Mapping of QTL Controlling Low-temperature Germinability in Rice

A recombinant inbred line population derived from a japonica/indica cross were assessed for low-temperature germinability by germination tests at 15°C.Together with a linkage map consisting of 198 marker loci,the main-effect QTL for the trait were mapped via composite interval mapping.A total of 7 QTL for the trait were identified,which were mapped to chromosomes 1,3,5,6 and 8,respectively.These QTL individually explained 5%-16% of the phenotypic variation.Two QTL with the largest effects on the trait were QTL qLTG-3-2 and qLTG-8-1 which were located to the interval RM148-RM85 of chromosome 3 and the interval RM223-RM210 of chromosome 8,respectively.The effect of QTL qLTG-3-2 decreased gradually during (6-10) days after inoculation while that of QTL qLTG-8-1 increased gradually during 9-14 days after inoculation.Although so,however,the effect directions of these two QTL were kept consistent during the whole germination process.The positive allele at QTL qLTG-3-2 came from the parent Teqing while that at qLTG-8-1 from the parent Lemont.These two alleles would be used as potential targets in genetic improvement of low-temperature germinability via marker-assisted selection in rice breeding.