University of Georgia cotton research yields root-knot-nematode-resistant varieties

University of Georgia cotton breeder Peng Chee’s groundbreaking research in molecular genetics provides Georgia cotton farmers with root-knot-nematode-resistant cotton varieties. It also garnered Chee national recognition in January, when he was awarded the 2016 Cotton Genetics Research Award during the 2017 Beltwide Cotton Improvement Conference in Dallas.

Chee, a professor in UGA’s Institute of Plant Breeding, Genetics and Genomics, identified nematode resistance as a top priority when he started working on the UGA Tifton Campus in 2000.

“Host-plant-resistance research has been a high priority in my lab,” Chee said. “We were the first group to identify the genes involved in providing resistance to root-knot nematode in cotton.”

Chee published the genome location of the resistant genes in 2006, and private breeding companies now use this knowledge to develop a selection system to transfer the resistant genes into elite cotton varieties. Ten years later, there are now numerous nematode-resistance varieties available to cotton growers.

If infected by microscopic southern root-knot nematodes, cotton roots swell in response. The knots serve as feeding sites where the nematodes grow, produce more eggs and stunt the plant’s growth.

Breeding for resistance to nematodes increased in importance when some of the chemical treatment options that Georgia farmers used to combat the nematodes were slowly phased out. The Coastal Plain region is a hotbed for southern root-knot nematodes in cotton, Chee said. Depending on the year and environmental conditions, Georgia cotton crops could be vulnerable to a significant outbreak of nematodes.

Using nematode-resistant varieties might be the best course of action for some farmers, especially since about 70 percent of Georgia’s cotton fields are infested.

In addition to the nematode research, Chee’s work in the UGA Molecular Cotton Breeding Laboratory has centered on fiber quality, a trait he considers essential if the U.S. cotton industry is to compete with other cotton-producing countries and, more importantly, with synthetic fibers. One of the main goals of Chee’s lab is to explore wild cotton to identify fiber-quality genes currently not in the domesticated germplasm and to breed them into cotton varieties adapted for Georgia.

“The whole approach to cotton breeding has changed a lot in the last two decades. When I first started working at the Tifton Campus, cotton genomics was still in its infancy,” Chee said. “Our goal at the time was to develop a genomic toolbox for cotton breeders. I believe we are now starting to see new cotton varieties being developed through the use of these tools.”

While Chee’s work has been successful, he can’t help but think about the future of genetic research and where it could lead over the next decade.

“This is an exciting time to be in the field of cotton breeding and genomics. I have witnessed cotton breeding, transitioning from traditional phenotypic selection to selection of progeny based on what genes they carry by using DNA markers. The complete genome sequence of cotton has greatly accelerated our understanding of the genetic control of economically important traits such as insect and disease resistance as well as fiber yield and quality,” Chee said. “I suspect the next two decades will see a broad application of genomics in cotton breeding.”

For more information about the research conducted in the UGA Molecular Cotton Breeding Laboratory, see www.nespal.org/peng_lab.