E. Punitha and T. Sabesan
Abstract
The present study was carried out to assess the extent of divergence and evaluate the stem borer resistance in 120 rice genotypes under natural condition during Samba season. Mahala nobis D2 values and nonhierarchical Euclidean cluster analysis categorized the genotypes in eight clusters. The maximum intra cluster D2 was obtained in cluster VII (1973.205) and farthest inter cluster distance was observed between clusters IV and VII (4285.173). The clusters IV, VI and VII exerted that superior cluster mean performance. The characters viz., grain yield per plant, grain breadth and days to fifty per cent flowering were the major contributors towards genetic divergence. For stem borer resistance, data on dead heart symptoms and white ear symptom were observed under natural field conditions. Based on genetic diversity and screening for stem borer resistance studies, the genotypes AU1 GSR, ADT 44, ADT 47, BA-132, BA-147, GSR IR-2-11- R9-Y1-L2, Dayala modina, Thooyamalli and Kalanamak showed promising results. These genotypes could be exploited in the future crop breeding programme to develop resistant varieties against the rice yellow stem borer.