Genetic analysis of hybrid fertility and yield contributing traits in indica japonica and wide compatibility genotypes of rice Oryza sativa L

Abstract

The present investigation entitled Genetic analysis of hybrid fertility and yield contributing newlinetraits in indica, japonica and wide compatibility genotypes of rice (Oryza sativa L.) was newlineundertaken to get the information on nature and magnitude of gene action, combining ability newlineand heterosis and thereby indentifying potential parents and cross combinations for yield, cold newlinetolerance and disease restistance that could support further improvements of rice productivity newlineusing indica japonica hybrids. Eight parents viz; SKUA 500, SKUA 538, SKUA 536-2, HPR newline3106, HPR 2143, Bhrigudhan, Naggardhan and Varundhan were crossed following Griffing s newlinemethod 2, model I in a half diallel fashion. Experimental material comprising of eight rice newlineparents and twenty-eight hybrids were evaluated in RBD with three replications during kharif newline2021 and 2022 at Rice and Wheat Research Centre, Malan and for the cold tolerance in rabi newline2020-21at the experimental farm of the Department of Vegetable Science and Floriculture, newlineCSK HPKV, Palampur. Under cold conditions spikelet fertility was observed in the order of newlinejaponica x japonica lines gt japonica x wide compatible lines gt indica x japonica lines gt indica newlinex wide compatible lines gt indica x indica lines.The analysis of variance revealed significant newlinedifferences among the genotypes for all the traits studied in all the environments, suggesting newlineprevalence of wide range of genetic variability. Genotype x Environment (G × E) interaction newlinewas significant for most of the traits except days to 75% maturity, plant height, flag leaf newlinelength, flag leaf width, spikelet fertility, length:breadth ratio and amylose content indicating a newlinedefinite role of environment on the performance of genotypes. SCA variances were higher newlinethan the GCA Variances and average degree of dominance was more than unity, thus showing newlinepreponderance of non-additive gene action for all the traits except amylose content. Based on newlineGCA effects, SKUA 500, HPR 2143 and HPR 3106 were the most promising general newlinecombiners for g