Mahalanobis's D2 and canonical analyses have been used to assess the nature of divergence and its relationship with the components of genetic variation in rice for four characters, namely height of the plant, number of productive tillers, duration of variety and ear-length, related to yield and fitness. They were found to be potent enough to distinctly discriminate the indica and japonica races, early, medium and late maturity groups and the varieties of China, Japan and Taiwan and hilly and plain varieties of India which indicated that genetic diversity might be related with geographic diversity in rice. The probable causes responsible for retention of variability in rice crop have also been explored. The nature of evolutionary pattern has been traced out indicating the most important role of flowering time in the major axis of differentiation. A brief scheme of the indica X japonica hybridization programme based on genetic divergence for the maximum exploitation of heterotic effect has also been put forth.
