The Lynch File: There is no such thing as a gene for higher yield

Wednesday, January 16, 2008

Over the past 40 years, we have bred higher-yielding crops by improving plant health and not by inserting a 'yield gene'

by PAT LYNCH

There is a belief that, when breeding crops, you can insert a gene for higher yield. The reality is that "there is no gene for higher yield." Over the past 40 years, we have bred higher-yielding crops by improving plant health and not by inserting a "yield gene."

During this time, more money and effort has been put into breeding corn than soys. That is why corn yields continue to grow, while soys yields are levelling off. (The widespread use of bin run soybeans has resulted in less breeding in soys.)

The improved plant health in corn has come from better insect resistance, both corn borer and rootworm; better disease resistance, Fusarium, Gibberellins and Pythium (all common stalk diseases); and better root disease control.

But there are other ways that we are improving plant health. The first is the use of fungicides. This year more than seven million acres of corn were sprayed in the United States with the fungicide Headline. There was a lot of scoffing from university and government extension people about this. While the spraying was going on, the public websites were full of ridicule about how foolish these growers were.

I believe that, when that many growers over a wide area are following a certain practice, it must have some merit. The "doubting Thomases" are saying: "If I can't see it, I don't believe it." They believe that if there is no visible disease control, it is not happening. But I think that they are wrong. The results are coming back with a yield increase from spraying Headline of about 10-12 bushels per acre.

I look at many of the treatments we use for better health in both humans and livestock, whether they be vitamins, antibiotics or cancer treatments. The majority of these are effective because they are working internally. You cannot see a visible outward difference.

This may also be occurring with crops and some treatments. The fungicides we are using may be working internally to give protection against diseases. It is not unrealistic to believe that fungicides are working internally on diseases in the plant similarly to the way products work internally on humans and livestock.

Another area of plant health is nutrition. Many human doctors and veterinarians believe that you can offset various illnesses with better nutrition. Similarly with crops, I believe we can get better plant health with better plant nutrition.

I don't believe we will be using shotgun mixes of micro nutrients to get better plant health, but there is a reason to believe that balancing plant nutrients will work. We know that, if you apply too much potash, you can limit magnesium availability. If you put on too much lime, you can induce a zinc deficiency. I believe that if we run out of nitrogen, then the plant may be more susceptible to other stress.

There are inoculants and other seed treatments which can improve plant health. One of these is the "Optimizer" seed treatment being used in the United States. Some Ontario people scoff at this seed treatment, but the grower who got 155 bushels an acre of soybeans this year used this seed treatment. He said that the treatment gave bigger roots. The unbelievers tried to discredit him because they could not believe that any seed treatment could give bigger roots.

As we go forward to produce higher yield, there will be more yield increases from unexplained treatments. The trick will be to sort out the snake oil from the true treatments. If a large number of growers are doing it year after year, there is probably a benefit, even if the learned scientific community cannot explain it.

I am still waiting for this learned community to explain electricity. You certainly cannot see electricity. But you can see its results. BF

Pat Lynch CCA (ON) is head agronomist for Cargill in Ontario.