Genetic Analysis of the Rice Cultivar Kasalath with Special Reference to Two Photoperiod Sensitivity Loci, E1 and Se-1

The indica rice cultivar Kasalath (KA) has been extensively used as a model cultivar in the molecular genetics of rice in Japan. To advance our knowledge of the nrolecular genetics of heading thrre in rice, we performed a genetic analysis of KA with special reference to two major photoperiod sensitivity loci, E1 and Se-1. We also discussed the relationships of these two loci with the five QTLs (Hd-1∼Hd-5) that Yano et al.(1995) identified using the progenies from the cross‘KA × the Japanese japonica cultivar Nipponbare'.The F1 and F2 generations from the crosses ‘11 heading time tester lines × KA' were subjected to genetic analyses. The Rc (brown pericarp and seed coat) and Pgi-2 (phosphoglucose isomerase-2) Ioci were used as linkage markers of the E1 and Se-1 Ioci, respectively. Experimental results showed that KA carries a new photoperiod sensitivity allele E1 k(t) and a photoperiod insensitivity allele Se-1e. The E1k(t) proved to stimulate the photoperiod sensitivity of rice more than a strong photoperiod sensitivity allele E1. Based on the findings of the present study and previous works, we concluded that the E1 and Se-1 Ioci were identical with the Hd-4 and Hd-1 Ioci, respectively.