Existing Status and Genetic Divergence of Agro-Morphological Characters in Bangladeshi Fine Rice

摘要

A set of 30 rice (Oryza sativa L.) cultivars including 28 primitives, one exotic and one improved variety were collected from different agro-ecological zones of Bangladesh. The experiment was conducted in a randomized complete block design with threereplications during the wet season (July-December) of 2009 at the Plant Breeding Field Laboratory, Hajee Mohammad Danesh Science and Technology University, Dinajpur. The existing status regarding cultivation and preservation attitude were realized through an oral interview with 20 randomly selected farmers of each location from where a particular cultivar was collected. Four cultivars ('Kalozira', 'Badshabhog', 'Zethakatari', 'Katari') were most preferred by innovative farmers due to their use as food and in different traditional and religious festivals. Cultivars such as 'Shilkamal', 'Binnipakri', 'Darkashail', 'Dudshar', 'Lalchikon' and 'Uknimodhu' were rarely cultivated, hence the need to preserve them. The 30 cultivars were grouped into 7 clustersthrough principal component analysis and D2 statistics based on 12 agro-morphological characters. Cluster VI comprising 'BR34' and 'Darkashail' produced the highest yield (4.05 t/ha). Days to maturity was generally high in all 7 clusters and ranged from112.7-132.3 days; no cultivars matured slowly. Therefore, the development of rapidly maturing varieties by conventional breeding is assumed to be very difficult in fine rice. Among the 12 characters, spikelets/panicle exerted maximum weighting (20.37%) on total genetic divergence while percentage sterility had the least weighting (3.58%). Since highest intercluster distance (651.88) was observed between clusters III ('Malshira', 'Chiconsarna', 'Lalchicon', 'Radhunipagal', 'NazirshaiP, 'Lalfota', 'Sumonsarna') and VI ('BR34', 'Darkashail'), parents could be selected from these two clusters to obtain desirable segregants in the F_2 generation. Alternatively, one parent from each cluster could be selected to initiate a diallel cross to assess the best cross combination and to identify those parents with high general combining ability for improvement.