Studies on Genetic Architecture for Yield and Its Contributing Traits in Rice (Oryza Sativa L.)

Abstract

coefficient analysis, combining ability and extent of heterosis for grain yield and its component traits using line × tester mating design (25 lines and 4 testers) during kharif 2018. Sixteen characters included in the study viz., days to 50% flowering, days to maturity, plant height (cm), flag leaf area (cm2), panicle bearing tillers per plant, panicle length (cm), spikelets/panicle, grains/panicle, spikelet fertility (%), 1000-grain weight (g), biological yield/plant (g), harvest-index (%), kernel length (mm), kernel breadth (mm), L:B ratio and grain yield/plant (g). Wide range of variation in mean performance of genotypes was observed for all the 16 characters under study. High heritability coupled with high genetic advance was observed for leaf area, spikelets/panicle, grains/panicle, L:B ratio and grain yield/plant, indicating that these characters are governed by additive gene action. Grain yield/plant showed highly significant and positive correlation with biological yield/ plant, harvest index, flag leaf area, panicle bearing tillers/plant, panicle length, 1000 grain weight, grains/panicle, spikelets/panicle and spikelets fertility at both levels. These characters either alone or in combination with yield could be utilized in rice breeding. Analysis of variance for combining ability revealed that gca variance among lines and testers were found highly significant for all metric traits. However, sca variance due to interaction between F1’s were found to be highly significant for all the characters under study. These findings indicated presence of both additive and non-additive gene actions. Five parents viz., NDRK 5062, NDRK 5025, NDRK 5063, NDRK 5081 and Vallabh Basmati 21 were found to be good general combiners for yield and other associate characters. Hence, these parents may be incorporated in breeding programme. The eight best crosses viz.,Pant 60 x IR 28, IR 64 x Vallabh Basmati 21, NDRK 5018 x IR 28, NDRK 5093 x Sugandha 5, NDRK 5037 x Sugandha 5, NDRK 5059 x Pusa Basmati 1509, NDRK 5081 x Pusa Basmati 1509 and IR 64 x IR 28 showed significant and positive sca effects for grain yield. The five best crosses viz., NDRK 5081x Pusa Basmati 1509, Sarjoo 52 x Pusa Basmati 1509, Pant 60 x IR 28, NDRK 5040 x Pusa Basmati 1509 and IR 64 x Vallabh Basmati 21 exhibiting positive and significant heterosis over better parent. While, the five best crosses viz.,NDRK 5081 x Vallabh Basmati 21, NDRK 5062 x Vallabh Basmati 21, NDRK 5025 x Vallabh Basmati 21, NDRK 5040 x Vallabh Basmati 21 and NDRK 5063 x Vallabh Basmati exhibited positive and significant heterosis over the standard variety. Therefore, genetic yield potential could be enhanced by exploiting these crosses through heterosis breeding.