康乃馨莖腐病菌之融合菌群與病原性的測定

Abstract

Eighty isolates of Rhizoctonia spp. were collected from stem rot and root rot of carnation. Among them, 94% were identified as R. solani and 6% as binucleate Rhizoctonia-like fungi (BRLF). About 2% of R. solani were assigned to AG-i, 75% to AG-4, 8% to AG-6 and 2% to AG-7. About 6% did not anastomose with any of the testers, and no isolates were assigned to AG-2, AG-3, AG-5 and AG-BI. Pathogenicity test showed that AG-1, AG-4, AG-6 and AG-7 isolates could cause 80%, 95%, 70% and 100% mortality on cultivar Raggio, and 80%, 90%, 100% and 100% mortality on Murcia, respectively. However, only 10% and 5% wilt of Raggio and Murcia were caused by BRLF. The results indicated that AG4, AG-4, AG-6 and AG-7 of R. solani were pathogenic to carnation (cultivar: Raggio and Murcia); but BRLF isolates were weakly pathogenic.