Vol. 11, Issue 7 (2022)

Author(s):
Narasimha Rao S, Bhattiprolu SL, Prasanna Kumari V and Vijaya Gopal A

Abstract:
Colletotrichum lindemuthianum was isolated from 95 samples of anthracnose infected field bean, collected from nine major field bean growing districts in five Agro Climatic Zones of Andhra Pradesh. Thirty six isolates from stem bits collected from nine locations, eight isolates from pods and leaves of four different locations were screened to study the cultural and morphological variability. Cultural variations with respect to colony morphology, radial growth, colony colour, colony reverse and mycelial growth pattern and growth rate were examined by growing them on potato dextrose agar. The isolates varied in their cultural behaviour ranging from cottony to fluffy, mostly suppressed with regular to irregular margin and dark black, white and olive brown colony colour. Significant differences were noticed among the isolates with respect to mycelial growth ranging from 36.10 to 88.70mm. It was noticed that olive brown colour isolates showed slow growth rate compared to the other isolates. Morphological variations in spore dimensions (both in length and width, ratio of L:W), number of oil globules, spore shape and sporulation were recorded. The acervuli were embedded, isolates under study mostly produced pinkish acervuli on PDA except CI-2 and CI-4, which had pink to orange colour. Conidia were hyaline, single celled and most of the isolates possessed the cylindrical shape with one or both ends are pointed (12 isolates). Conidia of C lindemuthianum isolates contained zero to three oil globules per conidia.