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A total of 2,276 isolates of Rhizoctonia solani obtained from diseased crops of 68 species was classified into anastomosis groups AG-1, AG-2-1, AG-2-2, AG-3, AG-4 and AG-5 by anastomosis test. Among the isolates, 1,091 isolates were identified as AG-1, 32b isolates as AG2-1, 191 isolates as AG-2-2, 71 isolates as AG-3, 505 isolates as AG-4, and 92 isolates as AG-5. Among the isolates of AG-1, 791 isolates were grouped as cultural type IA, 280 isolates as cultural type IB, and the others as cultural type IC. Among the isolates of AG-2-2, 112 isolates were grouped as cultural type IIIB, and the others as cultural type IV. Cultural types IA, IB and 1C of AG-1 were isolated from 7, 26 and 2 species of crops, respectively. AG-2-1 was isolated from 10 species of crops. Cultural types IIIB and IV of AG-2-2 were isolated from 7 and 3 species of crops, respectively. AG-3 was only isolated from Solanum tuberosum. AG-4 was isolated from 43 species of crops, and AG-5 from 13 species of crops. A single anastomosis group was isolated from each of 45 species of crops, but two or more than two anastomosis groups were isolated from each of the other crops. Cultural appearance of the isolates belonging to an anastomosis group or a cultural type was mostly distinct from that belonging to others, although cultural appearances of some anastomosis groups or cultural types were similar to one another. Optimum temperature for mycelial growth of AG-1, AG-2-2, AG-4 and AG-5 ranged from 26 to 30℃, and that of AG-2-1 and AG-3 from 22 to 26℃. Minimum temperature for mycelial growth of AG-2-1 was the lowest as 2∼3℃, that of AG-1(IA) and AG-4 was the highest as 10∼11℃, and that of the others ranged from 5 to 10℃. Maximum temperature for mycelial growth of AG-2-2(IIIB) was the highest as 36∼37℃, that of AG-2-1 was the lowest as 29∼30℃, and that of the others ranged from 31 to 36℃´. When the mycelial growth rates at 26℃ were compared, AG-1(IC) grew most rapidly, followed by AG-1(IA) and AG-1(IB), and AG-2-A grew most slowly.
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