Anthracnose disease is a major constraint to yam production in tropical West Africa and anywhere the crop is cultivated. This study determined the cultural characteristics and growth rates of mycelia and also characterised 6 isolates of Colletotrichum gloeosporioides, the causal agent of the yam anthracnose disease, obtained from Dioscorea rotundata leaves, vines and setts in the Tolon District of Ghana. The cultural characteristics and mycelial growth rates of the isolates were determined on Potato Dextrose Agar (PDA). The C. gloeosporioides isolates were characterised using polymerase chain reaction technique with the universal primer pairs ITS1/ITS4 and NS1/NS2, C. gloeosporioides species specific primer pairs CgInt/ITS4 and CgLac-f/CgLac-r, and C. acutatum species specific primer pairs CaGlu-f1/CaGlu-r1 and Ca-f1/Ca-r1. Based on the PCR, six isolates of C. gloeosporioides with distinct cultural characteristics were obtained. There were no significant differences (P ≤ 0.05) in mycelial growth rates among the isolates. The C. gloeosporioides isolates produced characteristic band sizes on ITS1/ITS4, NS1/NS2, CgInt/ITS4 and CgLac-f/CgLac-r. None of the isolates produced a band on CaGlu-f1/CaGlu-r1 and Ca-f1/Ca-r1. The proper identification of C. gloeosporioides, the pathogen responsible for the D. rotundata anthracnose is important for the proper management of the disease.

 

Key words: Anthracnose disease, cultural characteristics, DNA band, morphological characteristics, Mycelial growth rate, polymerase chain reaction (PCR).