S.K.PrashanthiMadhu.S.Giri2016-11-022016-11-022009http://krishikosh.egranth.ac.in/handle/1/83514Pomegranate (Punica granatum L.) is an important fruit crop of India and other subtropical countries. Bacterial blight caused by Xanthomonas axonopodis pv. punicae (Hingorani and Singh, 1959) Vauterin et al. is a major threat to pomegranate production. Morphological, physiological, biochemical and molecular diversity of the 16 isolates of Xanthomonas axonopodis pv. punicae collected from various parts of Karnataka was studied. Lokapur and Ramatala isolates produced highly mucoid colonies on YDCA and GYCA medium. The maximum colony size was found in case of Lokapur, Ramatala, Gulaganjikoppa and Kothabala isolates, while the least colony diameter was recorded in Uthnal isolate. YDCA, GYCA and YNA media supported good growth of all the isolates. Many isolates failed to grow on the XPS medium. The temperature 200C supported the maximum growth of 11 isolates, while 300C was found optimum for the remaining five isolates. All the isolates showed maximum growth at pH 5.0. However, Ramatala and Mudhol isolates showed good growth even at pH 8.0. Among sixteen isolates, only five isolates could hydrolyse starch and they showed variation in their ability to hydrolyse starch. Almost all the isolates produced strong to weak acids from sucrose, maltose and dextrose, where as Hagaribommanahally isolate failed to produce acid from sucrose and maltose. Bardol isolate failed to produce acid from sucrose. Uthnal, Bardol and Bandi isolates failed to produce hydrogen sulphide gas where as remaining isolates produced heavy to weak H2S gas. RAPD analysis distinguished the 16 isolates in to 2 major clusters; cluster A was represented by a single isolate i.e., Hagaribommanahally isolate of Bellary district and cluster B encompassed all other isolates. The maximum genetic similarity of 91% was observed between Gulaganjikoppa and Kurubararamanahally isolate; least similarity was found between Thavargere and Shravanagere isolates. Molecular diversity study indicated the fact that, the variation is independent of geographical location.Thesis