Generation Mean Analysis of Quantitative Traits in Restorer Lines of Rice (Oryza sativa L.)

Gene action and inheritance of quantitative traits associated with good out-pollination, agronomic and grain quality in restorer lines of rice was studied by generation mean analysis through six parameter model of Hayman. Eleven traits namely days to 50 per cent flowering, flag leaf area, plant height, number of panicles plant^-1, panicle length, number of filled grains panicle^-1, 100 seed weight, grain yield plant^-1, kernel length, kernel breadth and kernel length/breadth ratio were studied in five crosses viz., BCW 56 / C20 R, BCW 56 / 1005, C 20 R / DR 714-1-2R, C 20 R / 1005 and DR 714-1-2R / 1005. The A, B, C and D scales are significant and epistasis was noticed for all the characters in all the crosses except for plant height in cross BCW56/C20R, 100 seed weight in C20 R/DR 714-1-2 Rand kernel breadth in C 20 R / 1005. Grain yield plant-1recorded dominance variance in all the crosses. Hence, heterosis breeding can be exploited in all the crosses by crossing the parents with high yielding CMS sources for identifying heterotic combinations. Additive and non additive gene effects with duplicate type of epistasis was observed for yield and quality characters like plant height, number of panicles plant^-1, panicle length, number of filled grains panicle^-1, 100 seed weight, grain yield plant^-1, kernel length, kernel breadth and kernel L/B ratio in most of the crosses studied. Biparental mating, reciprocal recurrent selection and diallele selective mating systems could be exploited to obtain desirable recombinants having the characteristics of a restorer line with tallness, desirable flowering duration, reduced flag leaf area and more number of fertile spikelets. In crosses BCW 56 / C 20 R and BCW 56 / 1005 biparental mating followed by selection will be desirable to utilize both additive and non-additive gene action for number of filled grains panicle^-1 and grain yield plant^-1. The fixable gene effects namely additive (d) and additive x additive (i) gene effects were highly significant for the traits days to 50 per cent flowering in BCW 56 x C 20 R and C 20 R /DR 714-1-2Rand 100 seed weight in crosses BCW 56 /C 20 R and C 20 R/ 1005 and offer scope for improvement through phenotypic selection based on pedigree method in segregating generations by isolating desirable lines for the important floral, yield and quality traits for use as male parents in hybridization programmes.