Building resistance one plant at a time——Fred Bourland tracks plant bug resistance in breeding lines of cotton
"一株一抗" ——追踪棉花育种品系的抗虫性
- 关键词：
- 来源：
- FarmProgress
- 类型：
- 前沿资讯
- 语种：
- 英语
- 原文发布日期：
- 2025-04-23
- 摘要：
- Fred Bourland has been evaluating tarnished plant bug resistance in cotton breeding lines at the Northeast Research and Extension Center near Keiser, Ark., since before 2003. That’s a lot of cotton and plant bugs.When Bourland says varieties containing the ThryvOn technology “were very impressive” in their performance in his trials at the Northeast Research Center in 2023 and 2024, it’s based on years of experience.ThryvOn varietiesBut Bourland had a caveat: In 2024, the test had 16 ThryvOn varieties. Twelve of those ranked in the top varieties for boll loads in the tarnished plant bug tests. Of the other four, some were ranked considerably lower in the test.“So ThryvOn is not a silver bullet,” said Bourland. “But some of the varieties have stayed very consistent.”Bourland’s work with developing improved cotton varieties goes back more than the 20 years included in the presentation to include testing them for resistance to both tarnished plant bugs and boll weevils.He remembers the work of researchers including Bill Meredith with USDA’s Agricultural Research Service and Marion L. Laster with Mississippi State University at the Delta Research and Extension Center in Stoneville, Miss., in the 1960s, 70s and 80s.“They would take different lines and put them in large plots, side-by-side, treated and untreated, and see which ones in the untreated would do well,” he said. “Typically, they would use buffers planted with mustard in between those to serve as host plants for plant bugs. Then they would terminate the mustard to force the insects to move to cotton.Related:Supply and demand shifts leave cotton farms grasping for traction“I remember Bill Meredith presenting a paper at the Beltwide Cotton Conferences one year where he talked about being able to really cut the mustard, a reference to this tarnished plant bug work where they encouraged the plant bugs to move to the cotton.”Large plotsUsing large plots may still be the defining way to identify resistance to tarnished plant bugs, he said. “But how many varieties can you test at a time with these larger plots? With 20 or so entries that’s a big commitment. We’ve averaged looking at close to 100 different varieties or breeding line a year in our small plot work.”In the early days of his research, scientists had to be able to distinguish between insect damage caused by boll weevils and by tarnished plant bugs.“The first two years we used mustard, similar to what they did at Stoneville,” he said. “But mustard is a species that is difficult to manage out in a cotton field. So, we went to an early maturing frego-bract cotton, instead.”Frego bract, a mutant trait where the bracts surrounding the flower buds and bolls are long, narrow, twisted and tend to curl outward, exposing the square or boll, is another bit of cotton history associated with northeast Arkansas.It was discovered by a farmer named Frego, who observed it in a field of Stoneville 2B cotton on his farm about 20 miles from Keiser in the 1940s. He picked the cotton from the boll, ginned it by hand and planted the seed in his garden. The cotton that came up retained the trait, and Mr. Frego grew more of it. He told a county agent about it, and it eventually made its way to USDA researchers at Stoneville.“One thing we’ve learned is you don’t have to encourage the plant bugs in our area to get them to move to the plots,” Bourland noted. “They are there. And, really, the mustard was used back before boll weevil eradication. They were spraying for boll weevils and bollworms and controlling plant bugs with those sprays. They had to do something to encourage them, but we don’t have to do that.“I still plant the buffer of frego-bract – it helps separate the test. We like to plant it and three or four weeks earlier than we plant the plant bug test plots. We typically don’t use any insecticides for tarnished plant bugs. We did make one application this past year because they were just overwhelming our whole test.”Pest controlBoll weevil eradication meant that farmers and researchers no longer had to contend with the pest. But it also meant the elimination of some of the boll weevil sprays that had helped control tarnished plant bugs.When Bourland began looking at cotton varieties for resistance solely to tarnished plant bugs in 2003, he started slowly because of the amount of manhours involved in plant sampling and determining boll loads to gauge the impact of the pest.“In 2006, Cotton Incorporated started supporting some of this work, and we expanded to variety tests and regional tests,” he said, “And, over the years, we have looked at a total of 2,724 lines in 102 tests. If you multiply that, that’s over 26,000 plots. So, it has been a large effort.“One lesson we have learned is we don’t have to have large plots. We can separate lines based on their performance in these short one-row plots. And I think that by using boll load ratings we can go to less than eight replications.”
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- 171
