二面交雜에 依한 米粒重의 遺傳分析 및 米粒形質 相互間의 關係

Diallel Analysis of Grain Weight and Inter-relationships between Components of Grain Size

Yield of rice is generally determined by four components such as number of panicles, number of grains per panicle, grain weight, and ripening ratio. Remarkable increase in yield of recently developed “Indica × Japonica” rice varieties mainly depended on higher number of panicles per hill and higher number of grains per panicle as compared to those of “Japonica × Japonica” varieties. However, contribution of those factors to yield will reach to the limit at certain point of time. Grain weight is presumed to be another possible factor for sharp increase of yield. Diallel crosses were made to analyze the genetic characteristics of grain weight. This study was agreed with previous reports that grain weight is a kind of polygenic character. It was assume that breeding for large grain will be rather more difficult than for small grain judging from the fact that no transgressive segregation was found toward large direction.