Somasekhara, Y. MMALAPPA, S. KOHALLI2017-09-142017-09-142016-07-25Th-11400http://krishikosh.egranth.ac.in/handle/1/5810031167Powdery mildew disease caused by Erysiphe polygoni DC. is a major constraint in the black gram cultivation, causing both quantitative and qualitative losses (40-90%). Development of resistant cultivars plays an important role in management of powdery mildew. An attempt was made to identify resistant sources of black gram genotypes against powdery mildew. Of 188 genotypes screened under field (rabi & kharif) and glass house conditions, the lowest disease severity was observed in resistant genotypes viz., LBG-17 (7.64 & 7.5%), IC-281977 (5.5 & 5.8%) and RASHMI (5.0 & 5.2%) under field conditions during kharif and glass house conditions respectively. Two resistant genotypes viz., LBG- 17 and RASHMI showed disease severity of 5.80% during rabi. The disease severity of moderately resistant genotypes viz., LBG-626 (20.9, 18.1 & 20.5%), KU-5-527 (17.9, 16.8 & 18.8%) and IC-546468 (17.5, 19.1 & 19.0%) under field (rabi & kharif) and glass house conditions respectively. The amount of phenols, peroxidase, polyphenyl oxidase, chitinase and phenylammonia lyase content in infected leaves of resistant genotypes viz., LBG-17, IC-281977 and RASHMI was 7.21, 7.62, 7.63 mg/g LFW; 6.34, 4.71, 5.37 mg/g LFW; 5.12, 4.67, 4.92 mg/g LFW; 152.0, 166.0, 176.0 mMol/g LFW and 2.51, 2.43, 2.01 mg/g LFW respectively was more compared to the infected leaves of susceptible genotypes. Accumulation of total sugar less in infected leaves of resistant genotypes ranged from 155- 162 μg/g LFW compared to susceptible resistant genotypes (295-300 μg/g LFW). The resistant genotypes would be used for further breeding programmes to develop resistant black gram varieties against powdery mildew.ennullThesis