist must be found using source row numbers or some kind of index sheet showing new designations with full pedigrees and sources. {C}The breeder prefers that new designations carry some information about the parents.

E.g. PCB51 retains part of the pedigrees for Pioneer x CB51
LF833 = KE833 x Longfellow
AJA264 = CO264 x JA16 x A641

{C}All inbreds at S5 are considered pure and should be given a new designation. For related material the designation can be in order.

E.g. CSK20 = SK380-4-3-10-1-2
CSK21 = SK380-4-4-6-1-1
CSK22 = SK380-6-1-4-1-1
CSK23 = SK385-3-2-3-1-1
CSK24 = SK113-1-2-2-1-1
CSK25 = SK113-1-3-4-1-1

Countries have reserved pedigree designations.

Eg. Canadian government Research Station pedigrees consist of the country identifier C for Canada followed by the location of the research station that made the inbred.

  • Ottawa = O
  • Guelph = G
  • Lethbridge = L
  • Brandon = B
  • Morden = M
E.g. CO418 is from Ottawa, CL30 is from Lethbridge, CM105 is from Morden, CG Lancaster is from Guelph, CB3 is from Brandon.
E.g. B= Iowa (because there are other U.S. states that start with the letter 'I'.
Mo = Missouri (Mo17)
W= Wisconsin (W153)
Corporate Designation: Usally P is Pioneer as in P3979, P3984 or P651
Note: DK can stand for Dekalb but some of the older pedigrees have phenotype information in them such as OP for open pollinated and DK for deep kernel.

Formatting problems: Getting the pedigrees and all related information together beside each other is easy for topcrosses but harder for hand pollinated crossing blocks with paired rows and male blocks. Topcrosses use the same male on all females so the male pedigree and source information can be copied in a column beside the females. A column of x's can be inserted between them.

Then, new designations can be assigned to the new crosses in a column to the left of the females. A similar procedure can be used for male blocks followed by females in hand pollinated crossing blocks.

Paired rows in a hand crossing block must be placed beside each other. A simple method would be to copy the list and place the copy to the right of the original list but offset one row up. It is assumed for this that a distinction is not being made regarding which row of the pair was male or female. However, formatting protocol will assume for all seed from the same pair of rows that the female is on the left.

Miscellaneous Crosses were the worst to deal with. All miscellaneous crosses were recorded as row number x rownumber in the notebook on blank pages at the end of the Inbreeding nursery . Often on the back of the last few pages of the Inbreeding Nursery.

The best way used to get the pedigrees side by side was to work with two filtered database lists using source row numbers to select each parent (and all its information) of the crossed pair out of the notebook list.

Insufficient male seed for topcrosses

Sometimes there is not enough seed of a particular male to pollinate all the females in a crossing block so seed has been added from closely related plants to the stock of seed used as the male. Since, there is more than one male pedigree, use either the pedigree of most of the seed or use a pedigree that would fit both by finding common pedigree info. E.g. If B73-5-1-1 and B73-5-1-2 are used for the male seed, the pedigree of the male used for labels could be B73-5-1-(1,2). It is a blend of cobs 1 and 2. If most of the seed is from B73-5-1-1, that pedigree could also be used as the male.

NOTE: The notation used for a blend (mix of related inbreds) was very idiosyncratic. It was denoted by using a round bracket containing the related pedigrees. A comma was used to separate noncontiguous values while a dash was used to denote a mix of contiguous pedigrees). E.g. Mixing inbred B73-1 and B73-3 would be denoted as B73-(1,3). Mixing B73-2 and B73-4 would be denoted as B73-(2,4). Mixing B73-1,B73-2 and B73-3 would be denoted B73-(1-3). If all of the inbredsthat differed by only the last number were mixed, it was denoted as B73-Bulk.

Technically, mixing the seed like this is not good because one does not know exactly, what was crossed to what. However, if testing for performance by family it can be ok.

NB: There doesn't seem to be much standardization regarding maize pedigree notation.I started using '*' in place of 'x' but this violates the Purdy notation used by small grains breeders (wheat etc.). Cimmyt appears to have used a modified Purdy system at least for the International Crop Information System (ICIS).In the Purdy system, a cross is denoted with a forward slash '/' rather than with 'x'. So (A x B) old notation = (A/B) Purdy.A second cross is shown with two forward slashes (//) and each additional cross is shown by placing the cross number between the slashes (/n/).

A x B = A/B
(A x B) x C = (A/B//C)
(A x B) x (C x D) = A/B//C/D
[(A x B) x C] x D = A/B//C/3/D

A backcross is shown using '*' and the number of times the specified parent was backcrossed. ((A x B) x B) = (A/2*B)

[(A x B) x B] x B = A/3*B

Regarding the Direction of a Cross

The standard procedure has been to differentiate between crosses pollinated by one variety as the male and the other as the female and vice versa. AxB is considered a different cross than BxA.The female is always the first parent listed horizontally.

Reciprocal crosses should be the same except when sex-linked traits are involved or when considering traits that involve extranuclear material such as cytoplasm or the mitochondrial and chloroplast organelles and their genomes. If the traits involve only nuclear DNA, it doesn't matter much which variety was male or female. See Maternal Inheritance and Xenia at

Seed Preparation

January - March

Selection Work and preparation of seed for planting

There may be a number of other tasks running concurrently from January to March but the main work is the selection of material to grow in the spring and preparation of seed for planting.

Selection work - General

The basic task at this time of year is to work from the Inventories to select the material that is to be prepared for planting and to print out the Seedlists. Often the Bean Nursery has been prepared first followed by the Isolated Crossing Blocks and GENERIC SEEDS Maize Yield Trials because these can be large and involve more seed counting and other work. Even though the Cereals are planted first, they are usually prepared last because often there are few changes to be made between the Inventory and Seedlist. All of the seedlists are open for additions and changes right up until a week or so after planting.
If a single database is being used to store the data for all seed in the storage room, there should be some indication in each database record regarding the Nursery the seed came from and the year that the seed was harvested. This is because much of what is planted the next season in a specific nursery is drawn from the previous year's inventory of that same nursery. It is rare to include material from 2 or more years previously or from another nursery.
The Seedlists are printed as 8.5 x 11 portrait size.


Manual Counting

You need 2 corners cut from the top of a cardboard shoe box. They should have two sides that meet at a corner. Pour an amount of seed from the appropriate storage envelope into one corner piece. Slide the other corner piece under the first so the back edge is twice as long as for one piece and the open side is closest to you. Use a pointer of some kind, like a sharp pencil, to separate 2 or three seeds from the others. Move these seeds using the pencil in a horizontal sweeping motion to the other corner,counting by 2's or threes. Continue transferring seed from the one side to the other until you have 50 seeds in the other corner. Use the sides of the corner piece to help pour the 50 seeds into one of the empty envelopes. Repeat for the second envelope and then put any remnant seed back in the storage envelope. Put the storage envelope away and then put the newly filled envelopes in the small white trays.

Using a Balance to Count

The balance is for weights of less than 1 kg and will have a unit counting feature. See the instructions for use of the balance regarding how to proceed. Use a small pan rather than a large one. Remember to always tare out the pan's weight so you can work just with the weight of seed or unit count.
First, prepare the balance to take an average seed weight. This can be based on 5,10 or 20 seeds depending on the accuracy desired. Use the 10 or 20 seed average. If using the 20 seed average, count out 20 seeds into the pan and begin according to the instructions. The unit count should say 20 and adding one or two more should increase it by one or two units. Add more seed until you have 50 units, pour the 50 units into one of the empty envelopes. Pour 50 more units from the storage envelope into the pan and then pour these 50 units into the second empty envelope. Put the 2 newly filled envelopes into the small white tray and return the storage envelope to its proper place in the storage tray.
Since seed of different varieties will have different sizes and weights, the averaging procedure will have to be done for each new variety of seed. This means everytime the pedigree changes.

Rough and Ready Count

For certain nurseries, such as the Maize Inbreeding Nursery that will be overplanted and thinned at a later date, it is acceptable to measure out seed quantities by sight only. The point is that this can be done where the number of plants in a row or plot is not important. Only about 10 good plants are wanted in each row of the Maize Inbreeding Nursery but 15-20 seeds are planted. 20 seeds can be placed in the palm to get an idea of the amount and then a similar amount is poured into the palm of one hand each time seed is needed. The seed is then poured from the palm into the envelope with the correct row #.

{C}Modern Seed Counting Equipment

See Seed-counting machine
Some modern seed counting equipment can be seen here from Midco

Choosing material to plant


The POPULATIONS are the first of the Maize to be planted. Usually, before and then after the Yield Trials are planted. They are planted in small isolated fields. No formal Seedlist is made for the POPULATIONS. One can make a list of the populations in the Seed Storage Room and consult with the breeder regarding which are likely to be planted and where. Eventually, the name of the Population and the location it was actually planted at is recorded in the field notebook at the time it is planted. The field notebook should also state the planter buckets in which different categories of seed such as dry, medium, wet or new seed were placed at startup. The planter buckets are numbered from 1 to 4 from left to right as viewed from behind the planter.


The Isolated Crossing Blocks Seedlists will consist of lists of Inbreds and material from other Nurseries that will be designated as females. The list is of single rows. One female per row. The format is basically that of the Inbred records. i.e. ROW#,Family,Pedigree,Source Row year. For the source row year column heading put the year last below Source Row as in Source Row 1999. That way the year is closest to the data if the top line should get missed or printed out on a line on the previous page. Note that the row #'s 1-2999 are reserved for the Inbreeding Nursery and rows 7001-8999 are reserved for the SIB Nursery . Always start with a number that ends in 1. E.g. 3001 or 9501. The male might not be designated until much later but a space should be provided at the top of the Seedlist to specify the male. Usually the Crossing Block is named for the Family of the male. If the male is a Stiff Stalk, it will be the Stiff Stalk Crossing Block.
Since the seed for crossing blocks can come from any Nursery or year, there can be several columns needed for source rows from different years of just the Inbreeding Nursery and then seed from other Nurseries will have to be specified somehow. The majority of the Inbreds will be taken from the previous year. It should be sufficient to print only that year's column for those Inbreds. If needed, the year before that can be printed too. If more than 2 columns are needed because some seed is from 3 or more years previously, the additional columns can be added in the computer version but printed out only for the pages where it is needed. This may be a bit of trouble for formatting the printing but is worth it in the number of pages that have letters that are big and easily read and not cramped together with a large blank area on the right.
A Crossing Block might not be planted if space cannot be found for it.
Seed Preparation
Same as for other Nurseries. Pay careful attention to the Source row # as a clue to the Source Nursery. Make very sure the correct year of the source is used.


Based primarily on the previous year's Inventory of the Maize Inbreeding Nursery. Use single row #'s. Reserved row#'s for this Nursery are 1-2999. Seedlist format matches Inbred records except only one Source row column should be shown on the print out where possible. Two columns are acceptable if there is not enough seed and seed from 2 years previous is used instead. The rule is to keep the number of columns small so that errors are not made by reading the wrong column. Add additional source row columns where necessary but print them only where these columns are used. Note that the breeder may also want a SEED REMARKS column.
Seed Prep
  • 20 seeds per row. Can use manual count or rough and ready.
  • Don't completely empty a Storage envelope. Keep some seed (about 5 seeds at least) in case there are planting problems or any other problem that may result in the loss of the row to be planted.\
  • Write down or indicate on the Seedlist the source of seed if not enough seed was available and seed from a different source was used.


Usually this Seedlist is based on the previous year's Inventory.
NOTE: There are seedlist formatting differences regarding Row#'s. The column(s) for Row#'s must be large enough to hand write four digit numbers on two sides of a dash.E.g. 7001 - 7010. The dash can be put in by computer. The breeder has prepared the seed for this Nursery himself. He will specify blocks of 5,10,15 or 20 rows. Update the computer when the Seed prep for this Nursery is finished.
Check that there are no overlapping numbers E.g. 7001-7010,7010-7015. Should be 7001-7010,7011-7015

Seed prep

The breeder has usually used a rough and ready count of around 40-50 seeds per row. The blocks of rows are of seed from the same storage envelope. Watch out for misplaced planting envelopes out of row# sequence in the small white trays. The breeder has to also be careful to fill only what he records and not fill envelopes from another group with seed from the previous group. Where there are doubts about the order of the envelopes and their contents, set out several pans to look at the seed in the envelopes just before and after a change of blocks. Put the filled numbered envelopes of seed in the pans. One envelope per pan. Put the pans in order according to the numbers on the envelopes. Pour out the seed from each numbered envelope into its pan and leave the numbered envelope in the same pan with its seed. Consult the Seedlist regarding where the blocks change and compare the seed in the pans. It may also be necessary to have two pans holding the storage envelopes and their seed as well. If there is no error, the seed in each block should be similar to the source block storage envelope seed. The change of blocks should be very apparent and also correspond to the Seedlist row#'s. I.e. If the first block is from 7001-7010, row 7010 should have seed similar to all of the previous rows and seed from row# 7011 should look different. Row 7011 should match the seed from the source block storage envelope for the next block of seed.


The seedlist for this crossing block can end up being revised several times. It is never closed until all the seed that the breeder wants to plant is in the ground. The entire hand crossing block may be planted by hand or just the straggler rows of seed received after machine planting. Seed is primarily inbreds and can be prepared ahead of time but often lots of additions are made later as space availability is better known. This seedlist can get tedious to make because there will be blocks of males where the male pedigree must be shown for each row of the block followed by a list of single row females and then paired rows where a different male may appear many times between different females. There is more moving of records around for this Crossing Block.

Miscellaneous Comment

In 1999, a first attempt was made without prior notice to select material for inclusion in Crossing Blocks using MS-Access. Microsoft Office was not offered to the company when the computer was purchased and the attempt to procure it at that time was beyond budget. Only Excel was purchased since the ability to update the pedigrees and to use the macros was more important. The database bundled with the computer was MS-Works. Inventory files were saved for each separate Nursery in Ms-Works database form. Selections were made previously from printed Inventory lists of separate Nurseries.
The attempt to use Access was a good idea but should have been done with more planning. As a result, the databases for the different Nuseries had to be merged and then Access had troubles due to formatting differences not only between Nurseries but also of columns as numbers or text. The Source Year and row number column for example, contains both text and numbers.

Inbreeding Nursery


The Inbreeding Nursery seedlist can be created at any time after the inventory work for the previous year is finished. Usually it was created a few months before planting. It is created with the knowledge that there may be some unanticipated additions closer to planting time and additional space allotted.

The seed is prepared for planting according to the seedlist.

A 2-range Inbreeding Nursery

This illustration is of a hypothetical 2-range Inbreeding Nursery of 80 one-row plots. Usually there are more than a dozen ranges for around 1200-1500 one-row plots.

The nursery is staked with numbered wooden stakes every fifth plot, and the side plots if they are not multiples of five.

The four guard rows on each side of the Inbreeding Nursery are not strictly necessary. They might reduce wind damage and obscure visibility from nearby roadways. They could be replaced with pathways wiide enough for a pickup truck or tractor. The pathway can be seeded to a green manure/covercrop and maintained with a fieldmower.

A row spacimg of 30 in. (0.76 m) was used but a narrower spacing such as 22 in. is not recommended as it makes it difficult to maneuver around the plants at pollination time. A 36 in. or 40 in. row spacing allows more room to move but may involve other problems such as planter reconfiguration delays or tractor wheel spacing and implement configuration problems. Having a planter with a row spacing designated solely to the Inbreeding Nursery would be one possibility if the yield trials or other nurseries/fields are being planted at a different row spacing.

Inbreeding Nursery Seedlist Sample Page


Inbreeding Nursery Seedlist

Planting Plan

An abstract Planting Plan is created on a spreadsheet. It is used to fill planting trays and either a copy or the original is inserted near the front of the Inbreeding Nursery Notebook for that year to act as a handy map.

The planting plan should have a centered header that states the name of the nursery, the type of document and the year. E.g. Inbreeding Nursery, Plantimg Plan, 2013.

On the extreme left there should be a column showing the Range numbers. The numbers should decrease going down the page.

Plot numbers are shown on the left amd right sides of arrows that alternate direction in a serpentine fashion. These are all one-row plots and are the plot numbers on each side of each rrange.The plot numbers should be in individual columns but positioned so that they are close to the ends of the arrows. The direction of the first range may vary depending on where the field entrance is or the location of the Inbreeding Nursery in the field.

Make sure that the arrow column is wide enough to show all arrowheads.

Also, make sure the arrows alternate in a serpentine pattern from the first range to the last range.

Planting the Inbreeding Nursery

  Much of this information can be found on the Maize Yield Trials page.

Add link to section

Inbreeding Nursery Notebook

Inbreeding Nursery Notebook Covers


Inbreeding Nursery Sample Notebook Page

to be added
The usual column headings were Row, Family, Pedigree, Source Year Row Number (Source Year as column heading with that year's row number as the column entry), Vigor (Vig), Days to 50% Tassel (Tas), Days to 50% Silk (Slk), Ear Height (EarHt), Plant Height (PlantHt), Number of cobs collected (Cobs), Weight in grams of Bulk sample collected(Blk), Remarks (wide column).
A lot of the columns after the Source Year and row column were not used so that it seemed a bit useless to have them on the notebook page. At one time the plant height and ear height of inbreds was entered because it can be used in predicting the plant and ear heights of hybrids involving the inbred. Often this data wasn't used so Generic Seeds abandoned the collection of this data partly to alleviate the workload.

a list of data one could collect that could be used as column headings.

Insect Reactions Aphids grade1-5 Corn Earworm grade 1-5 European Corn Borer 1st Broodgrade 1-92nd Broodno. larvae/plt (plant,shank,stalk) Corn RootwormNorthern grade 1-9 Root Damage grade 1-3Root Regeneration grade 1-5 WesternRoot Damage grade 1-9Recovery grade 1-9Tolerance grade 1-9 Chemical Analyses Oil (Grain) Quantity%
Disease Reactions Unit of Measure
Leaf BlightH. carbonumRace I R or SH. maydisRace O grade 1-5
Race T grade 1-5
H. turcicum grade 1-5
Phyllostica (Yellow leaf blight) grade 1-5
Kabatiella zeae (Eyespot) grade 1-5
Stalk Rot diplodiaInternode Intensity grade 1-5
Vertical Spread no. nodes
Stalk Rot Gibberella Internode Intensity grade 1-5
Vertical Spread no. nodes
Ear Rot grade 1-5
Kernel Rot grade 1-5
Smut %
Maize Dwarf Mosaic grade 1-9
Downy Mildew % infected plants
Rust %
Characters Evaluated
Planting to 50% Silk (Silk) days

Planting to 50% Pollen (Tassel) days

  • 1 - Good **1 - Upright

5 - Poor 2 - Intermediate 3 - flat ==

Agronomic Characters Unit of Measure
Planting to 50% silk (Silk) days
Planting to 50% pollen (Tassel) daysUniform Evaluation Tests - Corn Inbred Lines Agronomic characters Unit of measure
Height of plant cm
Height of ear cm
Ear Height Ratio no.
Tassel Primary Branches no.
Root lodging %
Stalk lodging %
Root pulling strength kg
Root Strength rating grade 1-9
Stalk Quality
Crushing strength kg
Rind Thickness cm
Wt. 2" section gm
Cob quality
Crushing strength lbs
Weight 2" Section gm
Yield (grain) kg/ha
Shelling % %
Ears per plant no.
Planting to maturity (Physiological) days
Grain Moisture at Harvest %
Dropped Ears %
Ear Length cm
1000 Kernel weight gm
Test weight kg
Row No. no.
Husk covering grade 1-5*
Leaf Attitude grade 1-3**
SOURCE: North regional Research Publication No. 213
Report of Uniform Evaluation Tests - Corn Inbred Lines
Sponsored by North Central Corn Breeding Research Committee NCR-2
Summarized by Lee Mason and M.S. Zuber
Unknown date of publication (Data of Uniform Evaluation Tests 1970-1971)
A more modern list of over sixty phenotypic traits of maize can can be found at the Buckler Lab for Maize Genetics and Diversity ( website.

Inbreeding Nursery Innoculation

A practice that was abandoned was that of inoculating the plants by striking the stalks with a nail sticking out from a stick. The purpose of this was to injure the plant and make it more susceptible to disease. It is also possible to induce diseases in the plants by soaking pipe cleaners in a solution containing a disease and inserting the pipe cleaners into the holes made by the nail. Dr. Jugenheimer has some pictures of inoculators and a few more details about this in his various editions.

Holden back the Ears



  • Pollination Pouches
  • Black China Markers (cut in half) also known as grease pencils
  • Lawson Bags #218 Shootbags (Earbags )
  • Lawson Bags #402 Tassel Bags
  • Plier type Staplers
  • Staples (1/4" mostly and 3/8" occasionally)
  • small knife

Avoid sunburns and heatstroke by dressing appropriately. Wear a hat of some type possibly with protection for the neck from sunburn. Straw hats work well. Baseball caps can leave one with a very red neck.


Don't get dehydrated. Take water to the field. Don't take ice water. The water can be cool but not cold. Don't drink too much water.

Pollination Aprons

Must hold all of the equipment listed above. {C}A deep pouch for the #402 Tassel bags (on the left side) that must be deep and wide enough to hold a notebook(10x 12?). {C}A Shallow pouch for the #218 earbags (on the right side)(6 inches deep?) {C}A shallow pouch in the middle for a box of staples, 2 China markers ( in case one is lost) and the small knife. {C}A holster for the staple gun that is easily reached with one hand. My staple gun was always falling out of the shallow pouch and was hard to get to in the deep pouch.

The pollinating apron is best made from a tough material like Denim with tough thread. {C}Automobile seatbelts make a very easy to attach belt that can be adjusted for a person's size.

Some workers use a vest type of garment rather than an apron.

Maize Reproductive Parts

How to Pollinate Corn A YouTube video by Mycogen Seeds

Also see the YouTube videos "Corn Crossing Tools" and Pollination Methods: Corn

NOTE: In the YouTube video, Pollination Methods: Corn, the tassel bags are marked with a vertical designation with the female genotype listed first on the top. This is contrary to the method used by Big Yellow Seeds in which the row number of the pollen source (male) is marked on the top and the female row number is usually not marked on the crossingbag/tassel bag unless the cross is done outside of a designated crossing block such as in the Inbreeding Nursery. If the row number of the female plant is put on the crossing bag/tassel bag it is placed below the row number of the pollen source and below an 'x' or a line. The female row number is usually obtained from the row tag placed in a harvest bag of cobs harvested from the row since the crossing blocks have been designed so that all crosses made in a row are the same. The pedigrees/genotypes are obtained from the row numbers after harvest. I have referred to crossing bags/tassel bags because when a cross is made outside a crossing block, such as in the inbreeding nursery, a specially marked bag (crossing bag) is used to distinguish the cross from selfed plants. Crossing bags usually have a very easy to see diagonally striped border on them whereas the tassel bags are blank.

China Markers

Cut them in half and give each person two china markers. The one half is harder to peel but smaller china markers are easier to use than full length markers

Marking the date on the Tassel bags

Put the tassel bags in the deep pouch with the open end near the bottom and the seams away from you. Bend the tops of the bags over (away from you) and mark the day of the month on the upper right corner of the first bag. Flip through the bags one at a time using the thumb and mark each bag until all of them are marked.

Generic Seeds did almost all of its pollination work between about the second week of July and the first week of August, so there wasn't confusion when just using the day of the month. Other researchers have longer pollination periods and need to distinguish June 7, from August 7 or even September 7, so they may use a binary or other type of marking system. See the maizegdb website Controlled Pollinations of Maize, Section 6, "Dating the Tassel Bags".


NEED TO BE DURABLE (preferably metal) and WORK IN A DUSTY, DIRTY ENVIRONMENT The mechanism should be simple so it's easily fixed if jammed with dirt or pollen

Shoot bags/Earbags

Shootbagging procedures in the Inbreeding Nursery

Note The correct words to use are "shoot bagging". I got into a bad habit of referring to a shoot bag as an ear bag. This just causes confusion when the shoot bag is removed at pollination time and the tassel bag is placed over the ear and stapled around the stalk.

When to shootbag/earbag (time of year,maturity of plant,growth of earshoots,time of day)

When to earbag depends on the maturity of the plant. In the local area, most plants are starting to make earshoots in the second week of July. You just have to periodically make checks for earshoots from the start of July.
Early morning isn't good for shootbagging because everyone ends up getting drenched with water from the plants as they move through the field. Evening is best or anytime that pollinations are not being done.

Where to shootbag/earbag (top earshoot)

You want to get the top earshoot of the plant. It will appear as a small triangle between leaf and stalk where the leaf attaches to the stalk. Wait until it is a good 1/2 inch or more long before shootbagging it.
Sometimes the second earshoot from the top grows first, so check before knocking off the leaf.

(The practice of knocking off the leaf limits the ability of the plant to use the leaf for photosynthesis, so this isn't considered a best practice and in the Maize GDB video you will see that the shootbag/earbag is placed without removing the leaf.)

Creasing the shootbag/earbags and expanding the creased sides

The shootbag/earbags have one side longer than the other. Put the long side in front with the short side closest to you with the opening at the bottom. Using the forefingers and thumbs, bend the long side up so it is even with the short side and crease it. Then using the forefingers inserted up into the bag, flatten the side creases so the bag is recrangular. Blowing into the bag will also work.
Knock off the leaf with a sharp downward motion of the hand.

The doubled side of the earbag is then placed against the stalk with the earshoot between the doubled side and the short side. Then pull straight down over the earshoot, cutting into the stalk just a bit.

Putting the shootbag/earbags over the earshoot

Forefinger up as far as possible along the inside of each side with thumbs on the side outside the bag. Pull straight down over the earshoot and into the stalk maybe a half inch or so. It should not be tight against the stalk. Lift it up a bit if it is. The shootbag needs to rise with the cob as the cob grows longer and not be snagged on the cut of the stalk.

Problems with droopy shootbag/earbags

The reason for flattening out the side creases is because when the crease is there, the sides do not prevent the bag from drooping and the earshoot often will tear the shootbag at the droop and grow through the shootbag.


Marking the date on the Tassel bags {C}As above

Pollinations (SELFING) in the Inbreeding Nursery are made by collecting pollen from the tassel of a single plant and applying that pollen to the silks of the shootbagged top earshoot of the same plant. The exact same tassel bag that was used to collect the pollen is then slid over the pollinated ear. Give the tassel bag a sharp snap holding each end to help the pollination by spreading pollen inside that sticks to the bag.

When to make pollinations

The silk should be like a good small paint brush and about 2 inches long or so.

Also, there needs to be enough pollen. If you can see the pollen in the bag, that is actually far more than needed. It should be yellow. {C}Pollination is best made after about 10:00 a.m. and before 1:00 p.m.

When to start pollinations each day

Usually around 9:00 or 10:00. Tap an inbred tassel across the palm of the hand. If pollen appears on the hand, pollination of the nursery can start.

When to end pollinations each day

Pollen is adversely affected by heat and the silks by lack of moisture. It is best to stop pollinating after 2:00 p.m or 3:00 p.m.

Contamination issues in the Inbreeding Nursery

In general (outbreeding, tassel bags not put on tassels)
A risk is taken by the breeder by not placing tassel bags over the tassels and by not being strict about sterilizing pollen on hands after pollinating an inbred.
This risk is considered acceptable since any outcrosses produced are hybrids that are easily distinguished by their higher height in the inbred field and can be cut out of the field.

use of hands

Get into a habit of using one hand for shaking the tassel and the other for trimming silks and helping apply the pollen to the silks.
Note: If tassel bags have been put up the day before, shake the bag and remove it carefully so the pollen does not fall out
Make a pollen applicator with a handle and spout by folding back part of the upper side.
Use a small knife to cut the silks back. The is a good illustration of this by an intern at Cornell. However, at Cornell, the cut is severe and requires a one day delay for the soilks to grow back before the silks can be pollinated. The blog is Promiscuous Corn ( )
Note: There are some inbreds with very tight husks or long husks which are helped to pollinate by cutting back the silks. This is not a trait the breeder wants to encourage.
The thumbnail of the uncontaminated hand can be used to trim the silks so they are only about two inches long but this method probably would not be acceptable at Cornell because of the possibility of contamination..
The same hand can encircle the cob without touching it and the applicator spout can be tapped against the inside of the thumb so that pollen falls on the silks

jostling plants nearby

When working around an inbred be very careful not to jostle a nearby plant as this may result in the plant shedding pollen that blows in the wind and can contaminate exposed silks.

Not enough pollen (contaminated bag )

If the tassel is shaken for pollen but there is not enough pollen to make a pollination or the silk is not yet ready to be pollinated, the bag is considered contaminated. Shake it out onto the ground and place it upside down inside the long pouch but on the side closest to you where it will not be picked out.

Contaminated bags are collected together and used the next day or the day after.

Making Pollinations
Stand to one side and in front of the plant. Grab the plant with one hand below the base of the tassel or at the base of the tassel. Carefully bend the tassel into the tassel bag that is being held with your other hand in front of the plant. The bend should be wide rather than sharp and involve part of the plant below the tassel. You don't want to break the tassel off because if there is not enough pollen, a broken tassel can't be used to make a second try. Shake the tassel vigourously against the sides of the tassel bag. Five or six times should be lots.

How to carry the tassel bag

Don't let pollen fall into the bag while searching for a plant to pollinate. Carry it by placing it over a fist without pollen on it and holding the forearm up at a right angle to the bicep.

Creating a pollen applicator from the tassel bag

First, pull up on the top side and down on the bottom side (with the seam) at the same time. Make a crease on the bottom side. Then fold the topside from about the middle to make a handle with only a small opening near the bottom.
If the amount of pollen is small, gently tap the bag until you can see pollen in the bottom crease and slowly tilt the bag and tap the pollen closer to the opening.
A video and a do-it-yourself exercise might better explain what is being talked about here.

Missed first ears

Try very hard to shootbag and pollinate the first ear. However, if the first ear is missed, shootbag the second ear and later at pollination time, tear the first ear off the plant and pollinate the second ear.

Stapling the tassel bags

The tassel bags are stapled by bringing the two corners of the bottom back side together around the stalk and stapling near the bottom. Don't staple the bag tightly to the stalk but allow some room for growth.
If the cob is long, staple the tassel bag on the bottom edges near the cob but not tightly to the cob. Staple also farther from the cob, near the edges of the tassel bag in case the first pair of staples is too close.

Adjusting bags for growth

After pollination, periodically check for cobs trying to grow out of a bag or bags that have popped their staples or are too tight. The bag can be pulled up and down the stalk as needed.
  • Watch for possible contamination problems after tassel bag is put on
  • Watch for bags with holes chewed into them by bugs that have allowed the silks to be contaminated. These ears must be discarded immediately.
  • Some good pictures related to maize pollination may be found as part of the genetic research activity, 'Plant Breeding and Predicting Offspring Traits' By Patty Hain - at
There are good pictures there of the tassel bags, ear shoot bags, tassel bags over the tassels and ear shoot bags over the ear shoots.
: African Journal of Agricultural Research
Viability of maize pollen grains in vitro collected at different times of the day


Kaian Albino Corazza Kaefer1, Ricardo Chiapetti2, Luciana Fogaça2, Alexandre Luis Muller2, Guilherme Borghetti Calixto2 and Elisiane Inês Dall’ólglio Chaves2 1State University of West Paraná - UNIOESTE, Marechal Cândido Rondon – Paraná – Brazil, Street Pernambuco, Number 1777, Zip Code: 85960-000, Box: 91, Center, Brazil. 2Pontifical Catholic University of Paraná - PUCPR, Toledo – Paraná – Brazil, Avenue União, Number 500, Zip Code: 85902-532, Center, Brazil. Received 18 July, 2015; Accepted 17 February, 2016

Vol. 11(12), pp. 10401047, 24 March, 2016 DOI: 10.5897/AJAR2015.10181 Article Number: F307D4157688 ISSN 1991637X Copyright ©2016 Author(s) retain the copyright of this article

{C}Some of the differences in the procedures are due to differences in the perception of risk of contamination. A University researcher is usually doing work in genetics that can’t tolerate any risk of contamination at all. Not bagging the inbred tassels saves time and money and the risk of contamination is small and contamination is easily detected. In the SIB nursery bagging tassels might be a good idea.

You may want to adopt some of the procedures, but think carefully before doing so. Tearing the earbag top off is fine if there is no doubt that there is enough silk to pollinate. Pulling the earbag off instead, allows one to put it back on if there is a problem. One must also be very careful about bending the inbreds as they are often brittle and will snap off if bent from behind.

An oddity I noticed about Generic Seeds was that tassel bags were never placed over the tassels the day before pollinations in any of the nurseries. One should think this increased the chances of contamination and yet there didn't appear to be any contamination in the Sibbing Nursery.

Be wary of letting an advanced degree go to your head. One can deceive oneself into believing one can handle certain risks which blow up into major errors.

A researcher with a Ph.D. who did studies as a student on proper distances to avoid contamination from foreign pollen, contaminated his own breeder's seed field of a new cultivar by planting other maize within twenty feet. This error caused foundation seed growers a lot of unanticipated expense roguing offtypes from the fields. The plant breeder may have thought he could handle the extreme closeness, believing that the cultivar would pollinate at a different time than the other maize. Never gamble with mother nature!

Another faux pas not immune to certification or advanced degrees is planting evaluation trials in a low part of a field which has poor surface and/or poor subsurface drainage. There is a reason the agricultural producer is only too glad to part with this nuisance area and get rent money for it at the same time.

Inbreeding Nursery Harvest Work


  • Preliminary work
  • Tagging rows
  • Creation of tags
  • Harvest of selfed cobs
  • Harvest of Sib cobs
  • Harvest of crossed cobs
  • Collecting cobs in harvest bags
  • Shelling
  • Data Entry
  • Pedigree creation
  • Labels
  • Shipping and Storage
  • Fall Tillage Field Work

{C}Inbreeding Nursery Harvest work

In the Field


Tag the first plant in all rows with consecutively numbered heavy construction paper stapled around the stalk. The tags should be of a designated colour for the inbreeding nursery to make it easier to identify inbred ears when removing material from the drying cupboard. Light blue shows up very well in the red mesh bags as does yellow. Whatever colour is chosen, don't change the colour from year to year.
The tags can be numbered on one end using a self advancing stamper. It is better to staple the tags loosely than tightly because the tagging may be done prior to harvest before the plant has stopped growing.
Don't staple the tags around the tassel because the tassel may break off.
The cobs from each inbred row will be harvested with the desired pollination dates from the pollination bags and placed at the front of their row. The cobs at the front of each row are collected and put into red mesh bags with the row number tag which is torn from the stalk of the first plant in that row. If necessary, if a cob and its pollination date information is to be kept separate, it is put into a second red mesh bag that is then put into the first red mesh bag that contains the row number and all of the other cobs from that row. Usually all the cobs are put in one red mesh bag with only one pollination date kept that is usually the average or the earliest date.
The bags from each range are then collected going across the range preferably in order and tied in bundles of ten or more. Twist the bags and their opening strings into a tight cord before tying them to prevent problems with knots and fraying.
The bundles are then brought to one side of the range where they are collected by someone going up the side.
In addition to the row number tags and cobs from each row, information regarding the dates of pollination may be wanted for individual cobs or an average date for the row. This will be on each pollination bag on the upper left corner.


Harvesters will find that tearing open the tassel bag from the back above the stapled corners and then removing the ear is easier than tearing the bag and ear off the stalk together and pulling the ear from the bag. This method also allows the ear to be left on the stalk for comparison with other ears in the row and leaves the bag on the stalk so it is not littering the Nursery.
Collected ears should be placed at the front of the row for collection preferably on top of a pollination bag representing an average pollination date so that the cobs are more easily seen. If information is wanted on pollination dates,the corners can be torn off the pollination bags or the cobs can be placed on top of their original pollination bags at the front of the row.
NOTE: Some workers just roll up the bag around the cob. Generic Seeds does not do this. The bags could potentially carry molds/fungi/pathogens or catch fire in the drying cupboard or require a higher heat to dry the cob.


Basically, all the cobs from a row are put into a red mesh bag together with the row tag from the first stalk of that row and a sample pollination date from the row that is an average pollination date or between the earliest and the latest dates. Sometimes, it may be desired to keep some cobs separate by putting them in individual red mesh bags and then putting these bags into the red mesh bag that contains all the other cobs and the row number tag.


The bags from a range are collected in groups of ten and tied together. The best way to avoid tangling and other problems is to hold all of the bags with one hand so the draw strings are all taut and then spin the bags together until the strings form a tight rope. Grab the lowest part of the rope and wrap the rope around at least two fingers, then draw a loop through the circle and tighten the knot,leaving one end to be pulled to loosen the knot.
Carry all the bags from each range to one side of the field and then collect all the bags from all the ranges in the back of a pickup truck.

Finishing the field harvest

After all of the selfs and misc. crosses in the Inbred Nursery have been harvested and stored, ready to be dried, the field is left alone while the other Nurseries are harvested. This gives some of the late varieties a good chance to dry down to near 24% moisture or so. This is just a ballpark figure.

Pollination work trash (bags)

Usually, all of the tassel bags and earbags are removed from the ground and the stalks and brought to places in the Nursery or to the side where they are burnt. Usually the bags have been burnt in the front headland rows. Consideration must be given to where the burning is done, as it can enhance fertility at that spot the next year. The bags are biodegradeable so they could be tilled into the soil with the stalks and leaves but what usually has happenned is that they were blown all over the place and made the farm look littered.

Combine work

After all the earbags and tasselbags have been disposed of, a combine is brought in and the entire Inbred Nursery is harvested with the combine and the seed is sold to a local feedlot for cattle feed.
(Note: If modern genetic engineering was involved, the practice of selling the seed for feed would probably not be allowed or there would be restrictions of some type regarding the disposal of plants and seeds etc.)

{C}Trash (Organic)

Next, a field mower (or a chain flail) is run across the field to chop up the stalks and leaves. This helps with the field work as well as helps to compost the organic material so it can make new soil. Try to spread the trash evenly.

Fall Field Work

Usually, a disk harrow has been used after harvest to chop up the stalks and prepare the field for spring. This is usually adequate for the Inbreeding Nursery because the plant population is thin and the plants are small.
With yields of 150 bushels per acre or more in the Maize Yield Trial areas, one is almost forced to use a moldboard plow to bury the organic material and get it decomposing to make more soil.

Shelling the Inbreeding Nursery

The inbreds are taken from the dryer or storage area and brought to the shelling area. It's best to sort the bags by 100's then tens, lining them up in sequential order and starting the shelling with row#1 and proceeding in sequential order. This is not always feasible but it can prevent some problems with misalignment of data when entering one row of data on a page.

For each row harvested, all of the selfed cobs from the row are placed in a square metal pan of about 23 cm x 23 cm x 5 cm that has sharp 90 degree corners. Be watchful for the odd misc cross in with the selfed material. Do the crosses later. It is basically a square cake pan. For each cob, an envelope is created with the row # printed at the top left corner, the year at the top right and in the center a dash and the number of the cob. The cobs are sorted from best to worse, shelled in order and the seed from each cob placed in its appropriate envelope. It is important that the row # on the envelope for all the cobs from the same row is the same. There is a temptation to start counting and write down the next row number when making more than one envelope for a row.

The shelling is usually done by hand. The butt kernels at the bottom of the cob are usually shelled first and then a row of kernels is shelled upwards to about halfway up the cob and then the cob is tightly gripped and twisted to shell kernels around the cob. {C}If the kernels are tight, shelling upwards using the tip of the thumb pushing downwards is easiest. {C}The kernels are shelled into a wooden framed tray with a metal screen bottom. The chaff and silks will fall through the screen leaving the kernels which are poured into the proper envelope.

Notes regarding how easily the cobs shelled might be wanted for some inbreds.

There is a cob sheller in the room but it is usually used only for large samples such as from the Isolated Populations.

The sheller is made of metal and looks like a meat grinder. The basic shape is like a funnel with a handle attached on the side to a circular plate with knobby teeth. The unshelled cob is put in at the top and the handle is turned forcing the cob to press against the knobby teeth which remove the kernels and the shelled cob falls out the bottom where it is caught with the seed on the metal screened tray. The cob is removed and thrown in a garbage barrel. The tray is shaken back and forth a bit to remove debris, and the seed is placed in a storage envelope.

Sometimes it is hard to open the harvest bags because the draw strings have frayed, the knot is too tight, etc. An old metallic staple remover that is like a flat finger has worked well to get in under the strings and pry out the knot.

Sample processing of maize genetic resources

Inbreeding Nursery


Data Processing

{C}At the present time, the data processing to create the labels for all of the new seed harvested is being done after the seed is shelled and placed in packages labeled with markers. One day this could be done all at once at the time of shelling.

The sheller gives the data processing department the Inbreeding Nursery Notebook that she has added comments to and filled out the #COBS column stating the number of cobs shelled for each row.

While it would be nice to have all the comments on the plants and the seed put into the computer, the top priority must be to get the #COBS column data into the computer and get the labels printed and placed on the seed packets.

The first step is to make sure the printed notebook version matches the computer version. The printed notebook version is given greater authority than the computer version. Any corrections in pen to the printed notebook should be added to the computer version. Check some random rows throughout the computer version to make sure that at least the row#, pedigree and source row data match the printed notebook.

To prepare for entering the data from the #COBS column, write a 0 in any blank cells in the #COBS column. This will help in keeping the data aligned so that the correct #COBS column value is in the correct row. {C}Enter the #COBS column data starting with the first row of the Inbreeding Nursery and move down the column to the last row of the Inbreeding Nursery.

Once all the #COBS column data is added to the computer version of the notebook, a preliminary Inventory to be called the #COBS Inventory can be printed out to be used by the breeder until the labels and pedigrees for all inbred seed is created in the next step. The #COBS Inventory simply is an Inventory of the number of cobs collected from each row. Note that until all seed labels are placed later, the #COBS Inventory is only tentatively correct. The #COBS Inventory can be used by the breeder to see what inbreds were not collected and how much seed is available for immediate shipping to others. It can also be used to make fast labels for seed being shipped immediately.


Creating Pedigrees

The seed that is shelled from each cob harvested from the Inbreeding Nursery must be placed in an envelope and labeled with a unique pedigree that is printed on a label and put on the envelope.

The pedigree for each row in the Seedlist/Notebook is for the seed that was planted in the row in the spring. New pedigrees must be created for the seed shelled from each cob collected from each row in the fall. These new pedigrees are printed on self-adhesive labels and put on the proper envelope containing the seed. The method of creating the pedigrees for labelling each envelope of seed is referred to in these notes as the "dash n method" because a dash and the number of the harvested cob is added to the end of the pedigree that appears in the Seedlist/Notebook. This system is basically a variation of the Jacoby system in genealogy. Each envelope of newly harvested seed will have a row#, year and -n cob number written in marker on it. This helps with placing the labels on the correct envelope and can be used until the full pedigree labels are printed and placed on the envelopes.

While the data for the inbreds is best kept in database format, most databases do not have the features needed to create/update the pedigrees using the "dash n method".Access may have that ability.

The "dash n" method being used to create/update the pedigrees involves the use of macros created in an EXCEL spreadsheet on a copy of a list version of the database. Each record is shown in a separate row with the field names heading each column. Once the pedigrees are updated, the new list of harvested seed pedigrees can be added to the Seed Room Inventory Database with a simple conversion from spreadsheet list to database records.

The term "Seed Room Inventory Database" is being used here to refer either to a single database of all the seed being kept in the seed storage room, or to all of the Inventory lists for each Nursery for each year. Prior to 2000, the seed stored in the Seed Room was accounted for by Inventory lists for each Nursery. These lists were created as spreadsheet lists and converted to database form for making the labels.

DASH n method

The "dash n" name comes from the procedure of adding a dash and the number of the cob harvested from a row to the pedigree of the seed that was planted in the row. For each row with n cobs harvested, there will be -n pedigrees to be created for the new seed from the n cobs.
Row Pedigree of planted seed Number of Cobs Harvested
1 COBB-8-3-1-1 3
2 COBB-8-3-1-2 2
Row Cob # Pedigree to put on seed envelope Source(row#)
1 COB#1 COBB-8-3-1-1-1 (added -1 to end) 1
1 COB#2 COBB-8-3-1-1-2 (added -2 to end) 1
1 COB#3 COBB-8-3-1-1-3 (added -3 to end) 1
2 COB#1 COBB-8-3-1-2-1 (added -1 to end) 2
2 COB#2 COBB-8-3-1-2-2 (added -2 to end) 2

Note that the row # from which the cob was harvested is now referred to as the SOURCE row of the seed.

The "Dash n" method may not be the best way to store data on the generations of selfing of plants but it works.

The "dash n method" does cause a lot of problems from the computer data storage point of view but it is preferred by the breeder over the version without use of the dash. The dash makes it easier to read the pedigree and determine the number of numbers (generations) in the pedigee.

E.g. COBB8311 is easier to read as COBB-8-3-1-1.

The mixing of text and numbers in the pedigree is the largest source of trouble for computer work. A sort will place numbers beginning with 1 such as 10,11,12, etc. before 2 which is then followed by 20 to 29 rather than 3 because the numbers are regarded by the computer as text when they are mixed with letters. {C}It might be preferable to not alter the copy of seedlist/notebook data at all but use it and the #COBS value to create a separate list as a new file in a completely different folder. This list would be used to print out the labels for the seed packets and added to the SEEDROOM INVENTORY DATABASE.

Work toward creating Excel macro

{C}General macro procedure

The ideal macro would locate the #COBS column, evaluate the numerical content of the cell in that column starting with the first row, and call the corresponding subroutine macro. The subroutine macro would locate the important columns in the same row such as ROW and PEDIGREE, copy the data of the columns in that row to a new location, alter the pedigrees appropriately for each cob shelled and move to the next #COBS column number in the row beneath.When a cell was reached with no value, such as at the end of the list, the macro would end or alert someone to a possible problem.
At the present time, pedigrees are printed in the notebooks in full to facilitate sorting and extraction procedures, however, the breeder prefers a skeleton system in which redundant pedigree data is NOT printed.
Skeleton Pedigrees (unfinished - In Col. 2 cells need to be padded with spaces not underscore and properly aligned.)
Row Skeleton Pedigree Full Pedigree
1 Cobb-8-3-1-1 Cobb-8-3-1-1
2 __________2 Cobb-8-3-1-2
3 _____9-1-1-1 Cobb-9-1-1-1
4 _______2-2-1 Cobb-9-2-2-1
5 __________3 Cobb-9-2-2-3
6 Holden-1-1-1-1 Holden-1-1-1-1
In the SKELETON SYSTEM the first instance of the pedigree is printed in full. Subsequent pedigrees with redundant data show only data from the first point of changes to the pedigree.

An Excel Macro (Not yet available: the 'Label records' macro below contains some of the desired elements but is incomplete and inefficient)

The macro below creates the new records to the right of 4 columns/fields holding the relevant information which is pulled from the Notebook spreadsheet or a database file.

Label records Macro

Option Explicit
Sub LabelList()
Dim MyRange As Range
Dim QTY As Integer
Dim rnganchor As Integer
Dim row As Integer
Dim Cell As Range
Set MyRange = Application.InputBox _
(Prompt:="Select the INPUT range", Title:="SELECT INPUT RANGE", Type:=8)
rnganchor = 2
'MsgBox ("Range Anchor is: " & rnganchor)
For Each Cell In MyRange
QTY = ActiveCell.Value
For row = rnganchor To rnganchor + QTY - 1
ActiveCell.Offset(0, -4).Range("A1:B1").Copy Destination:=Range(Cells(rnganchor, 8), Cells(rnganchor + QTY - 1, 9))
Application.CutCopyMode = False
ActiveCell.Offset(0, -1).Range("A1").Copy Destination:=Range(Cells(rnganchor, 11), Cells(rnganchor + QTY - 1, 11))
Application.CutCopyMode = False
Cells(row, 10).Value = Cells(ActiveCell.row, ActiveCell.Column - 2).Value & "-" & row - (rnganchor - 1)
Next row
rnganchor = rnganchor + QTY
ActiveCell.Offset(1, 0).Select
'MsgBox ("Range Anchor is: " & rnganchor)
Next Cell
End Sub
Private Sub CommandButton1_Click()
End Sub

Macro for erase button {C}Sub Button5_Click() {C}Range("H2:K25").Select {C}Range("H2:K25").Clear {C}Range("A7").Select {C}End Sub

Using Microsoft Excel functions

The pedigree string can be parsed using the dashes as delimiters so that the pedigree string is split into separate columns for each part that is separated by a dash. The first column will contain the letters and numbers to the left of the first dash. The subsequent columns will contain the numbers after each dash and be converted to numerical values rather than text.

This is done using the TexttoColumn, Find, Left, Right and Mid functions in formulas.

See Mr. Excel episodes 157 to 162.

Episode 157: Breaking Apart a Column [4]

Episode 158: MID() function

Episode 159: Get characters up to a dash

Episode 160: Get characters after the dash

Episode 161: Get characters after the second dash

Episode 162: TextToColumn function

A Manual Method of Creating the New Inbred Pedigrees {C}1. Place the cursor on the first number in the first row of the #COBS column. For each #COB column number value a macro will be created and assigned a shortcut key. Whenever a particular number appears in the #COBS column, the corresponding macro is executed by pressing the appropriate shortcut key. Each macro inserts the necessary number of new rows into the spreadsheet list and places the proper pedigree for each cob on the proper new row.

For each cob from a row, the macro will insert a row or rows and alter the pedigree for that particular row accordingly. {C}For #COBS = 0, the macro only has to move the cursor down to the next row and be ready to read the next #COBS value. This is because no cobs were harvested and there is no seed and therefore no label is needed for an envelope of seed. The cursor can be moved down one row manually by pressing the cursor down key or by creating a macro to do so and assigning the macro to a shortcut key.

For #COBS = 1, the macro must locate the Pedigree field in the same row as the #COBS value and add a dash and a 1 to the end of the pedigree. Then the cursor must return to the #COBS column, move down one row and be ready to read the next #COBS value. A macro can be created and assigned to the "A" key. Each time the number one appears in the #COBS column press the keys that activate the "A" key macro such as 'CTRL-A'. The key can be labeled with the number 1 using masking tape so what the key is for is not forgotten.

For #COBS = 2, the macro inserts 1 row beneath the row containing the #COB value. Then the macro copies the row#, family, pedigree,Source row etc. info from the row above the blank row and places that data in the new row. The macro moves back up to the row above and adds -1 to the pedigree. The macro next alters the pedigree in the row below by adding -2 to the pedigree. The cursor then moves over to the right and down one row to the next #COBS value in the list. A macro named "TWO" can be recorded and assigned to the 'S' key. {C}The macro for #COBS = 3 and other higher numbers is very similar. Insert n-1 rows (E.g. For n=3, 3-1=2 rows to insert), copy the info from the same row as the #COB number to the blank inserted rows, alter the pedigree of each row until "-n". Move back to #COBS column and move down one row.

Use of this set of macros then, involves going down the #COBS column pressing the appropriate shortcut key for each #COBS column value. It is easy if the shortcut keys are beside each other. E.g. A=1,S=2,D=3.F=4,G=5,H=6,J=7,K=8 etc. {C}Until the method is fully automated and can recognize #COBS column number values itself, one can put the value on a piece of masking tape and put it on the appropriate key making memorization unnecessary.

Make macros for 1 to 12 at least. Macros for #COBS > 12 can be created on the spot by executing the highest value macro and then adding manually as many more rows as needed.


A possible shortcut is to first do the macro for #COBS=1 all at once on all rows rather than for each row as the number 1 occurs. This makes assigning a shortcut key such as "A" to a macro for #COBS=1 unecessary. Instead, the "A" key can be assigned to a macro that moves the cursor down one row as for #COBS=0. When the #COBS column value = 0 or 1 , press the "A" key.

After all pedigrees are altered by adding "-1", one begins in the #COBS column from the first row, executing the proper macro for each #COB value as it appears highlighted by the cursor as it moves down the list. {C}Addition of "-1" already to the pedigrees means that for rows with #COBS = 1, the pedigree for the harvested seed is now correct and the macro to be used when #COBS=1 just moves the cursor down to the next row.

First cob shortcut macro

Create a macro that adds "-1" (a dash and the number 1 with no parentheses) to the end of all pedigrees in the seedlist/notebook file. The macro should be cyclical and not stop until all the pedigrees have had "-1" added to them. "-1" must be recognized as dash 1 and not minus one. The macro will add "-1" to the end of each pedigree and then move down one cell to the next pedigree. Various ways can be used to make the macro cyclical (repetitious). Holding the key assigned to the macro down is a simple way used in Excel. In VP-Planner a circular reference to a cell containing the macro label results in a macro that does not stop until CTRL-Break is pressed. The macro in VP-Planner used the F2 key to enter the cell, then -1 was added and the cursor moved down one cell. In Excel one can use the Concatenate function but may need more columns to hold preliminary results. Excel also uses the F2 key to enter cells but there was a problem figuring out how to do so in a macro. It may be possible to use the F2 key in a macro the same way as used in VP-Planner.

If the First cob shortcut is used, no macro needs to be created for #COB column number values of 0 and 1 except a null macro that merely moves the cursor down one row. A value of 0 means no cobs were harvested so AFTER pedigrees are created for seed labels, the rows with #COB numbers of 0 can be sorted out as a group and deleted.

It might be wise however to keep the Inventory list of COBS harvested including rows for which no cobs were harvested. It can be handy to know which rows were not harvested. The COB INVENTORY can also be used by the breeder for labelling and shipping seed until all of the labels are printed and placed on the appropriate envelopes.

If using Excel it is recommended not to sort until after pedigrees are created to avoid any possible problems with data misalignment as a result of an incorrectly assigned sort. Excel uses a handy but DANGEROUS assumption that if an entire area is not selected, then it is to sort data from its present position to blank rows above and below and blank columns on each side. Unless properly selected, Excel will not sort data in one column together with other data in the same row if there is an empty column between. It may be possible to select from the Seedlist/Notebook database only records with #COBS value >0 and avoid having to sort #COBS = 0 records out of the list.

It is very important to check all the macros on a test sheet first before executing them on the copy of the Seedlist/Notebook. Errors are not flagged so a row that is deleted or altered by mistake will go unnoticed. {C}Be careful not to execute the First Cob Shortcut macro more than once on a cell or list.

Inbred Pedigrees

Creating pedigrees for BLENDS

A blend is a word to designate that the seed of different cobs in a row from the Inbreeding Nursery have been mixed together. It is contained in brackets after the dash. Blends are frowned on by breeders.

- (1-4) means seed of cobs 1,2,3 and 4 have been mixed together. {C}- (1,3) means seed of cobs 1 and 3 were mixed.

If the mix has more than 4 cobs it might as well be called a bulk and labeled -blk or -bk .

Placing labels on seed envelopes

Most of this data pertains to the Inbreeding Nursery. {C}The format for labels on #6 envelopes is: {C}Year of harvest on upper right corner, row# on upper left corner and pedigree centered and a few lines from the top. Be sure to be consistent from year to year regarding the side the year of harvest is put on. You don't want to mistake a year for a row#. Since people read left to right, I prefer the row # to be on the left.

531 1995

For the Inbreeding Nursery, if #2 coin envelopes are used, the label is put on sideways with the row number on the upper left corner, the pedigree centered a few lines below, and the year on the lower left corner.


Matching labels to envelopes

The creation of the labels is quite simple if the row# and pedigree information is in a database. The format of the label is specified with fields and the program prints one label for each record in the database list. The real problem is matching the labels to the seed envelopes. Information in the Notebook may have been entered incorrectly or on the wrong line resulting in either too many envelopes for a variety or not enough. Double check that the computer data matches the Notebook and if necessary, compare questionable seed with the seed of nearby rows. If there is any doubt about the identity of seed it must be thrown out. The row # on the label and the last -n number of the pedigree should match the row # and -n number on the envelope.

If you find the Notebook and premarked envelope data is frequently incorrect, set up procedures at shelling time to prevent whatever the problem is.

Incorrectly marked envelopes

Sometimes when a person is marking the envelopes with a marker, they either start adding one to a row # or make two cob#'s the same.

E.g. 156, -1, 156, -2,157,-3,157,-4 or 156,-1,156,-2,156-2,156,-3. {C}One must be aware of this problem and be on the lookout for it. The best way to eliminate it might be to automate the process somehow.

Data entered incorrectly to the Notebook

E.g. If the problem is that data is being entered on the wrong line in the Notebook because rows are being shelled in no particular order and the blank space and small width of lines make following a line across a page from row # to the column for # of cobs difficult, (i.e. Row #5 is being done followed by row #32 and the person is not recording on the correct line for various reasons), consider putting in place a policy such as presorting the inbreds and shelling them in sequential order from row #1 to the end. This won't stop the entering of data on the wrong line after a gap of rows for which nothing was collected, but would be a start.

Data entered incorrectly to the computer

If the system is not automated, and the notebook data is entered manually into the computer, set up procedures to ensure that the Notebook data and the computer data match. A procedure that I used was to make sure that a value was entered in the notebook for every row. If no cobs were collected and the space in the #Cobs column was left blank, I filled it in with a zero. I did this for the entire nursery before entering the data to the computer.

Each row # then had a value and the data was entered by going straight down the #COBS column from top to bottom entering all numbers including zeros.This procedure prevented misalignment of the data caused by skipping rows and restarting when entering data to the computer, at the expense of entering zeros when no cobs were collected. One might also consider using scanning and character recognition.

Multiple rows with same pedigree

Another problem is multiple rows of the same pedigree. The envelopes may be marked with different row and cob #'s. Use only one row number and then sort the envelopes from best seed to worst and relabel them with consecutive cob #'s.

E.g. Row # 5 and row #6 have exactly the same pedigree. Four cobs from Row # 5 and three cobs from row #6 were harvested. At shelling time, the cobs in each row were rated and the best cob given a cob # of -1. There are 7 cobs from the two rows to be resorted from -1 to -7. Row #5 will be used to designate all the cobs. The seed from the cobs from Row #6 will be compared to those from row #5 and sorted from best to worst among the seven cobs.

Be sure to update both the Notebook and computer files regarding this merge of rows 5 and 6.

Sib Nursery

Sib Nursery Notebook covers

Notebook sample page

: picture to be added of Sib Nursery Notebook spreadsheet page

Sib Nursery Pollinations

Flagging the blocks of material

With the SIB Nursery Notebook at hand, the first row of each block of material is marked with a flag made using a tassel bag,china marker and staples. This should be done starting from Row 1 and moving through the Nusery in sequential row #, range by range.

Always make sure that the rows specifying the block of material in the field matches the notebook. If a row doesn't look like it belongs in a block it should be cut down and not used. Make sure to record in the SIB Nursery Notebook any discrepancies between the field and notebook so that the two are the same.

Sometimes, when the seed is made up, a person might fill the wrong envelope with seed near the row# of the split between blocks of material so that the second row or second last row in a block might contain the wrong material. If this happens, chop out the row with the wrong material.

The flag is just a tassel bag turned sideways with a simple arrow pointing up drawn with a China Marker near the closed end of the bag and on only one side. The arrow should be drawn on the front side and not on the side with the seam.

The arrow means that all rows from the flagged row up to the next flagged row (but not including the next flagged row) are the same material.

NOTE: It is VITALLY IMPORTANT that the arrow be on only one side of the tassel bag and that the direction of increasing row number is past the flag and not before it. When traveling through a range in the direction of increasing row number as in the planting plan., all the arrows should be visible. If only the backs of flags can be seen and no arrows, the person is going the wrong way.

E.g. Rows 1-5 are B7312 material, Rows 6-10 are R8W material and Rows 11-20 are Tux material. Rows 1,6,and 11 are flagged.

Earshoot bagging

  • Pollination Apron/Pouch
  • Number 208 or longer Lawson Shoot bags.
  • Possibly safety glasses for working around tall plants

Shootbagging/Earbagging is done much the same as for the other Nurseries although there may be more problems related to maturity differences of blocks of material.

The shoot baggers can move through the ranges of material perpendicular to the direction of the rows of plants. Be careful not to break plants while walking through. Eye protection is a good idea too. A pair of safety glasses would be good. In the Sibbing Nursery some of the material from the highlands of Mexico or from equatorial regions are very tall and the leaves are as sharp as paper against the eyeball.

The biggest problem is getting an shoot bag on the top earshoot. Often the second earshoot may appear before the first so one must carefully check to see if there is an earshoot forming above the visible one. It's better to bag a large earshoot near the top than the first small earshoot one sees. This requires some judgement so that the earshoot doesn't get missed before silking. Shoot bagging the second highest earshoot is preferable to having no earshoots bagged at all. {C}Some of the varieties have earshoots appearing over one's head so this can be difficult.

Also there may be problems with earshoots that appear fully silked before an earbag can be applied.

If there are only a few people available to do the shoot bagging and pollination of the nurseries, it's best to do the shoot bagging whenever pollination can't be done. Early morning is not recommended because you will be drenched by dew. Evening is best but it can also be done after pollinating in the late afternoon.If there are enough people, the shoot bagging can be done all day.

The SIB Nursery can be shoot bagged from the front of the Nursery to the back or from the back of the Nursery to the front and even from the middle either way. One doesn't need to worry much about the blocks for shoot bagging except when a block has enough shoot bags and can be skipped or has none and needs shoot bags.

Some blocks of material will be ready before others so one can skip some blocks going through each day but remember to keep checking them.

If the entire Nursery can't be completed in the time allowed, vary the starting point from one end of the field to the other and also from the middle either way. Keep track of early blocks so they don't get missed in the middle.

As the block starts to get more than a dozen shoot bags, start to get tougher regarding the plants to place shoot bags on.



  • SIB Nursery Notebook
  • Pollination Aprons/Pouches
  • small knife
  • Number 402 Lawson(TM) Tassel bags or longer
  • 1/4 in. staples
  • staplers
  • China Markers
  • hat
  • possibly safety glasses.
A person can get covered in a good layer of pollen in this Nursery so a hat and a long sleeved shirt is not a bad idea.

NOTE: This is NOT the Inbreeding Nursery so it isn't necessary to mark the tassel bags.

The material is not selfed but is crossed together as a block. The silks should be quite long when pollinated and they are not cut back. However, the silks must not be exposed or hang out of the tassel bag after being pollinated.

Before pollinating a block, make sure you know the exact limits of the block's first and last rows. When working backwards from the far end of the field to the front it is best to first, exactly identify the first and last rows of the block and then start from the flag moving in the direction of increasing row number for that block.

Pollinating within a block of material {C}Take pollen from a lot of good plants on one end and start pollinating at the other end. This helps to limit selfing. Collect the pollen as for the Inbreeding Nursery making a kind of pollen applicator and pollinate as many good plants as possible.As one goes along, more pollen can be taken from good plants and applied to the other side of the block or to plants that make a good match. Don't take pollen from a good plant before pollinating it but after.

Use one hand to hold the pollen applicator and the other to pull a tassel bag from the pouch and slide it down over the earshoot as soon as the pollen has been applied.

Staple the tassel bag to the stalk or on the sides of large ears.

The Sib Nursery has more plants and is more protected from wind than the Inbreeding Nursery so if necessary, the stapling can be left for another person or the bags can be left unstapled for a while. This makes things easier for applying pollen.

Sib Nursery Harvest

The Sib Nursey is harvested one block of material at a time.

All pollinated cobs in the block with tassel bags covering them are collected and placed in the middle of the pathway at the front of the block and halfway between the first and last rows. The cobs are collected in a large orange mesh bag and a tag with the row# of the first row is placed in the bag.

The bags are left in the pathway to be picked up later by carrying all the bags for each range to one side where they are put into a pickup truck. Be very careful not to overlook a bag especially if there is a small block with few ears collected.

Creating Pedigrees for newly harvested Sib Nursery seed

The seed from the Nursery will have been dried, shelled and put into large envelopes. Where more than one envelope is used, the seed will have been mixed well before being poured into the two envelopes. Each envelope has the first row# of the group and the year put on with a black permanent ink marker.

The Sib Nursery is assigned rows 7000 - 8999. These rows are reserved for Sib Nursery material every year to make association of those numbers with Sib Nursery material common. Material sibbed in the Inbreeding Nursery should not be with Sib Nursery material. Also a colour should be assigned to the Sib Nursery's harvest tags and not changed from year to year.

Check the notebook for any changes to the Sib Nursery row numbering, pedigrees etc. The notebook version is authoritative.

Ensure that the printed notebook and computer notebook version match.

The usual format for printing the Sib Nursery Notebook has been to put the information regarding a group (such as pedigree and source row) on the first row number of the group and leave the other rows of the group empty. It would be nice if the creation of the formatted notebook version of the seedlist was automated so that the number of blank rows to be added for each group was done by a subroutine.

The goal is to get the Notebook format reduced to a list of the groups with no spaces between groups and then to alter the pedigrees for the labels to be placed on the envelopes. Only the first row number of each group is needed to designate the group. Check for any row numbers between groups. There should be only one mix of seed per group. A sort by pedigree followed by row number will obtain the list (also try by row number and pedigree).

Be careful to select all applicable columns for the sort if using an Excel spreadsheet.

Sib Nursery Pedigree

Please note that the pedigree notation described below is completely idiosyncratic and I don't know what system private companies, government researchers, or researchers at CYMMYT use.

The format for Sib Nursery pedigrees is -nSIBx. This format is completely unlike the Inbreeding Nursery. Normally, for the bulk seed from each group, the format is -SIBx. The n is for assigning numbers to cobs being taken out of the SIB Nursery and to be planted into either Crossing blocks or the Inbreeding Nursery the next year.

The x in the format is for the number of years the plants have been in the SIB Nursery. For the first year it is just -SIB or -SIB1. For the second year it is -SIB2. For the third year it is -SIB3 and so on for each year. The only thing that changes in the pedigree from year to year is the final digit. Note that capitals are used for SIB in the SIB Nursery but in the Inbreeding Nursery only use lower case -sib.

Sib Nursery Pedigree by Year
Pedigree Description
1995 POP Leaming Seed Harvested from the Leaming Population grown in Isolation
1996 Leaming-SIB1 The seed was grown in a group of twenty rows in the SIB Nursery
1997 Leaming-SIB2 The seed has been grown for 2 years total in the SIB Nursery
1998 Leaming-SIB3 One more year in the SIB Nursery
1999 Leaming-SIB4 The fourth year in the SIB Nursery
2000 Leaming-SIB5 Fifth year. The group bulk. Should contain seed from all harvested cobs of the group including seed from each of the cobs extracted below.
Leaming-1SIB5 Fifth year. Cob#1 Seed from only this cob.
Leaming-2SIB5 Fifth year. Cob#2
Leaming-3SIB5 Fifth year. Cob#3
Leaming-4SIB5 Fifth year. Cob#4
Leaming-5SIB5 Fifth year. Cob#5

The seed from the extracted cobs will be planted in a different nursery the next year.

Maize Researchers at Iowa State University use a notation involving C(n) to denote the number of Cycles (C) or times that material has been grown.

Method of Creating Pedigrees for SIB Nursery Seed

I used a manual method to create the new pedigrees since the list is small and the way of showing the updates does not seem well suited to automation. I first checked that the notebook and computer versions matched, then sorted to get a list of the SIB Nursery groups without blank rows.

I then altered each pedigree manually by entering the cell, deleting the last number and replacing it with a number 1 greater. The table below is what would appear based on the Sib Nursery Notebook for that year.

Sib Nursery Groups
7850 LAN LANKING-SIB3 7700
7860 SS BSSR3-1-2-3-SIB5 7720

To update this information for the harvest inventory, enter pedigree cell of row# 7850, erase 3 at end of pedigree. Replace 3 with 4 because the material has been sibbed one more year. Exit cell. Do next cell below. Change 5 to 6. Note that the pedigree of the group starting at row# 7860 is for a plant that was selfed 3 times in Inbreeding Nursey then SIBBED in the SIB Nursery for 5 years.

For single cobs extracted from the SIB Nursery I also used a manual method. It was easy to just copy the new group pedigree and then add in the cob #'s.


1999 Notebook LANKING-SIB3
1999 harvested group seed bulk LANKING-SIB4


There are many sources of germplasm to begin the work.

  • Maize Genebanks
  • Universities and research groups might sell or license small amounts of inbred seed.
  • Seed company catalogues
  • Heirloom seed collectors that publish catalogues.
  • Buy a bag of commercially available hybrid maize seed
This shortcut method was used by plant breeders in the past.This was perfectly legal (obtaining the exact inbreds used to create the hybrid is close to impossible) and was a way to build on the shoulders of giants. But the owner of the plant breeder's rights for the inbreds of the hybrid seed objected to competing against its own genetics so terminator genes were developed.This method also decreased genetic diversity.


Maize Yield Trials

This section has been moved to a subpage that can be reached from the link above or from a link at the top of this page beneath the link for this page.


  • Robert W. Jugenheimer, "Corn: Improvement, Seed Production, and Uses" Krieger Publishing Company; Reprint edition (February 1986)
    (ISBN 0898746620)

The 1950s FAO version is the first book I could find at a University regarding the work I did but the information I was seeking was never given in detailed form and was only mentioned in a Miscellaneous section as a trivial aside.I found the Reprint edition in a public library but the references to addressograph plates and punch cards are outdated. There are some good photos of some relevant things. This publication has lots of good information and might be a good place to start.

  • Illustrated Guide On How To Work With Corn (1988) Stanford University


   THIS is the kind of hat write up I have been seeking!Some elements of it are outdated but can be updated. There are some differences in procedures that should be noted well and handled. 
    It can be found at the Walbot Lab web site in the methods section.
  • Walbot Lab at Stanford (Research on Anther Development) [6]

link walbot Lab

   Note: Lots of great links in the Links section of the Walbot Lab website.
  • Managing Trials and Reporting Data for CIMMYT's International Maize Testing Program

[7] [8]

  • Manjit S. Kang, "Handbook of Formulas and Software for Plant Geneticists and Breeders", (2003), Food Products Press and The Haworth Press Inc.
    (ISBN 1-56022-948-9) (hard)
    (ISBN 1-56022-949-7) (soft)
    (Dewy Decimal #: QK981.5 .H36 2003)
Table of Contents, Preface and all of Chapter 1 available on internet
Cover page, Table of Contents and Preface (9 pages)

':(Dr. Kang's Handbook of Formulas is NOT what I'm seeking and is more for the Breeder. The reason given for its publication, however, is the same as my own))'

Note the statements regarding software in obsolete DOS form, scattered research software(something different used by different research groups all over the world,(usually a computer science graduate student program often on a different University mainframe in a multiplicity of programming languages and commercial software products)).


Maize Breeding and Seed Production Manual Food and Agriculture Organization of the United Nations Office of the Food and Agriculture Organization in DPR Korea [9]

Corn Breeding: Lessons From the Past - Overview and Objectives

Ken Russell

Associate Professor, Department of Agronomy and Horticulture at University of Nebraska Lincoln (UNL), USA
Leah Sandall

Graduate Student, Department of Agronomy and Horticulture at University of Nebraska Lincoln, USA

Genetic and Genomic Toolbox of Zea mays

Natalie J. Nannas and R. Kelly Dawe

GENETICS March 1, 2015 vol. 199 no. 3 655-669;

This link is dead. It is no longer accessible to the public and is now behind a password protected faculty login.

  • Conduct and Management of Field Trials
  • Greenhouse Care for Transgenic Maize Plants
  • GREEN BOOK: Walter R. Fehr and Henry H. Hadley, "Hybridization of Crop Plants". 1980, American Society of Agronomy Inc., and the Crop Science Society of America Inc.
    (ISBN 0-89118-034-6)
    (Library of Congress: SB 123.H9)
    Notes: Pollinations, Corn, pp. 299 – 312, Common Bean, pp. 273 – 284, Triticale, pp. 681 – 694, Barley, pp. 189–202
  • Neal C. Stoskopf (University of Guelph), "Plant Breeding", Westview Press, (ISBN 0-8133-1764-9)
(SB 123 S89 1993)
Notes: On the subject of Plant Breeding, there are quite a few textbooks available on University, College and Public Library shelves.I found this one at a small college.These texts are not what I'm seeking at the moment.
  • Colin J. Driscoll, "Plant Sciences: Production, Genetics and Breeding" Nov 1990, Ellis Horwood Ltd, (ISBN 0136770487)
(ASIN 0136770487)
Notes: Experimental Design, Analysis of Variance,Completely Randomized Design,Randomized Complete Block, Factorial Experiment, Chi squared table, t table, I like Mr. Driscoll's text the best but it's out of print.It also doesn't get into the mechanics of the work.
  • Arnel Hallauer, "Specialty Corns (2nd Ed.)", 2000, CRC, (ISBN 0849323770)
Notes: Ch. 14 Temperate Corn - Background, Behavior and Breeding by Forrest Troyer, Notes on breeding methods, pollination work, drying seed etc. ***), Breeding White Endosperm Corn (39 pages)
  • ICIS-CIMMYT modified Purdy notation in GMSInput.pdf,(Pg. 7 of 14)
  • Field Scouting Guide (149 pages)
(Dewey Decimal: 632.9 FIE)
Note: The information is specific to the Province of Manitoba, Canada
Available from:
Food Development Centre
Box 1240
810 Phillips Street
Portage la Prairie, Manitoba R1N 3J9
Phone: 204-239-3150
Fax: 204-239-3180
  • Erwin L.; Leonard, Warren H.; Clark, Andrew G. LeClerg, "Field Plot Technique", 1962, Burgess Publishing Company
Notes: I like FIELD PLOT TECHNIQUE the most so far.
  • Gomez and Gomez, "Statistical Procedures for Agricultural research 2nd Ed.", 1984, John Wiley & Sons
(ISBN 0-471-87092-7)
  • Field Corn Seed Crop Inspection Procedures
In Canada, when the Breeder's seed is released to be commercially grown by seed production companies and sold as certified seed, it must be inspected by licensed or official inspectors. The document mentioned below contains good information that one should be aware of as a maize field technician and it has some good illustrations as well.

  • CIMMYT photo collections on Flickr

[http:// Photos of Maize Land Races]

[http:// Maize and its Relatives]

Journal Articles

  • "A Proposed Standard Method for Illustrating Pedigrees of Small Grain Varieties", Purdy,L.H.,Loegering,W.Q.,Konzak,C.F.,Peterson,C.J.,Allan,R.E.,
CROP SCIENCE, Vol. 8: July–August, 1968,(Pp. 405-406):ISI
  • "A Batch processing download tool for historical crosses and pedigree selection data", William H. Eusebio

  • ICIS-CIMMYT modified Purdy notation. See page 7 of 14 for an example of a CIMMYT maize pedigree.
  • Prelude to Foundation [15]
  • FAO Grassland Species Profile of Maize [16]
  • some information on writing pedigrees is in a document regarding CIMMYT's Excel add-on Fieldbook software.