I. K. KalappanavarArunakumar G. S.2016-07-262016-07-262013http://krishikosh.egranth.ac.in/handle/1/69866Off-season survey in Chikmagalur and Chitradurga districts of Karnataka revealed the absence of wheat crop. Three years normal season survey indicated the presence 20 different pathotypes. The pathotype 121R63-1 (77-5) was dominant and molecular profiling of 25 different isolates showed high genetic variability. UAS-326, UAS-315, VL-616, VL-924, HD-2189, HD-2932, HD-3091, NI-5439, HI- 977, HS-420, DBW-16, KRL-210, Pavon-76, RL-6077 and Parula were identified as slow leaf rusters and Agra Local, Lal Bahadur, Lok-1, Sonalika, C-306, DWR-162, PBW-343, DBW-17 and HS-240 were identified as fast leaf rusters. Molecular characterization of bread wheat showed 12 genotypes with Lr34/Yr18/Pm38, seven genotypes with Lr46/Yr29/Pm39 and none of the genotypes showed Lr67/Yr46. However, five genotypes (HD-2189, UAS- 315, VL-616, NW-4091 and RAJ-4270) carryed both Lr34/Yr18/Pm38 and Lr46/Yr29/Pm39 genes. Isozymes study revealed a higher variation of peroxidase and polyphenol oxidase at different growth stages under inoculated and uninoculated conditions. Pre-penetration processes of uredospore were not a good criterion for selection of slow leaf rusters. Loss of total grain protein content (GPC) was either increased or decreased or no significant changes observed when compared with protected and unprotected conditions among all the three group of genotypes. No significant difference was observed in the mean damaged starch of slow leaf rusters, whereas susceptible genotypes showed significant differences. Wet gluten and dry gluten content (%) was affected by leaf rust. Slow leaf ruster genotypes showed an average highest content of three micro-nutrients, viz zinc, iron and copper. The average yield loss was minimum in resistant and slow leaf rusters. However, it was very high in susceptible genotypes. A combi- product (Pyraclostrobin 13.3% + Epoxiconazole 5%) @ 0.1 % was found to be the best alternative to the propiconazole.Thesis