POTENTIAL FOR SYMBIOSIS OF RHIZOCTONIA-SOLANI AND BINUCLEATE RHIZOCTONIA WITH SEEDS OF SPIRANTHES-SINENSIS VAR AMOENA IN-VITRO

Rhizoctonia isolates obtained from non-orchid sources were tested for symbiotic ability with seeds of Spiranthes sinensis var. amoena in vitro. All or some isolates of Rhizoctonia solani anastomosis group (AG)-1, AG-2-1, AG-2-2, AG-3, AG-4, AG-5, AG-6, AG-7, AG-8, and AG-BI induced symbiotic germination of the orchid seeds. In binucleate Rhizoctonia anastomosis groups, also all or some isolates of AG-A, AG-Ba, AG-Bb, AG-B, AG-C, AG-D, AG-E, AG-F, AG-G, AG-H, AG-I, AG-K, AG-L, AG-M, AG-O, AG-P and AG-Q, induced the symbiotic germination. However, no germination occurred when the seeds were inoculated with Sebacina vermifera (R. globularis) and Waitea circinata (R. zeae, and R. oryzae) in vitro.