Biodiversity among the isolates of Sclerotium rolfsii of chickpea in Pakistan

Twelve isolates of Sclerotium rolfsii Sacc. were obtained from different locations in Pakistan to study variation among them. On the basis of morphological characters, three isolates (AT-1, AT-2, RW-2) were fast growing (84.6 to 90.0 mm), three (SR-1, CH-1, DL-2) intermediate (50.2 to 76.7 mm) and others exhibited slow radial colony growth (16.0 to 40.8 mm). The isolates CH-1 and RW-1 ranked as high producer of (547 sclerotia whereas SRL-1, CH-2, DL-1 and RW-2 were intermediate (423 to 444 sclerotia) and the others showed the least number of sclerotia) formation (260 to 386 sclerotia). The isolates RW-2, AT-3 and SR-1 produced bigger size of sclerotia (48.5 to 57.8 mum) and isolates CH-1, CH-3, and AT-1 produced medium (37.7 to 47.1 mum) while others gave the small size sclerotia (34.3 to 37.6 mum). Pathogenic variability of isolates was determined using five chickpea cultivars; ILC-263, C-727, Dasht, CM-2000 and Pb-1. On the basis of pathogen ic variability all the isolates showed almost same intensity of infection except AT-3 in pre emergence mortality while in post emergence mortality all cultivars showed resistant response for the isolate; of AT-2. Variation in infection was observed in all the isolates. Isolates DL-1, DL-2, CH-2, AT-1 and AT-2 were more aggressive and most of the cultivars were susceptible to these isolates. ILC-263, Dasht, CM-2000 and Pb-1 were resistant to CH-1, CH-3 and AT-3 isolates. The genotype ILC-263 was tolerant to all isolates except CH-3, AT-2 and AT-3. Results of biochemical analysis in S. rolfsii using slab apparatus Polyacrylamide Gel Electrophoresis provided a powerful tool for discrimination based genetic diversity in fungus proteins. A total of 14 bands were observed and all bands showed variation except 7, 9, and 13.