ANASTOMOSIS GROUPS OF Rhizoctonia solani FROM POTATO AND SURVEY OF SOMATIC COMPATIBLE GROUPS BY MORPHOLOGICAL CHARACTERS AND RAPD MARKER

Fifty-eight isolates of Rhizoctonia solani were isolated from infected subterranean potato stems and tuber in Hamedan and Kurdistan provinces and their variability studied by using morphological and molecular markers. All isolates were multinucleate and among them, 56 isolates were belonging to AG-3, one isolate belonging to AG-4 and one isolate did not anastomose to any of available anastomosis group tester isolates in this study. In somatic compatible group determination, AG-3 isolates paired on PDA amended with 1% charcoal. Out of 56 isolates, 43 somatic compatible groups were obtained in which 35 groups possessed an isolates alone, one group comprising four isolates all collected from fields of Qorveh as largest group (EE) and seven remaining groups each one was comprising two or three isolates. Pathogenicity severity of isolates belonging to AG-3, as a group, on potato sprouts, was higher than AG-4 isolate and unknown isolate did not produce any lesion or symptom of disease on potato sprouts. Finely, genetic diversity of four selected somatic compatible groups including E, F, T and EE studied by RAPD marker. Data analyzed by NTSYS software using UPGMA method and Jaccard coefficient. Isolates divided in four clusters with a minimum similarity coefficient of 42%. Results of molecular study supported and verified morphological results.