Molecular Profiling Ecofriendly Trichoderma Biological Control Agent of Yam Tuber Microbial Rot in Northern Nigeria

Abstract

This research on isolation and identification of yam rot pathogen fungi from North central Nigeria was carried out to investigate some fungal species associated with yam rot using white yams (Dioscorea rotundata) obtained from Adamawa State, Benue State and Plateau State (Jos) Nigeria. Seven fungi species which cause yam rot were isolated during this study, namely: Aspergillus flavus, Aspergillus niger, Penicillium citrinum, Penicillium echinulatum, Penicilum purpurogenum, Trichoderma spp and Trichophyton spp. Trichoderma yunnanense strain RCBBR_GA1 OP8008361 was identified molecularly. Pathogenicity test carried out confirmed these organisms as the pathological agent of the rot. A. niger statistically has the highest frequency of occurrence (100%). The least encountered fungal species were the P. citrinum (16.6%), P. purpurogenum (33.3%) and Trichophyton spp (33.3). Percentage growth inihibition of A. flavus, A. niger, P. citrinum, P. echinulatum, P. purpurogenum, Trichoderma spp and Trichophyton spp was carried out and they showed varying degree of inhibition. However, Trichopyton spp shows the highest growth of inhibition at 96 hours (41.4%) and 120 hours (73.7%). Trichoderma exhibited the highest control of the isolates (80 mm). Trichoderma inhibited mycelia extension growth of A. flavus (25 mm), A. niger (25 mm), P. citrinum (23 mm), P. echinulatum (23 mm), P. purpurogenum (24 mm) and Trichopyton spp (22 mm) at 96 hours. The result shows that Trichoderma was able to inhibit the growth of the pathogenic fungi, which are associated with yam rot. Fungal isolates from yam rot were examined morphologically and microscopically and the nature of rot was varied. It is recommended that enzymes from Trichoderma should be extracted and applied for reduction of microbial rot of yam tubers.