Genetic Analysis of Leaf Length and Width of Flag Leaf in Rice

Abstract

Since some distinguished differences in leaf characteristics were observed between the modern U. S. and oriental rice cultivars and leaf length and leaf width are remarkable leaf characteristics in modern rice breeding programs, a series of genetic studies was designed to tackle the genetic control of leaf characteristics for expanding the genetic diveristy. Genetic information about leaf length and width of flag leaf reported here was deduce by the components of variation and the ratios between components and diallel graph from a six-parent diallel cross of rice, according mainly to theory and analysis of diallel cross of Hayman. Results clearly indicated that both additive and dominance gene effects were important in differentiating the two flag leaf characteristics; however, it is evident that the genetic mechanisms of two characteristics studied were different. As to leaf length, dominance gene effects was significantly greater than those of additive, the overall measure of dominance of leaf length was overdominance, and the direction of dominance was ambidirectional. On the other hand, dominance gene effects on controlling leaf width was unimportant than additive gene effects, the mean degree of dominance of leaf width was partial or incomplete, and the direction of dominance was toward relatively wider flag leaf.