RESISTANCE IN GROUNDNUT TO SCLEROTIUM ROLFSII-CAUSED STEM AND POD ROT

Eight hundred and fifty-nine groundnut germplasm accessions and breeding lines were screened in field trials for resistance to stem and pod rot caused by Sclerotium rolfsii during the 1985-88 post-rainy seasons at the ICRISAT Asia Center, Patancheru, India. Lines that showed low susceptibility to stem and pod rot (< 10%) were further evaluated at the Marathwada Agricultural University farm, Parbhani, India, during 1987-91 in the rainy and summer seasons. Of the 20 selected genotypes seven interspecific hybrid derivatives (326, 988, 1019, 1024, 1065, 1267, and 1364) consistently exhibited stable resistance to both stem and pod rot. Nine breeding lines (ICGV 86034, 86124, 86252, 86388, 86590, 86606, 86635, 87160, and 87359) showed low susceptibility to stem and/or pod rot. Effective screening for stem and pod rot resistance was possible in the post-rainy and summer seasons. Several lines with low susceptibility to S. rolfsii also possess resistance to rust (Puccinia arachidis) and moderate resistance/tolerance to late leaf spot (Phaeoisariopsis personata). Useful features of these lines are discussed.