Multivariate Analysis in Tropical Japonica “New Plant Type” Rice (Oryza sativa L.)

Genetic diversity among fifty two “new plant type” lines including four improved cultivars was studied using Mahalanobis D² statistic under shallow lowland ecosystem. The genotypes were grouped into 10 clusters showing fair degree of relationship between geographic distribution and genetic divergence. Cluster I with 33 genotypes was the largest, while cluster III, IV, V, VII, VIII, IX, X were monogenotypic. Genotypes in cluster VI had highest intra-cluster divergence followed by cluster II and I while highest inter-cluster divergence was between cluster VI and IX followed by VII and X. Maturity duration contributed the maximum to the total divergence. Other traits with appreciable contribution to total divergence were spikelets per panicle, grain filling (%), panicle number/m², panicle length (cm) and harvest index (%). All the minimum and maximum cluster mean values were distributed in relatively distant clusters. The member of the clusters VII, X, VI and I may be further evaluated as these clusters were observed to possess high cluster mean for grain yield. Further, it is suggested that cross combination of IR73964-120-5-3-2 x IR72164-110-1-2, IR73964-120-5-3-2 x IR72967-12-2-3, Naveen x IR71701-28-1-4-3, IR75268-45-2-5-3 x IR71676-106-10-3, Naveen x IR72967-12-2-3, IR73964-120-5-3-2 x IR71701-28-1-1 showing high D² matrix value are expected to produce superior progenies.