Genetic diversity of New Plant Type rice selections in relation to indica, tropical japonicas, temperate japonicas and irrigated cultures

New Plant Type (NPT) breeding is one of the potential approaches for raising yield ceiling in irrigated rice. Fourty two promising NPT selections along with 6 indica, 4 tropical japonica, 3 temperate japonica and 3 irrigated cultures were studied for the possibility of further exploitation of these lines for breaking yield ceiling. The analysis of variance revealed sufficient variation among the genotypes for all the ten quantitative characters, whereas significant G x E were observed for all the characters except panicle length, flag leaf length and width. High phenotypic (PCV), genotypic (GCV) coefficient of variation and high heritability along with high expected genetic advance were recorded for panicle length, flag leaf length, fertile grains panicle-1 , total no. of spikelet, 100 grain wt. and grain yield. Grain yield had positive association for most of the characters except test weight. Higher and positive direct effect on grain yield was exerted by panicle length, no. of fertile grains/panicle and no. of tillers/hill. The D2 analysis revealed that genotypes exhibited considerable diversity and were grouped in to eight clusters. The clustering pattern indicated that the NPT selections had clustered differently in comparison to the tropical japonicas and temperate japonicas. Canonical analysis with PCA further clarified that most of the NPT selections had sufficient diversity with respect to tropical japonicas, temperate japonicas, derivatives of indica/ temperate japonicas and even specific popular indica varieties. Therefore, NPTs could be potentially exploited for recombination breeding with these genotypes.