Studies on genetic components for yield and blast resistance in aromatic rice

Abstract

newline The present investigation entitled Studies on genetic components for yield and blast resistance in aromatic rice (Oryza sativa L.) was carried out at Rice and Wheat Research Centre, Malan, Himachal Pradesh. In the experiment involving fifty aromatic and basmati rice germplasm, analysis of variance revealed sufficient genetic variability for all eighteen traits. Based on mean performance the highest grain yield/plant was observed in HPR 2694 followed by Katali, HPR 2750, Jammu Basmati and Pusa 1637. The estimates of GCV, PCV, heritability and genetic advance were high for maturity period, spikelets/panicle, grains/panicles, biological yield/plant and harvest index. Grain yield/plant had significant positive correlation with spikelets/panicle, grains/panicle and harvest index at both phenotypic and genotypic level. Harvest index had the highest positive direct effects followed by biological yield/plant, spikelets/panicle, spikelet fertility and grain length at both phenotypic and genotypic level. Total genotypes were grouped into ten clusters by using Ward s method. Highest intracluster distance observed in cluster V while highest inter-cluster distance was found between cluster VIII and V. newlineNine parents and their crosses were evaluated in half diallel fashion using Griffing s numerical approach during Kharif 2018. ANOVA revealed that both additive and non-additive gene action were involved in the inheritance of all traits. The preponderance of additive gene action was observed in the inheritance of ten traits viz., days to 75% maturity, plant height, spikelets/panicle, grains/panicle, harvest index, grain length, grain breadth, L/B ratio, amylose content and grain yield/plant. Preponderance of non-additive gene action was observed in the inheritance of eight traits viz., days to 50% flowering, maturity period, total tillers/plant, effective tillers/plant, panicle length, spikelet fertility, biological yield/plant and test weight. HPR 3007 followed by HPR 1156 and Kasturi were the superior parents based on high grain yield/plant and general combining ability. Cross HPR 3007 × HPR 2373 was the best followed by HPR 3007 × HPR 2612, Kasturi × HPR 2612 and HPR 3007 × HPR 3010 based on high grain yield/plant, heterosis and specific combining ability. All parents and crosses were resistant to leaf and neck blast except parents HPR 2373, HPR 2612, Pusa Basmati 1121 and crosses Pusa Basmati 1121 × HPR 2373, Pusa Basmati 1121 × HPR 2612 and HPR 2373 × HPR 2612. newlineNine parents of half diallel and their F1 and F2 were evaluated against Pyricularia oryzae isolates Po-HPU2216-5 for leaf and neck under artificial epiphytotic conditions at RWRC Malan. Based on disease reaction of F1 and F2 populations in resistant × susceptible and resistant × resistant crosses, it was observed that resistance in genotypes HPR 2880, HPR 3001, HPR 3007 and Kasturi was governed by two independently inherited dominant resistance genes whereas, three resistance genes conferred resistance in genotypes HPR 1156 and HPR 3010 for both leaf and neck blast. Segregation pattern in F2 populations in resistant × resistant crosses suggested that resistance genes for leaf and neck blast have at least one common allele in genotypes HPR 2880, HPR 3001, HPR 3007 and Kasturi which are different from the genes identified in genotypes HPR 1156 and HPR 3010. newline