Location: Crop Genetics ResearchTitle: Rotylenchulus reniformis resistance in Gossypium arboreum accessions Author
Submitted to: Journal of Nematology
Publication Type: Abstract Only
Publication Acceptance Date: 7/24/2018
Publication Date: 12/1/2018
Citation: Stetina, S.R., Erpelding, J.E. 2018. Rotylenchulus reniformis resistance in Gossypium arboreum accessions. Journal of Nematology. 50(4):658.
Technical Abstract: Reniform nematode (Rotylenchulus reniformis) causes annual yield losses of 4 to 8% in upland cotton (Gossypium hirsutum) in the southeastern United States. Host plant resistance is a desirable management option, but no upland cotton cultivars have been identified with resistance. Resistance has been reported in related cotton species, and Gossypium arboreum germplasm may be an important source of genetic diversity for resistance. Thus, 226 G. arboreum accessions from the US germplasm collection were evaluated for their reaction to the nematode in growth chamber experiments. Due to growth chamber space constraints, accessions were divided into 3 sets of 74 to 76 entries for evaluation. Each set of accessions was tested twice, and data from both tests were combined for analysis. Each set included the resistant controls Gossypium barbadense TX110 and G. arboreum accession A2-190 (PI 615699) and the susceptible controls G. hirsutum cv. Deltapine 16 and G. arboreum accession A2-101 (PI 529729). Root infection was measured on 3 plants per accession 4 weeks after inoculation with 1,000 vermiform nematodes and data were expressed as females per g of fresh root tissue. Data were subjected to log10(x+1) transformation prior to analysis of variance, and differences among genotypes were determined using differences of least squares means (P less than or equal to 0.05). Additionally, a nematode index calculated for each entry (percentage of the average number of females that developed on susceptible G. hirsutum cultivar Deltapine 16) was used to classify accessions as resistant (nematode index <10%), moderately resistant (10% to 30%), moderately susceptible (31% to 60%), or susceptible (>60%). In total, there were 16 resistant, 125 moderately resistant, 72 moderately susceptible, and 13 susceptible accessions identified. Six accessions supported significantly fewer reniform nematode infections than were observed on the resistant checks: A2-690 (PI 616184), A2-737 (PI 616231), A2-814 (PI 616308), A2-849 (PI 616434), A2-860 (PI 616354), and A2-995 (PI 629323). Cotton breeders would benefit from introgressing the resistance from these newly-identified resistant accessions into their upland cotton improvement programs.