One reason is a projected additional 220 million bushels of soybeans a year for American farmers to sell on the domestic and international markets. That's the number of bushels robbed each year by just one soybean pest, the soybean cyst nematode. Cregan's goal and that of a number of other soybean researchers is to identify genes that will provide resistance to the soybean cyst nematode so the resistance can be bred into commercial soybean varieties. Cregan has completed the development of mapping markers for the first two of the four genes he thinks are responsible. He's continuing work with colleagues at the University of Minnesota to find markers for the remaining two resistance genes.
Potential gains are huge for American farmers.
The extra 220 million bushels is just for starters. Throw in another few hundred million bushels for other pests the soybean might also resist, were a complete genome map available to plant breeders. And yet another 200 million bushels or so could be harvested, were genes found to raise soybean yields 2 or 3 bushels an acre over America's typical yearly plantings of 75 million acres. Cregan and his colleagues are hoping to find DNA fragments from the wild ancestor of soybean that could induce such a yield increase in commercial soybeans. He and the Nebraska team have developed over 300 lines of soybeans that have one-eighth of their genomes replaced by DNA fragments from the wild ancestor of soybeans.