Studies on the Position of American Rice Varieties in Heterotic Utilization in F_1 Hybrid of Rice
Li Zichao;Wang Xiangkun;Wang Jianping;Huang Yanhong(Beijing Agricultural University. Beijing )
The analysis of the heterotic effect of F1 between the American rice (A ) and the Indica type(H ) or the Japonica type(K ) showed that the heterotic effect of most studied charaters in cross A ×K was close to. but lower than that of H ×K. Grain yield per plant, panicle number per plant and spikelet number per main panicle all showed highest heterosis, and were found usable in rice production. The heterosis in plant height was also high, but unusable. The heterosis in grain yield per plant showed close relationship with comptibility of the American rice.In A×K, the heterosis in grain yield per plant and panicle number per plant was highest, and the heterosis of F1 in A ×K tended to be similar to in K ×K. The 1000-grain weight had lower positive heterotic effect in both A ×H and A ×K. Furthermore. the test results indicated that the crosses between WCVS of the American rice and Indica and between American rice and Japonica were better models of high yield combination in rice heterotic utilization. and that A ×K was more practical.