Mapping QTLs for drought resistance at seedling stage in rice by using a doubled haploid population.

The QTLs for drought resistance at the seedling stage were analyzed by using a doubled haploid (DH) population consisted of 251 lines from the cross between a japonica parent Maybelle and an indica parent Baiyeqiu. A genetic linkage map with 226 SSR markers was constructed. Through single-locus analysis following composite interval mapping (CIM),a total of 5 QTLs were detected on 5 different chromosomes. Four QTLs were also detected by two-locus analysis,which resolved 4 epistatic QTLs (E-QTLs). The additive genetic effects of all QTLs were positive,indicating the alleles from Baiyeqiu improve drought tolerance of the DH population.