There is bell ringer-type news for cotton growers who rotate with soybeans. A small flock of soybean varieties resistant to reniform nematodes has been identified.
Reniform nematodes currently aren't one of the bigger problems in soybeans, but they're an increasingly serious one in cotton. Previously, only a few soybean varieties were identified as resistant to the nematodes.
University of Arkansas plant pathologists conducted a study to find if a pool of soybean varieties was available for rotation with cotton on fields infested with reniform nematodes.
The scientists screened 288 varieties to find those with good reniform-nematode resistance. Of the 288 lines, 13 proved more resistant than Forrest, the standard for reniform-resistant soybean varieties. Hartwig is also resistant.
"These were all entries into the Arkansas Variety Testing Program or the Mississippi Variety Testing Program," explains Robert Robbins. Robbins headed the plant pathologist research team that included Larry Rakes and Larry Jackson.
"We've been waiting for this research for years," says Grover Shannon, a soybean breeder with Deltapine Seed. "I cannot tell you how many times in the last five years I've been asked, 'Do you have any soybeans resistant to reniform nematodes to rotate with cotton?' "
"This is highly worthwhile information for cotton growers," Robbins agrees, "because they have been looking for something to rotate with. If they knew they had reniform problems in cotton, most really didn't know there were resistant soybean varieties they could rotate with."
In cotton, reniform nematodes are a serious problem that's worsened over the last 10 or so years, according to Robbins. It has been expanding northward.
"Nematodes can be a very bad problem in cotton," Robbins says. "I know of one farmer's field, for example, that over a period of time went from over two bales of cotton down to half a bale. It turned out they had a tremendous reniform nematode population and just thought it was some other problem. They never thought about reniform nematodes."
Robbins and his team plan to screen all new entries in the Arkansas and Mississippi soybean variety tests again this year. Since there is about a one-third turnover each year in the entries, they hope to identify more varieties with good reniform-nematode resistance.
The screening research project was made possible with soybean checkoff funds from the Arkansas Soybean Promotion Board.
The 13 varieties in the screening that proved more resistant than Forrest were: Delsoy 5710; S94-1956 (University of Missouri); Terral TV4770; NK S53-Q7; SC91-2007 (Clemson); Riverside Robin-5; Deltapine DP 5806RR; Accomac; AgriPro AP 588RR; Terral TV 5797; Hartz H5181RR; HBK R5411; and Eagle Seed ES 48N.