Karakterisasi Morfologi dan Molekuler Ganoderma spp. Penyebab Penyakit Busuk Pangkal Batang (BPB) dan Busuk Pangkal Atas (BPA) pada Tanaman Kelapa Sawit (Elaeis guineensis Jacq.)

Abstract

Sumatera is one of the regions with high productivity in palm oil (Elaeis guineensis Jacq.) production in Indonesia. However the sustainability of the palm oil industry in Indonesia could be threatened by the presence of basal stem rot (BSR) and upper stem rot (USR) which are the main diseases in oil palm cultivation in Sumatera. BSR and USR diseases are caused by pathogens from the same fungal genus, namely Ganoderma. There is still little information about variations in morphological characteristics and genetic diversity of Ganoderma pathogens that cause BSR and USR diseases in the field. This disease develops slowly and disease detection is usually done visually by looking at the presence of Ganoderma fruiting bodies (basidiocarp) on the infected oil palm trees. This study aims to characterize symptoms, describe morphology (both macroscopis and microscopic) and identify molecularly the diversity of pathogens that cause BSR and USR to determine the further disease control strategies. The study was conducted at Asian Agri Group plantations, which are spread across three provinces (Riau, North Sumatera and West Sumatera), Ganoderma Laboratory of the Research and Development Center of Asian Agri Group, Bahilang, Tebing Tinggi and at the Biomolecular Laboratory of the Royal Golden Eagle Technology Center (RGE-TC) in Pangkalan Kerinci, Riau from June 2023 to March 2024. The methods used include morphological description of fruiting bodies, macroscopic and microscopic morphological description of isolates, soil analysis from trees infected with Ganoderma, molecular identification using primers ITS1-ITS4 and ITS1F-LR3 as well as phylogenetic tree reconstruction to investigate the relationship between Ganoderma spp. species using MEGA 10 software. From this study, a total of 128 Ganoderma samples consisting of 120 BSR samples and 8 USR samples were characterized by the morphology of their fruit bodies. Of these, 69 samples were identified as Ganoderma boninense, which is the dominant species, however, phylogenetically, this species consists of several different yet closely related strains.