Association of the Resistant Gene with Simple Sequence Repeat Markers to Meloidogyne incognita in Cucumis sativus-hystrix Introgression Line

The southern root-knot nematode (RKN), Meloidogyne incognita Kofoid and White (Chitwood) is one of most destructive species of plant parasitic nematodes, which causes significant economic losses to cucumber (Cucumis sativus L. 2n=2x=14) production worldwide. No RKN-resistant was found in current cucumber cultivars so far. An F2 segregation population of 344 plants was developed from a cross between a resistant introgression line (RIL) and a susceptible introgression line (SIL) to RKN, both were derived from the interspecific hybridization between the wild species Cucumis hystrix Chakr. (2n=24, HH) and cultivated cucumber. Thirty-three parental polymorphic markers were identified through screening 1055 SSR markers (polymorphism 3.13%). A linage group with 12 makers was constructed, and two quantitative trait loci (QTLs) on Chromosome 6 were determined with interval mapping analysis, explaining 28.5% and 22.2% of the phenotypic variation respectively. Our result is the first report which focus on the RKN-resistance QTLs mapping in cucumber. In short, the determined SSR markers will facilitate the marker-assisted selection of resistance to RKN in cucumber breeding and can be used for further genetic study and genetic map construction.