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Annual losses to aflatoxin are estimated at some $190 million. Paul Williams, USDA-ARS researcher/geneticist, and his Mississippi-based team are learning to combat the disease through corn breeding and molecular markers.
Williams’ team saw success with two lines — Mp715 and Mp717 — in 2008 trials. Another line, Mp04:97, did well in 2009 trials. Mp715 and Mp717 have been released to numerous university and commercial breeding programs.
“We will likely release Mp04:97 after we review this year’s aflatoxin contamination data.
“When we release lines, they’ll be used by both commercial and public research institutions. Unfortunately, with corn we can’t really keep track with the germplasm after it’s publicly released.
“I do know that commercial companies have used it in their breeding programs. But as far as which lines end up in which hybrids on the market, we don’t know. Some of the company people have assured me that the better job we can do and get them good, molecular markers for resistance, the more likely they are to put resistance into commercial hybrids.”
When releasing a new variety, getting the balance right is difficult. “When someone buys hybrid seed for the farm, they don’t want aflatoxin contamination. But there are a lot of things they do want: high yields, lodging resistance, grain quality, and other things. Resistance to aflatoxin contamination is only one component of a desirable seed.”
Williams is also researching lines resistant to fall armyworms and corn borers.
“Of course, with the advent of Bt there’s been less interest in the native resistance in developing commercial hybrids. Bt did such a great job of controlling corn borers and some did quite well with fall armyworms.
“Even so, we’ve continued work on insect pests. There are still times when you’d like to have native resistance instead of the transgenics.”
And there’s a link between insect damage and aflatoxin.
“We feel that some work on insect resistance could contribute to lessening the aflatoxin problem. Experiments show that in a year when aflatoxin can be a problem, insect damage can make it even worse.”
The solution to aflatoxin is coming, says Williams.
“I hope the readers will think what we’re doing is worthwhile and know we’re tackling the problem. We think the genetics approach will be an important component to reducing the likelihood of an aflatoxin problem. We feel using both conventional breeding methods and molecular markers will yield fruit and that’s the right way to go.”