Morphological and molecular characterisation of Sclerotinia sclerotiorum (Lib.) de Bary isolates collected from multiple host crops using SSR markers

Sclerotinia sclerotiorum is a pathogen with broad host range and is known to cause severe losses. Majority of the studies focused on the losses caused by pathogen on Brassica sp. neglecting the fact that it also has a severe impact on horticultural crops. The objective of the study was to observe the morphological and molecular variability of the thirty isolates of Sclerotinia sclerotiorum collected from eighteen different hosts with major emphasis on horticultural crops. Morphological parameters such as colony colour, radial growth, colony texture, initiation of sclerotia formation, number of sclerotia formed, size of sclerotia, carpogenic germination, number of stipes formed, number of apothecial cups and diameter of apothecial cups were taken under consideration and the results showed that the isolates were morphologically different. Majority of the isolates showed white coloured colony and fluffy mycelial growth. Ten microsatellite markers were used to study the genetic variability, and no grouping of the isolates was observed in terms of regional distribution. All the isolates were grouped into two major clusters (A and B) having similarity index 0.23 and cluster B was further divided into three groups.