RENlon and Its Effects on Agronomic and Fiber Quality Traits in Upland Cotton

Cotton (Gossypium spp.) is attacked by several species of parasitic nematodes including the reniform nematode (Rotylenchulus reniformis Linford and Oliveria). Qualitative resistance (gene symbol RENlon) was discovered in a wild cotton relative (Gossypium longicalyx J. B. Hutch. & B. J. S. Lee), transferred to an upland (Gossypium hirsutum L.) background, and released as two sister germplasm lines, LONREN-1 and LONREN-2. In 2010 and 2011, we tested 20 homogeneous resistant and 20 homogeneous susceptible F-2:4 and F-2:5 lines from the cross LONREN-1 x Fibermax 966 in two fields, one infested with reniform nematode and one not infested. The objective was to determine the effect of RENlon on cotton yield, agronomic traits, and fiber quality in a nematode-infested and a nematode-free environment. Lines with RENlon were stunted during early season growth and yielded less than did their sister lines null for RENlon in the nematode-infested field. At-harvest nematode populations were reduced in plots where lines with RENlon were planted. There were no yield differences between lines with and without RENlon in the nematode-free field. Fiber quality was affected by RENlon, with lines carrying the gene tending to have greater fiber strength, better length uniformity, and lower short fiber content. The RENlon gene is effective in reducing nematode populations and may improve fiber quality; however, the LONREN-1 progenies did not reduce yield losses from reniform nematodes.