Screening of groundnut interspecific derivatives for resistance to Sclerotium rolfsii
Sclerotium rolfsii is a major constraint for production in most of the groundnut growing areas in India inflicting 28-30 per cent yield losses annually. Irrigated groundnut grown in the post-rainy and summer seasons in India is often infected by this pathogen. The 54 interspecific derivatives and 6 recombinant inbred lines (TAG-24 x R-9227 cross) along with 6 check varieties CDh-86, Dh-216, ICGV 91114, Dh-3-30, R-9227 and TAG-24) were screened for S. rolfsii resistance in sick plots during summer and Kharif2012 seasons. In summer 28 lines and 32 lines in Kharif showed highly resistant reaction to stem rot disease. High genetic variability and heritability was observed for disease and yield attributes viz., number of pods per plant, pod yield, harvest index, disease incidence at harvest, disease severity and disease spread irrespective of seasons. Per cent disease incidence at harvest was having strong significant negative association with dry pod yield per plant in both seasons. The interspecific derivatives viz., ICGV 3649-1, ICGV 4368-1, ICGV 3727-4, ICGV 34-1 and ICGV 4670-7 and recombinant inbred lines viz., RIL 3-14, RIL 6-1 and RIL 6-28 had desirable combination of high level of stem rot resistance and good agronomic attributes. These promising lines can been tested in trials over locations to confirm their superiority and utilized in breeding for Sclerotium disease resistance.