Detecting molecular markers associated with heat tolerance of Chinese cabbage

A genetically stable population of recombinant inbred lines (RIL) was derived from a cross between a heat tolerant line 177 and a heat sensitive line 276 of Chinese cabbage (Brassica campestris L. ssp. pekinensis ) using single seed descent. The RILs were analyzed using isozyme, RAPD and AFLP techniques in order to find molecular markers that are linked to heat tolerance quantitative trait loci (QTL). The results of variance analysis of single factor indicated that there were 9 molecular markers closely linked with heat tolerance QTL, including five AFLP markers, three RAPD markers and one PGM isozyme marker. Total genetic contribution of these makers to heat tolerance was 46.7%. Five of the nine markers distributed in one linkage group, the remaining four markers were located in separate groups. Thus the nine heat tolerance linked markers distributed in five independent locations in the genome of Chinese cabbage.