Jennifer Ewoldt, Rural Route 4 columnist
I had a question emailed to the Quad-City Times about seed corn production, and how it has changed over the years. We do not grow any seed corn ourselves, but I will do my best to try to explain the process and some things that have changed.
Farmers who grow seed corn do it on contract for seed companies. The companies will pay them on contract a certain amount for growing the seed, usually per acre, and then the company provides the seed to plant. In the fall, the seed corn is harvested by the company, and the new seed corn seeds are processed and prepared for sale the next year. That’s the short version.
The basic process of growing seed corn has not changed for decades. Two varieties of corn which are to be crossed are planted in the same field, and then the resulting seed is harvested. This hybrid seed is hoped to be better than either of its parents in some way or another. This is similar to what happens in crossbreeding all sorts of plants and animals to achieve something which is better than the parents. In genetics, this is called hybrid vigor. Sometimes the offspring is not better than the parents, and this crossbreed is left by the wayside and not produced any more.
In seed corn production, the majority of the rows are the “female” variety. It’s not that this variety is actually female – it’s that this variety will be allowed to produce ears which will be harvested. Usually there are about 4 to 5 rows of the “female” variety to every row of the “male” variety. The “male” variety is allowed to grow and produce a tassel, thereby providing the pollen for reproduction. The “female” variety is detasselled, or has its tassel removed. Therefore, it cannot pollinate itself. You will see this in the seed corn fields, where some of the rows look like they have had their tops chopped off (because they have), while there are a few rows that are still tall (those are the “male” variety).
After pollination, the “male” variety is chopped off at the ground, or rolled flat on the ground, because it will never be harvested. It likely pollinated itself, so its ears are not a hybrid. The “female” variety plants are allowed to finish growing to maturity and produce ears of corn full of the new hybrid that was created. In order to avoid cross-pollination by another variety in the next field, there are restrictions on how close a seed corn field can be to other corn fields. Usually, they are surrounded by several rows of the “male” variety, and then they must be surrounded by soybean fields for a certain distance. This prevents airborne pollen from other fields sneaking into the mix.
One of the biggest changes in the process is in detasselling. Many years ago, a person (often a teenager) could contract to keep a certain number of acres or a certain field detasselled. He or she would walk through the field, pulling tassels off the female plants. Over time, machines were developed to do this, and it became more of a business. The person who owned the machine would hire several people (usually teenagers) to work on the machines, feeding tassels into the cutter, and they contracted to take care of a large number of acres. Now, machines make the first pass through the fields with just a driver, cutting the plants a few leaves above the ears. This is followed by a detasselling crew on foot a week or two later to pull any remaining tassels that didn’t get cut on the first pass. While it’s still often a good summer job for teenagers, the detasselling crews are now often adults and sometimes foreign workers. They cover hundreds of acres over the season, and may be directly employed by the seed companies.
The second biggest change in the process is the global nature of corn production. In the past, a new hybrid had to wait until the next year to be planted so breeders could see if it turned out to be a good cross or not. Now, seed corn hybrids can be grown in Hawai’i and in South America (mainly Argentina and Brazil) during our winter, producing results from a couple of cropping seasons in different conditions before the next Midwest growing season begins. If it was successful, this variety can be brought to market in just one or two years, instead of 3 to 5 years. This is a huge advantage for seed corn development. It also allows for mass production of a good hybrid to obtain large quantities of seed for the next Midwest growing season. Likewise, our seed corn grown here may be for use in Brazil this winter.
Interestingly enough, seed corn is ALWAYS a hybrid – you never plant a field of one variety to get more of that variety. It wouldn’t be a hybrid any more if you did so, and probably wouldn’t grow as well. This is also one reason why farmers do not save corn seed to plant the next year. Another reason is seed patents which prohibit farmers from keeping back seed to plant the next year.
Now that you’re imagining male and female corn – please remember that all corn plants have both male and female parts, but the end result we want is always ears of corn full of good corn kernels. Plant breeders and seed corn companies are working to make those corn plants and kernels better and better all the time through hybridization and selective breeding.
Get opinion pieces, letters and editorials sent directly to your inbox weekly!
August 03, 2020 at 06:22AM
https://ift.tt/3gpqLtB
Rural Route 4: Taking a look at seed corn production - Quad City Times
https://ift.tt/3gguREe
Corn
No comments:
Post a Comment