|Bell, Alois - Al|
Submitted to: Journal of Plant Registrations
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/12/2013
Publication Date: 3/7/2014
Citation: Bell, A.A., Robinson, A.F., Quintana, J., Dighe, N.D., Menz, M.A., Stelly, D.M., Zheng, X., Jones, J.E., Overstreet, C., Burris, E., Cantrell, R.G., Nichols, R.L. 2014. Registration of LONREN-1 and LONREN-2 germplasm lines of Upland cotton resistant to reniform nematode. Journal of Plant Registrations. 8(2):187-190. Interpretive Summary: The reniform nematode is an increasingly important pest causing yield losses of 268,698 bales in the U.S. in 2012. No cotton cultivar currently has appreciable resistance to the nematode. However, a wild cotton in Africa is considered immune because it does not support reproduction of the nematode. ARS scientists in cooperation with scientists from Texas AgriLife Research, Louisiana State University and Cotton Inc. transferred the resistance character from the wild cotton into Upland Cotton lines called LONREN-1 and LONREN-2. In controlled tests, the LONREN lines have reduced nematode numbers on the soil by 95 percent or more. They also are very effective in controlling nematodes in the field but, unfortunately, have shown significant stunting and yield loss from fungal root rots when the nematode is present. The lines have been registered and released to the public. Further breeding might separate the resistance to nematodes from the increased susceptibility to fungal root rots.
Technical Abstract: Cotton (Gossypium hirsutum L.) germplasm lines LONREN-1 (Reg. No. GP-977, PI 669509) and LONREN-2 (Reg. No. GP978, PI 669510) were developed and released by the USDA-ARS, Texas Agricultural Experiment Station and Cotton Incorporated in 2007 to provide breeders with desirable germplasm resistant to the reniform nematode (Rotylenchulus reniformis Linford and Oliveira). The resistance was transferred from wild G. longicalyx via a triple-species hybrid. Crosses, backcrosses, and single plant selections were used to develop the F2 progeny used for seed production. Resistance was followed with the codominant simple sequence repeat BNL 3279_114 marker, located 1.4cM proximal the phenotypic marker 'greenfuzz' (LTCOL_F) located 4.5 cM distal to the Renlon resistance gene on chromosome 11. A single nucleotide polymorphism marker also was developed for rapid screening of large numbers of seed. The introgressed chromosome segment is smaller in LONREN-2 than in LONREN-1. Both lines reduced reniform populations by 95% in growth chamber bioassays and by 50 to 90% in fields. In the absence of nematodes in the field, growth rate, yield, and fiber quality of the lines were similar to that of the 'Fibermax 958' parent. In the presence of reniform nematodes in the field, the lines often showed stunting and yield losses, probably due to enhanced severity of fungal seedling diseases, especially Thielaviopsis root rot. The seedling diseases in LONRENs were diminished by control measures such as fungicides, nematicides, and crop rotation with corn or sorghum, and were negligible in a second year of planting in the same field.