38 Ate Today? Thank a Farmer. Better Farming | February 2024 ’WE’VE MADE GOOD STRIDES’ More thoughts on where we are with genetics & fertility By Patrick Lynch Last month I wrote about changes in weeds, herbicides and tillage. Now I will discuss changes in genetics and fertility. When you look at the yield increases in corn, soybeans and wheat, some of the reasons given are better planting, fertility and disease control. New genetics is another. Breeders have looked for a “high-yield gene” for years, but there is none. While the average yield of corn on many farms is over 200 bushels per acre, and the highest on-farm corn yield in 2023 was 623.84 bushels recorded in the State of Virginia by David Hula, researchers tell us that the genetic potential for corn is higher than that. The reason we do not get high yields is because of all the stresses that corn must endure, one of the biggest of which is competition from weeds. To that end, breeders introduced genetic tolerance to glyphosate. This increased the average yield since it was easy to get clean fields. It became obvious that the path to higher yields was to reduce stress. After so many years, we developed glyphosate-resistant weeds. Now we have corn hybrids that are resistant to 2,4-D. Corn hybrids are already resistant to dicamba. There is talk about yield drag with the introduction of these new genes. There may be a yield reduction in side-by-side research trials, but the reality on the farm is that if growers can keep fields clean, then on-farm yields go up. Another reality is that some herbicides do stress planted crops. If you looked at older hand-hoed research trials, the hand-hoed treatment generally outyielded the best herbicide treatment. If you grow soybeans, you’ve probably witnessed a yield loss due to herbicides. It’s common in corn as well. As we develop more genetics with better tolerance to herbicides, we reduce herbicide stress. Breeding is now attempting to make a corn hybrid that produces its own nitrogen the way legumes do. It may be a long time before we see this to a measurable degree so that farmers can reduce their nitrogen rates. We are more apt to see biological inoculants that help corn produce nitrogen. This research will be a collaboration between the biological sector and the plant breeding sector. We’ve seen some breakthroughs with the RNA interference (RNAi) breeding program. Specifically, we have hybrids with this technology that control corn rootworm. There is a concern that corn rootworm will overcome this resistance. This probably will happen, but on the other hand, as breeding programs progress, I’m sure we’ll have more RNAi genetics to control – not only corn rootworm, but also other corn insects such as western bean cutworm. These genetics will increase yield by decreasing stress. An area of great concern to me is hybrids that allow gibberella and other ear moulds to grow. Last year we saw big differences among hybrids, and we don’t know why – but breeders will figure it out. Certainly, tight husks and upright ears appear to increase DON levels, but there must be more reasons. Perhaps some hybrids just don’t allow the spores to travel down the ear silk. One thing that we did not have four to five years ago was variable planting. crops: the lynch fileS New planter technology allows for variable seed drop. Patrick Lynch photo
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