Selection Index for Yield and Yield Contributing Traits in Improved Rice Genotypes

抄録

To select improved rice lines according to a selection index, a field experiment was conducted using fifty improved rice genotypes, during the dry season of 2017 at the Department of Plant Breeding, Physiology and Ecology, Yezin Agricultural University, Myanmar. The examination used a Randomized Complete Block Design with three replications. Days to 50% flowering, plant height, number of effective tillers per hill, filled grain percentage, 1000 seed weight, number of spikelets per panicle, harvest index and yield per plant exhibited highly significant differences indicating the existence of genetic variability among the improved rice lines. There was not much variability in panicle length. Seed yield per plant was positively and significantly correlated with days to reach 50% flowering, plant height, the number of effective tillers per hill, filled grain percentage, number of spikelets per panicle and the harvest index at phenotypic and genotypic levels. This shows that indirect selection on these traits would be effective in improving grain yield. At the genotypic level, path coefficient analysis shows that number of spikelets per panicle, the 1000 grain weight, filled grain percentage, number of effective tillers per hill, plant height and harvest index has a positive influence on seed yield. The selection index based on the combination of number of effective tiller per hill, filled grain percentage, number of spikelets per panicle and seed yield per plant (ETPP+FGP+SPP+SYPP) has the highest genetic advance and relative efficiency. This indicated that indirect selection via these traits would be more efficient than direct selection using yield alone. Therefore, the genotypes; YAU- 1215-S-S-S-41-1-1, YAU-1211-9-3-1, YAU-1211-71-1-1, YAU-1211-118-2-1 and YAU-1201-151-1-1 could be selected based on multiple traits selection for further evaluation.