RAMESH BABU), PSREELAKSHMI, CH.2019-05-072019-05-072018http://krishikosh.egranth.ac.in/handle/1/5810102174D5722The present experiment entitled was carried out at Agricultural Research Station, Nellore, Andhra Pradesh from 2014 to 2016. Analysis of variance and high estimates of variability estimates for number of unfilled grains per panicle, test weight, grain yield per plant, water uptake, volume expansion ratio, gel consistancy and alkali spreading value indicating that these characters were under the influence of additive gene action and simple selection would be effective for the improvement of these characters. Combining ability analysis indicated the predominance of non-additive gene action for most of the traits. Significant heterosis for most of the traits in BPT 5204 x NLR 34449, RNR 2465 x NLR 145 suggested that genetic potential for yield improvement through pedigree method. For better quality improvement BPT 5204 x IR 36, RNR 2465 x IR 64 found to be good crosses. Association studies indicated that the number of ear bearing tillers per plant, number of filled grains per panicle, days to 50% flowering, harvest index and days to maturity exhibited positive significant association with grain yield, among quality traits, amylose content exhibited high positive significant association with head rice recovery and negative association with kernal L/B ratio. Generation mean analysis for seed yield and quality traits revealed that majority of the traits are under the influence of duplicate epistasis. In the selected crosses, inheritance studies on the rice blast resistance affirmed the dominance of resistance to susceptibility and the role of two gene interactions viz., duplicate (15:1) type of epistasis was observed for RNR 2465 x NLR 145, BPT 5204 x IR 64, RNR 2465 x IR 64 and BPT 5204 x NLR 34449. Two crosses viz., BPT 5204 x IR 36 and WGL 48684 x IR 36 exhibited 3:1 type of phenotypic ratio (R:S) indicated that the resistance is governed by single dominant gene.en-USnullThesis