Molecular diagnosis to identify new sources of resistance to sclerotinia blight in groundnut (Arachis hypogaea L.)

Sclerotinia blight, caused by soil-borne fungus Sclerotinia minor Jagger, is one of the destructive diseases in groundnut. Pathogen affected plants usually displays lesions, wilt and collapse which cause high yield losses. Traditional field screening is time and resources consuming. Molecular markers associated with resistance genes offer an alternative selection technique which is relatively easy, more definite and not influenced by environmental fluctuations. In the present investigation, a marker-assisted diagnosis was done to screen 256 diverse germplasm for the presence or absence of SSR markers reported resistance or susceptibility to sclerotinia blight. One hundred and forty two genotypes from different botanical varieties were recognized as new potential sources of resistance to sclerotinia blight for field evaluation. The banding pattern related to the disease resistance is observed at high frequency in the variety vulgaris (39.4 %) and less distributed in the varieties fastigiata (38.0 %) and hypogaea (19.7 %) among the resistant genotypes in the collection. These genotypes had same banding pattern as reported for resistance germplasm. This work reports the successful application of marker-assisted diagnosis as a tool to identify resistance to sclerotinia blight in diverse collections.