Genetic analysis of reciprocal differences for yield and yield attributing traits in segregating populations of rice (Oryza sativa L.)

Reciprocal differences prevail in nature mainly due to unequal contribution of cytoplasmic determinants from male and female gametes to the zygote, but the influence of female parent often extends beyond simple genetic transmission. In this report, we estimate the cytoplasmic and maternal effects in rice and their adequacy in describing the observed reciprocal differences based on study of the parents, F2s, F3s and reciprocal cross progenies. Our study revealed that significant differences were observed for majority of yield & yield attributing traits between mean performance of straight & reciprocal F2 & F3 populations derived by crossing BPT-5204 & HPR-14 indicating the presence of reciprocal differences. High PCV, GCV coupled with high heritability & GAM observed for number of tillers, number of productive tillers, biomass & harvest index. High heritability & high GAM was observed for plant height in straight & reciprocal F2 & F3 populations. The variability by Shapiro-Wilk ‘W’ normality test revealed normal distribution for total grains, fertile grains per panicle & grain weight per panicle in F2 population, whereas number of productive tillers, flag leaf length, total grains per panicles, fertile grains per panicle, grain weight per panicle, test weight, harvest index & grain length in both straight and reciprocal F3 population. Multi trait selection index was performed to evaluate F3 families for quantitative traits & selected top 20 F3 families in both straight & reciprocal crosses. Best F3 families showed grain yield of 41% to 52% gain over the better parent BPT-5204 in straight & 37% to 61% gain in reciprocal crosses indicating the effect of cytoplasmic differences among the parents in the derived crosses. Further, these top performing superior F3 families can be utilized for developing breeding lines for improvement of the traits.