Gossypium arboreumAccessions Resistant toRotylenchulus reniformis.
In the southeastern United States, reniform nematode (Rotylenchulus reniformis) is a serious pest of upland cotton (Gossypium hirsutum), a species which has no naturally occurring resistance against this nematode. To identify sources of reniform nematode resistance in species closely related to upland cotton, 222G. arboreumaccessions from the U.S. germplasm collection were evaluated in repeated growth chamber experiments. In initial screenings, root infection was measured 4 wks after inoculation. The 15 accessions supporting the fewest infections (PI 529992, PI 615755, PI 615766, PI 615788, PI 615848, PI 615856, PI 615950, PI 615977, PI 615991, PI 616008, PI 616016, PI 616062, PI 616126, PI 616159, and A2 553) were evaluated again in confirmation tests lasting 8 wk. The combined totals of nematodes extracted from soil and eggs extracted from roots were analyzed. All 15 accessions tested supported significantly smaller reniform nematode populations than the susceptible controls (G. hirsutumcultivar Deltapine 16 andG. arboreumaccession PI 529729). Nine accessions (PI 529992, PI 615755, PI 615766, PI 615788, PI 615856, PI 615950, PI 615991, PI 616008, and PI 616159) supported reniform nematode populations comparable to the resistant control (G. arboreumaccession PI 615699), and accession PI 615848 had significantly fewer reniform nematodes than the resistant control. Cotton breeders would benefit from introgressing the newly identified resistance from these accessions into their upland cotton improvement programs.
Research Plant Pathologist and Research Geneticist (Plants), USDA ARS Crop Genetics Research Unit, PO Box 345, Stoneville, MS 38776.
Salliana R
SR
Stetina
Research Plant Pathologist and Research Geneticist (Plants), USDA ARS Crop Genetics Research Unit, PO Box 345, Stoneville, MS 38776.
John E
JE
Erpelding
Gossypium hirsutum; cotton; reniform nematode; resistance