Isolasi dan Identifikasi Cendawan Terbawa Benih Kakao Hibrida

Abstract

Seed is the basic component influencing the productivity of cacao plantation Healthy seed is the most Important factor in determining the success of cacao producuvity. Moisture content of cacao seeds is quite high potentially to cause fungi infection, which can further reduce seed quality and cacao producution. The research aimed at isolating and identifying several seedborne fungi on hybrid cacao. The study was conducted at main nursery of Indonesian Coffee and Cocoa Research lnsutute Jember, Laboratory of Microbiology, Indonesian Biotechnology Research lnsutitute for Estate Crops, and the Laboratory for Biological Control of IPB Bogor from June to October 2008. Research used hybrid cacao seeds derived from crossing between TSH 858 x SCA 6, and the experiment was arranged using completely randomized design with three replicates. Cacao seeds were grown on three media, i.e. water agar (WA), potato dextrose agar (PDA), and filter paper (KS). Infection rates on the seedlings were observed every day and analyzed using ANOVA followed by Duncan's multiple regression test (DMRT). Fungi were isolated, cultured, purified, and identified using the identification keys The highest rate of seedborn fungai infection occured on fourth (35.00%) and fifth (51.67%) days on PDA media. A total of 13 species of seedborn fungi on hybrid cocoa were idetified by using WA and PDA media, as well as 8 other species by using KS. The 13 seedborne fungi potentially reduce seed physiological quality and cacao productivity. These fungi need to be further tested because each has its own pathogenic, saprophytic, or antagonostic properties towards other fungi on cacao seeds. Predominant seedborn fungi on hybrid cacao were Aspergillus spp., Penicillium chrysogemum, Coletotricum acutatum, Curvularia geniculata, and Fusarium spp. The fungi suspected harmful were Aspergillus spp., Coletrotihum acutatum, Curvularia geniculata, Fusarium spp., Phoma glomerata, and Macrophoma sp., and those suspected pathogenic were Aspergillus flavus, Aspergillus ochraceus, Cladosporium herbanum, Curvularia geniculata, Fusarium oxysporum, Phoma glomerata, and Macrophoma spp.