DNA base sequence homology in Rhizoctonia solani Kuehn. VI. Genetic relatedness among seven anastomosis groups.

DNA base sequence homology among isolates of different anastomosis groups (AG-1, AG-2, AG-3, AG-4, AG-5, AG-6 and AG-7) in Rhizoctonia solani was determined by DNA-DNA reassociation kinetics. DNA homology among isolates of these anastomosis groups showed consistently low values (0 to 33.7%). These results suggest that each of these anastomosis groups is a genetically isolated group. The significance of classification of R. solani into groups on the basis of anastomosis behaviours is stressed.