Genetic Divergence Studies for Gall Midge Incidence, Earliness, Yield and Yield Components in Rice (Oryza sativa L.) Genotypes in Telangana State

Abstract

The study was carried out with 32 genotypes of rice (Oryza sativa L.) under irrigated system in RBD design with three replications at Agricultural Research Station, Kunaram in Telangana State during the rainy season of 2017. In general, major problem is high incidence of gall midge (Biotype 3) in rainy season under early as well as late planting conditions in Northern Zone of Telangana State. Hence, all the 32 genotypes were evaluated with an aim to know the divergence among them for gall midge incidence, earliness, yield and yield components. Based on D2 analysis, 32 genotypes were distributed into twelve clusters with the cluster I (12) containing maximum number of genotypes followed by cluster II (9). Highest inter cluster distances were observed between the clusters X and XII (2469.5) followed by III and XII (2283.3), and VII and XII (2173.6) suggesting wide diversity between the traits. Cluster mean analysis revealed that genotype, WGL 1119 from the cluster V would be used in breeding programme to develop gall midge resistant, high yielding, early duration, non lodging, medium slender grain genotypes as it recorded very low incidence of galls (0.9%) with high yield (4869.7 kg/ha), early duration (84.7 days), short stature (93.7 cm) and less 1000-grain weight (14.8 g). The genotypes, KNM 2305 and MTU 1001 from the clusters viz., VIII and X, respectively were identified as potential lines for developing high yielding, early and medium duration, long bold or long slender grain varieties. Among the traits studied, days to 50% flowering (55.8%) and 1000-grain weight (31.9%) manifested highest contribution towards total divergence, thus, these traits could be given due importance by the breeders for development of superior rice genotypes under crop improvement programme.