Inheritance analysis of anther dehiscence as a trait for the heat tolerance at flowering in japonica hybrid rice ( Oryza sativa L.)

We analyzed the heredity of anther morphology in rice ( Oryza sativa L.) using incomplete diallel crosses of six japonica restorer lines and eight cytoplasmic male-sterile (CMS) lines, and 48 F 1 combinations resulting from these crosses. We analyzed four traits: the length of dehiscence formed in the apical (ADL) and basal (BDL) parts of the anther and the respective widths, ADW and BDW. The ratios of V gca (variance of general combining ability) to V sca (variance of specific combining ability) were 8.0 for BDL, 1.4 for BDW, 3.0 for ADL, and 2.8 for ADW. Narrow-sense heritability ( H N 2 ) was 76.5 % for BDL, 37.9 % for BDW, 66.0 % for ADL, and 65.9 % for ADW. The effects of GCA (general combination ability) for BDL ranged from −67.0 to 68.9 μm (CMS lines) and from −33.4 to 43.0 μm (restorer lines); those for ADL were −46.7 to 44.0 μm (CMS lines) and −29.5 to 34.0 μm (restorer lines). We conclude that BDL and ADL have high heritability, and we can modify the size of apical and basal dehiscence by selecting suitable CMS and restorer lines.