Genetic Divergence in Indigenous Wild and Cultivated Rice Species of Manipur Valley

Genetic divergence of 32 indigenous rice germplasms and five wild rice of which three from Manipur and two wild rice procured from IRRI, Philippines was investigated using Mahalanobis, statistic. Based on twelve agromorphological characters, the thirty-seven germplasms both wild and cultivated were grouped into five clusters based on the relative magnitudes of values following Tocher's method of cluster formation. Based on the rank totals, the characters which contributed maximum towards genetic divergence in the present studies were grain yield/plant, spikelet/panicle, 100 grain weight, grain length, days to 50% flowering, ear bearing tillers/plant, and flag leaf length. In the present study, maximum intercluster distance was estimated between cluster III and ( ) which was closed followed by clusters II and V ( ). On the basis of their greater intercluster distance, high value of cluster mean according to the character to be improved and performance of the individual germplasms for the character, the germplasms could be used in hybridization programme for improvement of different plant characters in the rice germplasms of Manipur. 1. Introduction Manipur valley which is also considered as rice bowl of the state has a large variability of indigenous rice cultivars that belong to Asian cultivated rice O. sativa L. subspecies indica. So far, 44 indigenous rice cultivars along with two wild rice wainuchara one with perennial form and murshi another with annual weedy form have been recorded from Manipur valley by Singh and Sharma [1]. If one considers the percentage availability of indigenous rice cultivar per unit area Manipur valley has one land race of rice per 42？sq·km. According to traditional classification, more than 50 rice cultivars were cultivated in Manipur valley before the introduction of high-yielding varieties bred in Manipur. The high-yielding varieties of rice introduced from the plain or hill regions of the northern and southern parts of the country do not perform well in northeastern hill region [2]. The importance of local land races of rice in breeding programme lies in the evolution of gene complexes in the local cultivars that have coadapted to specific local environment through long period of natural selection. These gene complexes may not be readily reconstituted even by the modern recombinant DNA technology; we have to utilize the naturally occurring gene complexes for breeding of rice for specific local conditions. The basic importance of genetic diversity in breeding for high yield has long been recognized as is evident from the