Genetic Composition of Heterosis in F1 Rice Hybrid

Abstract

Utilization of heterosis in rice has contributed tremendously to the increase in rice productivity. There have been ranges of studies in many aspects of heterosis. But the key of genetic component of heterotic performance in crop hybrid is still uncharacterized. In this study, dissection of genetic composition of F₁ rice hybrid in traits in traits has been made : for culm length, yield components, grain amylose and grain anthocyanin. CRD comparative data was used between F₁ populations derived from 2 combinations: (elite F₈ non-glutinous purple lines combined x PPT1) and elite F₈ non-glutinous purple rice lines x KDML 105 with their 2 male-parents. The experiment was conducted with replicated pot yield trial at the Faculty of Agriculture, Chiang Mai University during 2010. Heterotic percentage was calculated as the relative of F₁ mean to the mid-parent value. The results showed that the genetic component varied among traits. Additive gene effect was achieved for culm length and 1,000 grain weight. Number of tiller and panicle per hill were negative dominance. Percent of filled grain was overdominace for lower parent. While both additive and positive dominant effects were the genetic component of grain amylose  and anthocyanin contents. This results provided adequate genetic basis of hybrid heterosis in rice regarding selection for improving the traits.