GENETIC ANALYSIS AND HYBRID VIGOR STUDY OF GRAIN YIELD AND OTHER QUANTITATIVE TRAITS IN AUTOTETRAPLOID RICE

Abstract

Genetic analysis and genotype-by-environment interaction for important traits of autotetraploid rice were evaluated by additive, dominance and additive × additive model. It was shown that genetic effects had more influence on grain yield and other quantitative traits of autotetraploid rice than genotypic environment interaction. Plant height, panicle length, seed set, grain yield, dry matter production and 1000-grain weight were mainly regulated by dominance variance. Additive and additive × additive gene action constructed the main proportion of genetic variance for heading date (flowering), number of panicles, grains per panicle, grain length, however grain width was supposed to be affected by additive × additive and dominance variance. Flag leaf length and width, fresh weight, peduncle length, unfilled grains and awn length were greatly influenced by genotypic environment interaction. Heading date produced highly negative heterosis over mid parent (Hpm) and better parent (Hpb), whereas Hpm and Hpb were detected to be highly positive and significant for grain yield, seed set, peduncle length, filled grains and 1000-grain weight in F1 and F2 generations. The results indicated that autotetraploid hybrids 96025 × Jackson (indica/japonica), 96025 × Linglun (indica/indica) and Linglun × Jackson (indica/japonica) showed highly significant hybrid vigor with improved seed set percentage and grain yield. These results suggest that intraspecific autotetraploid rice hybrids have more hybrid vigor as compared to intra-subspecific autotetraploid rice hybrids and autotetraploid rice has the potential to be used for further studies and commercial application.