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Reniform Nematode Research Proves Invaluable

Christi Short

Christi Short
Rochester, Texas

Many factors can impact cotton yield — variety, weather and soil type are a few. But pests and insects are always a problem across the country. One pervasive pest that is no stranger, no matter where you live, is the nematode, specifically the reniform nematode.

The reniform nematode is responsible for substantial yield loss across the Cotton Belt. Until this year, there were no commercially available resistant varieties. Growers have managed the pest using chemical applications and crop rotations.

But the reniform nematode continues to increase and spread. Reniform nematodes can survive in the soil without a host plant for roughly two years. When a host plant is reintroduced, populations skyrocket.

Research Results

The 2021 planting season brings the opportunity to buy and plant recently released cottonseed varieties with genetic resistance to reniform nematodes. The effectiveness of these varieties compared to non-resistant varieties shows tremendous yield increase. Thanks to essential funding from The Cotton Research and Promotion Program for current Texas research projects, scientists are able to evaluate the new varieties.

Dr. Reagan Noland and graduate student, Jennifer Dudak, with Texas A&M AgriLife Extension, focused on the new opportunity for growers and explored how the new varieties could benefit reniform-infested fields. One belief that has emerged over the years is that genetic resistance spans different nematode species.

Dudak’s research shows that is not the case. She evaluated root-knot-resistant varieties, reniform- resistant varieties, and a nematode-susceptible variety for yield performance. Her results show a variety with no resistance to nematodes performs similarly to root-knot-resistant varieties when placed in a field with reniform nematode pressure. However, she observed the reniform-resistant varieties’ yields were unmatched.

“My research and analyses show that reniform nematodes are one of the most detrimental and costly pests to cotton growers today,” Dudak says. “In 2019, yield loss and crop damage from nematodes cost U.S. cotton growers about 62 million dollars.

“One big piece of this nematode puzzle was determining that cotton varieties with root-knot nematode resistance did not perform differently than a nematode-susceptible variety. Research showed that nematode genetic resistance is specific to the pest, and that’s key for growers moving forward.”

Increased Profitability

With this concept proven, researchers can now focus on the reniform-resistant varieties and the effect they can have on profitability. Testing commercially available varieties showed that in a field with pervasive reniform infestation, using the new varieties can increase yield up to 45% per acre on average, compared to non-reniform-resistant varieties, according to Noland and Dudak’s work.

stunted cotton

A severe new infestation of reniform nematodes results in stunted cotton.

“Considering the increased yield and the closing price of cotton in 2020, this genetic resistance represented an average $200-per-acre increase across environments,” Noland says. “The development and release of these reniform resistant varieties will bring great benefit to cotton producers. We are thrilled to coordinate this research and generate valuable information for the industry.”

Noland and Dudak’s research is an example of how the program is working to increase on-farm profitability. Cotton Incorporated, through the State Support Program in Texas, funded this research over the past two years to quantify the value of the new varieties and inform variety selection decisions for growers.

Cotton Incorporated’s investment in battling the reniform nematodes started in the mid-1990s when program funds were first invested to reniform nematode research management. In 2001, they began to identify resistant traits, with molecular level work and research taking place years later.

“Pursuit of reniform nematode resistance is just one example of the long-term investment and collaboration between Cotton Incorporated, the U.S. Department of Agriculture, universities, Extension agents and seed companies to improve the profitability of cotton growers across the Cotton Belt,” says Dr. Gaylon Morgan, director of agricultural and environmental research at Cotton Incorporated.

Environmental Benefits

Morgan says the new nematode-resistant varieties can improve the environmental footprint of cotton in infested fields. Historically, a grower was limited to expensive chemical options to suppress early season nematode pressure in the field.

With the success of the new nematode- resistant varieties, chemical applications will not need to be made and will save growers money. It’s also important to note that the varieties are comparably priced to non-resistant varieties, according to current pricing listed online by Plains Cotton Growers.

“This project shows how valuable program and research partnerships are for the on-farm profitability and improvements for the U.S. cotton grower,” Morgan says. “It’s great for the growers to see years of molecular and breeding work come to fruition when we can offer a tangible product to be used on the farm, like the release of these varieties.”

Christi Short is the Cotton Board’s regional communication manager for the Southwest. Contact her at cshort@cottonboard.org.