Kalita, U.C.Pathak, Dalibha2020-11-062020-11-062019-07https://krishikosh.egranth.ac.in/handle/1/5810154609An experiment was conducted during the late sali season (August) of 2018 at Instruction cum Research Farm, Assam Agricultural University, Jorhat following 3 replicated RBD. The objective of the trail was to evaluate the performance of the genotypes under late sowing situation. Significant variation was observed for grain yield and its component characters. The mean sum of squares due to various sources of variation for 18 quantitative characters revealed the presence of significant differences for grain yield and its component characters. The estimates of phenotypic coefficient of variation (PCV) was found high for chaffs per panicle, grains per panicle, spikelet sterility %, spikelets per panicle, grain yield (kg/ha), tillers per hill, biological yield (kg/ha). The estimates of genotypic coefficient of variation (GCV) was found high for chaffs per panicle, grains per panicle, spikelet sterility %, spikelets per panicle, grain yield (kg/ha). Low estimates of GCV and PCV were recorded for the character viz., days to 50% flowering and days to maturity. In this study, a high heritability coupled with high genetic advance were observed for chaffs per panicle and grains per panicle indicating that the selection might be effective for bringing about improvement for these characters under delayed sown situation. Among the genotypes only one genotype viz., Gandhari was the top yielder (4170 kg/ha)because of its significantly lower number of days to both 50% flowering (101days) and days to maturing (131 ), spikelet sterility (23.13 %) than their corresponding values of the check Manoharsali; significantly higher spikelets per panicle (238.19), grains per panicle (183.07) grain yield (17.18 g/hill), straw weight (6575.16 kg/ha), biological yield (10745.10 kg/ha) and harvest index (38.86 %) than their corresponding values of the check Manoharsali and moderate performance for the remaining characters. The high GCV was observed for chaffs per panicle, grains per panicle, spikelets per panicle, spikelet sterility (%) and grain yield (kg/ha) and high PCV was observed for chaffs per panicle followed by grains per panicle, spikelet sterility (%), grain yield (kg/ha), tillers per hill, spikelets per panicle and biological yield (kg/ha).Grains per panicle, days to 50 per cent flowering, plant height (cm) , panicle length (cm), spikelets per panicle, chaffs per panicle, grain yield (kg/ha), grain yield (g/hill), spikelet sterility (%), 100-grain weight, days to maturity, biological yield (kg/ha), straw weight (kg/ha) and harvest index (%) had registered high heritability. A high heritability coupled with high genetic advance was observed for plant height (cm), spikelets per panicle, spikelet sterility (%), chaffs per panicle, grains per panicle, grain yield (kg/ha), grain yield (g/hill), biological yield (kg/ha), straw weight (kg/ha) and harvest index (%). Grain yield (kg/ha) exhibited significant positive correlation with plant height(cm), panicle length(cm), grains per panicle, spikelets per panicle, grain yield (g/hill) and straw weight (kg/ha). The significant negative correlation of grain yield (kg/ha) had observed with days to 50% flowering, spikelet sterility (%) and days to maturity. From the findings of this investigation, one genotype viz., Gandhari emerged as the outstanding genotype which could be directly used for cultivation in delayed sown situation. Some other promising genotypes that had average productivity more than 3500 kg/ha and yet significantly high yielder than the check Manoharsali under delayed sown condition were JR 29 , JR 16 , Basundhara and JR 60. These genotypes had shown their promise for recommendation under delayed sown condition provided the investigation is continued for another 2-3 years under the same conditionandcould be utilized as potential parental material in the hybridization programmes designed to develop suitable rice varieties for delayed sown situation.EnglishThesis