Combining Ability And Heterosis Studies In Rice (Oryza Sativa L.) Using Line X Tester Mating Design

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 4 testers) during kharif 2019 and 2020. Data was recorded on fourteen characters viz; days to 50% flowering, days to maturity, plant height, panicle length, spikeletes per panicle, grains per panicle, 1000 grain weight, biological yield per plant, harvest index, grain yield per plant, hulling percentage, L/B ratio, kernel length after cooking and gel consistency. Wide range of variation in mean performance of genotypes was observed for all the 14 characters under study. High heritability coupled with high genetic advance in per cent of mean were observed for the characters like grain yield per plant, grains per panicle, kernel length after cooking, harvest index, gel consistency, L/B ratio, spikeletes per panicle and biological yield per plant indicating that these characters are governed by additive gene action. Grain yield per plant possessed positive and highly significant correlation with harvest index, biological yield per plant, grains per panicle, hulling percentage, kernel length after cooking, panicle length, spikelets per panicle and 1000 grain weight at both phenotypic and genotypic 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 nonadditive gene actions. The significant and positive gca effects for grain yield per plant were exhibited by 8 lines viz;Vallabh basmati-21, Pusa basmati-1121, Pusa basmati-1, Pusa basmati-1509, Punjab basmati-5, Basmati CSR-30, Pusa basmati-1718 and Vallabh basmati-24 whereas, 2 tester i.e. Haryana basmati and Ngina-22 also showed positive and significant gca effects. These were found to be good general combiners for yield and other associate characters. Hence, these parents may be incorporated in breeding programme. Top 10 crosses namely, Basmati-564 x Taroari basmati, Basmati-386 x Haryana basmati, Punjab basmati-2 x Nagina- 22, Type-3 x Haryana basmati, Vallabh basmati-23 x Nagina-22, Pant basmati-1 x Punjab basmati-4, Pusa basmati-1718 x Nagina-22, Ranveer basmati x Haryana basmati, Pusa basamti-6 x Haryana basmati and Pant basmati-2 x Taroari basmati showed significant and positive sca effects for grain yield per plant. The five best crosses viz., Vallabh basmati-21 x Punjab basmati-4, Pusa basmati-1121 x Punjab basmati-4, Type-3 x Haryana basmati, Pusa basmati-1121 x Nagina-22 and Punjab basmati-2 x Nagina-22 exhibited positive and significant heterosis over better parent. While, the five best crosses viz., Pusa basmati-1121 x Nagina-22, Vallabh basmati-21 x Punjab basmati-4, Pusa basmati-1121 x Punjab basmati-4, Punjab basmati-2 x Nagina-22 and Basmati-386 x Haryana basmati exhibited positive and significant heterosis over the mid parent. Therefore, genetic yield potential could be enhanced by exploiting these crosses through heterosis breeding.