Morphological and molecular variability in Rhizoctonia solani isolates infecting potato and rice

Twenty two different isolates of R. solani, 11 each of rice (sheath blight) and potato (black scurf) were collected from different rice and potato growing areas of Punjab. Variations among these isolates were observed in different morphological traits (radial growth, size of sclerotia, sclerotial pattern, aerial mycelium, colony colour, no. of nuclei per cell, sclerotial density and type of sclerotia). Anastomosis grouping of these isolates was done through PCR using different AG-group specific primers viz; AG 1-1A, 1B, 1C, AG2-1, AG2-2, and AG-3. All the potato isolates showed amplification with AG-3 group specific primers, while the rice isolates showed amplification with AG1-1A group specific primers.