Mahalanobis’s D2 statistics of some deep-water rice cultivars of Dhemaji district, Assam for genetic divergence analysis.

A study has been conducted to assess the genetic divergence of ten widely cultivated indigenous deep-water rice cultivars (viz. Panikakuwa, Kakuwa, Miabao, Dalbao, Maguribao, Negheribao, Panidhan, Bhubao, Amana and Happybao), collected from different paddy growing fields of Dhemaji district, Assam. The nature and the magnitude of genetic divergence has been estimated using Mahalanobis’s D2-statistics. Highest genetic divergence has been shown by the cultivar Negheribao, Dalbao. and Miabao (8.09452, 7.93156 and 7.92378 respectively). Five yield attributing characters viz. length of the panicle, 1000 seeds weight, number of spikelet per panicle, panicle per plant, percentage of seed setting were studied for percentage contribution and correlation coefficient towards yield. Dalbao has also been found to possess several characters of ideal panicle type. Dalbao and Negheribao having superior panicle traits may be considered for inclusion in deep- water rice breeding programmes. These cultivars might be included in further hybridization programme. Highest contributing characters to grain yield were number of spikelet per panicle (66.6%) and panicle per plant (58.1%). These characters could be used as selection indices in yield improvement. The cultivar Dalbao shows both panicle traits of rice ideal panicle type and has also shows a good range of genetic divergence among all. Thus this cultivar shows extreme promises and hence should be considered for inclusion for deep-water rice breeding programmes and also for consumption.