GENETIC-ANALYSIS OF THE RICE CULTIVAR KASALATH WITH SPECIAL REFERENCETO 2 PHOTOPERIOD SENSITIVITY LOCI, E-1 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 molecular genetics of heading time in rice, we pe rformed a genetic analysis of KA with special reference to two major p hotoperiod sensitivity loci, E-1 and Se-1. We also discussed the relat ionships of these two loci with the five QTLs (Hd-1 similar to Hd-5) t hat Yano et al. (1995) identified using the progenies from the cross ' KA x the Japanese japonica cultivar Nipponbare'. The F-1 and F-2 gener ations from the crosses '11 heading time tester lines x KA' were subje cted to genetic analyses. The Re (brown pericarp and seed coat) and Pg i-2 (phosphoglucose isomerase-2) loci were used as linkage markers of the E-1 and Se-1 loci, respectively. Experimental results showed that KA carries a new photoperiod sensitivity allele E-1(k)(t) and a photop eriod insensitivity allele Se-1(e). The E-1(k)(t) proved to stimulate the photoperiod sensitivity of rice more than a strong photoperiod sen sitivity allele E-1. Based on the findings of the present study and pr evious works, we concluded that the E-1 and Se-1 loci were identical w ith the Hd-4 and Hd-1 loci, respectively.