Yield and quality variants studies in Nagaland lines of Oryza sativa through principal component analysis and genetic divergence assessments

An experiment was conducted in the field to assess the existing variability in rice germplasm based on D² statistics for 29 quantitative traits. The whole germplasm was classified into 5 clusters, in which the highest inter-cluster distance was recorded between cluster III and cluster II. Cluster I showed the highest mean value for germination percentage, plant height, panicle weight, spikelet fertility, root length, total nitrogen, crude protein, grain N%, NutE, 100-grain weight, and grain yield per plant. It has been found that cluster II showed the highest mean value for days to 50% flowering, days to maturity, panicles per plant, stem dry weight, number of ear-bearing tillers, harvest index, chlorophyll a, and grain yield per plant and cluster III shown highest mean value for root dry weight, amylose content, PNUE, biological yield, and NHI. Cluster IV recorded the highest mean value for panicle length, chlorophyll B, and total chlorophyll, whereas cluster V recorded the highest mean value for flag leaf length, flag leaf breadth and flag leaf area. Principal component analysis revealed a total variability of 34.4% among genotypes contributed by PC₁ (18.2%) and PC₂ (16.2%). Chlorophyll a and total chlorophyll (7.41%) contributed maximum towards the observed diversity. Thupfu Lha and RCM from cluster I and Taposen Youli from cluster III have desirable characteristics, viz., grain N%, PNUE, NUtE, BY, and NHI and may be selected for intercrossing. Hence, simultaneous selection of these traits is advised for genetic improvement in the rice breeding program.