Mating Compatibility and Restriction Analysis of Ganoderma Isolates from Oil Palm and Other Palm Hosts

Mating compatibility and restriction analyses of Internal Transcribed Spacer (ITS) regions were performed to determine the relations between Ganoderma boninense, the most common species associated with basal stem rot in oil palm and Ganoderma isolates from infected oil palm, two ornamental palms, sealing wax palm (Cyrtostachys renda) and MacArthur palm (Ptychosperma macarthurii), an isolate from coconut stump (Cocos nucifera), Ganoderma miniatocinctum, Ganoderma zonatum and Ganoderma tornatum. The results showed that G. boninense was compatible with Ganoderma isolates from oil palm, G. miniatocinctum and G. zonatum, Ganoderma isolates from sealing wax palm, MacArthur palm and coconut stump. G. boninense was not compatible with G. tornatum. Therefore, the results suggested that the G. boninense, G. miniatocinctum, G. zonatum, and Ganoderma isolates from oil palm, ornamental palms and coconut stump could represent the same biological species. In performing a restriction analysis of the ITS regions, variations were observed in which five haplotypes were generated from the restriction patterns. An unweighted pair-group method with arithmetic averages (UPGMA) cluster analysis showed that all the Ganoderma isolates were grouped into five primary groups, and the similarity values of the isolates ranged from 97% to 100%. Thus, a restriction analysis of the ITS regions showed that G. boninense and the Ganoderma isolates from other palm hosts were closely related. On the basis of the mating compatibility test and the restriction analysis of the ITS regions performed in this study, a diverse group of Ganoderma species from oil palm and other palm hosts are closely related, except for G. tornatum and Ganoderma isolates from tea and rubber.