Abstract

Sclerotinia stem rot caused by Sclerotinia sclerotiorum (Lib.) de Bary is one of the most serious disease and causes damage to oilseed Brassica. Seventeen geographical isolates of S. sclerotiorum from different geographical locations of India were compared for their growth under artificial culture conditions and the result was validated throughrandom amplified polymorphic DNA (RAPD) markers. Based on the morphological studies, the isolates were grouped into fast growing (SR-01, SR-02, SR-05, SR-16) and intermediate (SR-03, SR-04, SR-07, SR-10 to SR-13, SR-18), though the rest of the isolates showed comparatively a slow mycelial growth rate. In RAPD analysis for their genetic diversity, fifty decamer primers of arbitrary sequences produced 692 scorable amplicons ranging from 180 to 3900 bp in size. Out of these, 385 fractionated fragments were reported polymorphic. As an average, 13-14 unambiguous and reproducible amplified products were generated by single primer (minimum of 4 and maximum of 23 fragments). Hence, the present investigation confirmed the diversity among the different geographical isolates from India.

Key words: Brassica, Sclerotinia sclerotiorum, morphological variability, random amplified polymorphic DNA (RAPD).