Abstract
The presence of semi-sterile panicles in Indica-Japonica crosses of rice is due to an allelic interaction at a gamete abortion locus, S-5 on ( hromosome 6 The S 5 n allcle s referred to as wide compatibility gene" (WCG), since one of the parents carrying this allele does not show hybrid sterility in the Fl' However. Ketan Nangka, which is a donor of S-5 n, sholved typical h.vbrid sterility when it was crossed to local varieties from Taihu Lake, such as Fengjingdao and Feilaifeng, as weil as to those from Yun-nan Provinco, sueh as Dabai, Luanjiaolong and Xiaobaigu. A new locus for the sterilitv in the hvbrid between Ketan Nangka and the local varieties was detected near the Est-5 locus on Chromosome 1, and designated as S-16 following our recent report.s on S-7, S-8 . S-9 and S-15 .
