1988 Volume 54 Issue 2 Pages 141-150
Twelve isolates of Rhizoctonia solani AG-1(IA) from each different location of Korea, four isolates of R. solani AG-1(IA) and three isolates of R. solani AG-2-2(IIIB) from several locations of Japan having different cultural ages were tested for the reaction and frequency of hyphal anastomosis by WA-cellophane culture. All the isolates except one made cytoplasmic (perfect) fusions without cell death or killing reaction and contact fusions in their self-anastomosis. One AG-2-2(IIIB) isolate made only contact fusions in its self-anastomosis, although it made non-cytoplasmic (imperfect) fusions and contact fusions at low frequency with two different AG-2-2(IIIB) isolates. Of the AG-1(IA) isolates, only the isolate WJB-5 from Korea made cytoplasmic fusions at 57.3% and 54.3% with the isolate 57-6 and HR-1 from Japan, respectively, and the others from Korea made non-cytoplasmic fusions at 47.3-68.0% and contact fusions at 0.7-18.0% with those from Japan. Five AG-1(IA) isolates from Korea including WJB-5 did not make cytoplasmic fusions each other, although non-cytoplasmic fusions and contact fusions occurred among them. The cytoplasmic fusion also did not occur in five pairings of the AG-1(IA) isolates from Japan except the pairing of 57-6 and HR-1. However, the cytoplasmic fusions which occurred between 57-6 and HR-1 occasionally showed abnormal forms of the fused cells, and their frequency was usually lower than that between WJB-5 and 57-6, or WJB-5 and HR-1. Cytoplasmic fusion did not occur in any pairing of three CFIs (cytoplasmic fusion isolates) and ten AG-1(IA) isolates from the same geographic origins of two CFIs, but non-cytoplasmic fusion and contact fusion occurred. The incident property and frequency of cytoplasmic fusion among the CFIs were not varied by subculturing the isolates on PDA. The results revealed that the characteristics in hyphal anastomosis of R. solani AG-1(IA) were not related to the locality and cultural ages of the isolates.