Genetic Components and Correlation Coefficient for Earliness and Grain Yield in Rice
The present research was conducted to study earliness and their correlations with grain yield in rice breeding. It was carried out during 2012 and 2013 growing seasons at RRTC Farm, Sakha, Kafr El-Sheikh, Egypt. F1 were evaluated along with their parents for genotypic variation. ANOVA revealed significant differences at the 0.01 level among crosses and parents as well as between parents and crosses. These results indicated a wide range of variations among parental groups. The mean squares of parents vs. crosses were found to be significant for all grain yield and its component characters. Variance among crosses indicated significant SCA effects at the 0.01 level for all its component traits. Concerning GCA effects four entries; Sakha 101, Novator, Anait and Large Stigma exhibited positive significant estimates at 0.01 levels for grain yield /plant. The desirable hybrid combinations Giza 179 X Large Stigma and Sakha 105 X VNIRB 572 exhibited significant values of SCA effects at 0.01 and 0.05 levels for grain yield. Heritability estimates in narrow sense ranged from low to moderate. Sakha 101 X Novator, Sakha 106 X Novator and Giza 179 X Large Stigma were the promising hybrid combinations for improving yield character according to results for mid and better parent heterosis. Positive significant correlation coefficient at 0.01 level was recorded between 1000-grain weight and grain yield/plant. The four earliness component traits understudy contributed directly to the earliness character. Also, the earliness component traits; days to heading, days to maturity and elongation of panicle initiation had a direct contribution to yield component.