Abstract:

【Objective】 Late blight is a worldwild disease in tomato and can cause serious yield loss. Through construction of tomato molecular genetic map and QTL analysis of gene cluster ph-3 to find closely linked molecular markers. This will provide a theoretical and practical basis for molecular marker-assisted breeding. 【Method】 L3708（L. pimpinellifolium）accompanied with resistant gene cluster ph-1,2,3 was used as male parent and 04968（L. esculentum）susceptible race with good characters as female parent, the 260 F2 single plants as construction population, a molecular marker linkage map composed with 12 linkage populations was constructed by SSR and AFLP molecular marker. QTLs were found by applying complex-space mapping and according to seedling-inoculated tomato’s resistant response to Phytophthora infestans physiological stains T1, 2. 【Result】 The map includes 3 SSR markers and 149 AFLP makers. And the map coveres 1 443.07 cM of the whole genome. The average space between markers was 9.50 cM. Five QTLs correlative to ph-3 were found. Qph3-1 was on the first chromosome, explainable phenotype variation was 26.59%. Qph3-2 was on the sixth linkage population and the explainable phenotype variation was 54.86%. Qph3-3, Qph3-4, Qph3-5 were on the ninth linkage population and the explainable phenotype variations were 9.24%, 10.27%, and 36.49%. The genetic effect of QTL loci was additive and dominant. 【Conclusion】 The 5 QTL screened in this study can be used as a tool for molecular marker-assisted breeding.

Key words: tomato, genetic linkage map, SSR, AFLP, resistant gene cluster ph-3, QTL