Genetic effect on amylose and protein contents in the crossed rice [Oryza sativa] seeds

The nature of gene action may be revealed and desirable parents may be found by analyzing the combining ability and estimating the degree of heterosis in an early generation. Currently, varieties with a good eating quality are preferred. This study was carried out to obtain information on the action of genes using the analysis of variance components estimated by minimum norm quadratic unbiased estimation (MINQUE(1)) and to estimate the genetic effects on amylose and protein contents, as criteria for selection of good eating quality by adjusted unbiased prediction (AUP). The mean values of amylose content, protein content and grain yield in the parents were 18.4%, 7.78% and 19.8 g plant-1, respectively, and those in crossed F1 seeds were 17.4%, 10.8% and 23.6 g plant-1, respectively. The effects of additive were significant for both amylose and grain yield, but not for protein content, indicating the importance of the additive gene action on amylose content and grain yield. The effects of dominance were highly significant for amylose content, protein content and grain yield. Especially, the effect of dominance was greater than that of additive on protein content. The effect of maternal was detected in only amylose content, and L 42 and L 53 showed significant and negative maternal effect on amylose content. Ansanbyeo, Hinohikari, L 42 and L 53 exhibited negative additive effects on amylose content, which suggested the possibility of a decreased amylose content in their crossed progenies. Mid-parent heterosis for amylose content ranged from \44.7% (L 42 X Hinohikari) to 32.9% (L 53xLemont) with an average value of \7.2% for all crossed F1 hybrids. However, all of the crossed seed showed positive mid-parent heterosis for protein content in this study and the differences were not significant among the hybrids.