Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: April 24, 2007
Publication Date: July 28, 2007
Citation: Roberts, P.A., Ulloa, M., Wang, C. 2007. Molecular markers and mapping of root-knot nematode resistance in cotton.. American Phytopathological Society Abstracts.
Host-plant resistance is economic and highly effective for root-knot nematode (RKN) Meloidogyne incognita control in cotton Gossypium hirsutum. Recently, nematode R gene mapping in cotton has revealed relationships between resistance sources and linked molecular markers. Markers are important for the efficiency of incorporating resistance genes into elite cultivars. Microsatellite markers (SSR) linked to RKN resistance in G. hirsutum Acala NemX were identified using segregating progenies and recombinant inbred lines from intraspecific crosses and an interspecific cross with G. barbadense Pima S-7. Informative SSR were mapped on the above populations and one co-dominant SSR marker CIR316 was identified tightly linked (2.1 to 3.3 cM) to a major resistance gene (designated rkn1). Additional markers allowed the rkn1 gene to be mapped to cotton chromosome 11. Other markers linked to rkn1 were developed from AFLP screening and converted to CAPS and SNP markers for high throughput screening. Subsequently, a similar location of the major resistance determinant present in the Auburn source of RKN resistance was reported, and additional non-linked minor QTL for resistance identified. Higher levels of resistance in cotton by transgressive segregation were obtained with factors contributed by susceptible parents in intraspecific and interspecific crosses. These gene relationships and use of markers for cotton improvement are discussed.