Cultural and morphological variability among the isolates of Sclerotium rolfsii causing stem rot in groundnut

Abstract

Groundnut (Arachis hypogaea L.) is an important oil seed crop in the world belonging to the Leguminosae family. Cultural and morphological variability among thirty isolates of Sclerotium rolfsii were studied based on their growth rate, colony colour, mycelial appearance and sclerotial formation, colour, size, shape of sclerotia, test weight and number of sclerotia per plate, sclerotial arrangement and maturity days of sclerotia on PDA. Significant variability with respect to mycelial and sclerotial characters across isolates of S. rolfsii, obtained from different locations of North eastern Karnataka. Mycelial compatibility among the isolates was also assessed, out of 435 combinations of 30 isolates, 155 combinations were compatible reaction (35.63% of all the combinations) whereas the remaining 280 combinations were incompatible (64.36% of all combinations). Based on mycelial incompatibility, 21 vegetative compatible groups (VCG) were identified among the isolates.