Genetic Analysis of Yield and Its Related Traits in Rice (Oryza Sativa L.)

Abstract

An experiment was conducted to find out variance, genetic parameters, correlation and path coefficient analysis, combining ability and extent of heterosis for grain yield and its component traits using line x tester mating design (20 lines and 5 testers) during kharif 2018. Fifteen characters included in the study are days to 50% flowering, plant height (cm), flag leaf area (cm2), panicle bearing tillers per plant, panicle length (cm), spikelets per panicle, grains per panicle, spikelet fertility (%), 1000-grain weight (g), biological yield per plant (g), harvest-index (%), kernel length (mm), kernel breadth (mm), L:B ratio and grain yield per plant (g). Wide range of variation in mean performance of genotypes was observed for all the 15 characters under study. High heritability coupled with high genetic advance in per cent of mean were observed for the characters like grains per panicle, spikelets per panicle, and L:B ratio, indicating that these characters are governed by additive gene action. Grain yield per plant showed highly significant and positive correlation with 1000 grain weight, biological yield per plant, harvest index, kernel length, panicle bearing tillers per plant, L/B ratio, panicle length, flag leaf area, spikelets per panicle, grains per 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 was found to be highly significant for all the characters under study. These findings indicated presence of both additive and non-additive gene actions. The significant and positive gca effects for grain yield per plant were exhibited by 6 lines and 2 testers which viz., NDR 359, IR 28, IR 66, IR 85897, Asha and Gaur 1, among lines, Pusa Basmati 1509 and Pusa Basmati 1 teste were found to be good general combiners for yield and other associate characters. Hence, these parents may be incorporated in breeding programme. The ten best crosses viz., IR 66 x PB 1, Harsha x MTU 1010, Karthika x PB 1509, IR 28 x MTU 1010, Gaur 1 x PB 1509, Aruna x PB 1, Asha x PB 1509, Co 10 x PB 1121, IR 29 x PB 1121 and PUSA 44 x PB 1 showed significant and positive sca effects for grain yield. The five best crosses viz., GAUR 1 x PB 1509, Gaur 1 x MTU 1010, Asha x PB 1509, IR28 x MTU 1010 and Karthika x PB 1509, exhibited positive and significant heterosis over better parent. While, the five best crosses viz., IR 28 x MTU 1010, Harsha x MTU 1010, Co 10 x PB 1121, Pusa 44 x MTU 1010 and GR 104 x PB 1121 exhibited positive and significant heterosis over the standard variety. Therefore, genetic yield potential could be enhanced by exploiting these crosses through heterosis breeding.