Morphological and molecular variability in Colletotrichum capsici causing anthracnose of chilli in Tamilnadu

Chilli (Capsicum annuum l.) is popular vegetable widely grown in the tropics, which is mainly attacked by fruit rot incited by Colletotrichum capsici. Twenty isolates of Colletotrichum capsici causing chilli anthracnose were collected from chilli cultivated area of Tamilnadu. The isolates were evaluated for their morphological and cultural characteristics, pathogenic variability on chilli fruits and genetic characterization using random amplified polymorphic DNA (RAPD – PCR). Among the twenty isolates, the isolate Cc₁ was significantly the most virulent one, which recorded the highest fruit rot intensity (69.9%) and leaves infection (63.2%) followed by Cc₂, Cc₄ while Cc₁₂ and Cc₁₅ were the least virulent. Mycelial growth and colony character of all the twenty isolates were recorded on PDA medium. The highest colony diameter was recorded in isolate Cc₁ (90 mm) followed by isolate Cc₂ (88 mm). The isolates Cc₁, Cc₂, Cc₉ and Cc₁₁ showed profuse sporulation on PDA medium. The isolates of C. capsici exhibited variation in respect of colony colour and growth pattern on PDA medium. The isolates Cc₁, Cc₂, Cc₃ and Cc₁₁ produced acervuli in a scattered manner, had fluffy and raised colonies. Molecular polymorphism generated by RAPD confirmed the variation of the different isolates and they were grouped into three clusters. However, morphological and RAPD grouping of isolates suggested no correlation among the test isolates.