Kumar, RajeshNARAYAN, KUMAR MRINMAY2023-04-262023-04-262021M/PBG/156/2019-20https://krishikosh.egranth.ac.in/handle/1/5810196725The present research programme entitled “Genetic evaluation of rice (Oryza sativa L.) genotypes under upland condition”, consisting of fifteen genotypes, was conducted at BSP (Breeder Seed Production) Plot No.-16, Tirhut college of Agriculture, Dholi, Muzaffarpur during Kharif season 2020. The objective of the investigation was to assess the variability for yield and yield attributing traits to work out trait association of yield parameters and to assess genetic divergence among rice genotypes. Utilizing mean values of ten quantitative traits, the analysis was conducted for estimating several genetic parameters such as variability, heritability, and genetic advances, correlation among the different traits, direct and indirect effects on grain yield, and genetic divergence. Considering the per se performance at 5% level of significance, genotypes HL-18-WS-20-2, HL-18-WS-20-3 and HL-18-WS-20-10 outyielded the local check MTU-1010. Genotypes HL-18-WS-20-10, HL-18-WS-23-29 and HL-18-WS-39-24-8 were earlier than the best check variety MTU-1010 indicating that these three genotypes have the potential to be used for development of early maturity or short duration rice varieties. For all the traits, variance analysis revealed fairly substantial differences between genotypes. The discrepancies between the GCV and PCV for all the traits were found to be minimal, indicating that the environment had a minor impact on their expression. “Plant height, no. of panicles per plant, spikelet fertility, L/B ratio, test weight, and yield per plot” had high heritability and high to moderate genetic advance as percent of mean, implying that a simple selection scheme for these traits would be successful in achieving genetic improvement in the desired direction. “No. of tillers per plant, no. of panicles per plant, spikelet fertility, L/B ratio and test weight” showed strong and positive association with grain yield, as a result these characters may be given priority in the selection procedure for yield improvement. No. of tillers per plant showed a positive significant association with spikelet fertility and L/B ratio. The L/B ratio and test weight had significant positive correlation with spikelet fertility. The L/B ratio had a significant positive relationship with test weight. Plant height showed a significant negative correlation with the number of panicles per plant whereas number of panicles per plant, spikelet fertility, and L/B ratio all had a negative significant correlation with panicle length.” The path coefficient analysis was conducted to bifurcate the phenotypic correlation coefficient into measures of direct and indirect effect. The findings of phenotypic path coefficient study showed that the traits like no. of panicles per plant, spikelet fertility and test weight are major determinants of grain yield per plot as they showed high to moderate direct positive effect (0.447, 0.314 and 0.227) on grain yield per plot per se. Diversity study was carried out using Mahalanobis’s D2 analysis, and the clustering of genotypes was done using Rao’s Tocher method. All the fifteen genotypes were divided into six overlapping clusters. Cluster I had the maximum five genotypes followed by cluster having four genotypes. The traits “plant height, L/B ratio, test weight, days to maturity, and spikelet fertility” were the major contribution towards total diversity. The inter cluster distances were greater than the intra-cluster distances suggesting the genotypes grouped in different clusters were diverse than those included within same cluster. Cluster IV and VI had the maximum inter cluster distance indicating that the genotype in these clusters can be exploited for their heterotic potential.EnglishThesis