CHARACTERIZATION OF ANASTOMOSIS GROUP-11 (AG-11) OF RHIZOCTONIA-SOLANI

Isolates of Rhizoctonia solani anastomosis group 11 (AG-11) were colle cted in Western Australia and Arkansas. Some isolates from each locati on fruited on 1.5% water agar, 2% V8-juice agar, and soil overlay plat es and produced sexual structures typical of Thanatephorus cucumeris. Mycelium of isolates of AG-11 growing on potato-dextrose agar was whit e to light tan when young, but became brown to dark brown with age. Co ncentric rings of dark and light mycelium were visible in most culture s. Mature sclerotia were tan to light brown and were scattered over th e agar surface. No anastomosis reactions (C0) were observed between pa ired isolates of AG-11 and anastomosis groups 1, 3-7, 9, and 10. Cl an astomosis reactions were observed between some isolates of AG-11 and s ome isolates of AG-2, -8, and -BI, indicating a distant or ''bridging' ' anastomosis relationship with these three AG. Isolates of AG-11 1 we re auxotrophic for thiamine. Isolates of AG-11 are known to damage lup ine, soybean, and other plants in the field, and in greenhouse and gro wth chamber studies were shown to damage other crops, including cotton , radish, wheat, and potato.