Distribution and Identification of Colletotrichum Species Associated with Soybean Anthracnose/Pod Blight in Different Geographical Locations of Uttarakhand

Abstract

Background: The anthracnose/pod blight disease caused by Colletotrichum species, is considered as a major limitation in soybean cultivation worldwide, causing significant yield losses. This study was conducted to determine the prevalence of soybean anthracnose/pod blight in different geographical locations of Uttarakhand and to identify the Colletotrichum species associated with the disease. Methods: Roving survey was carried out in various soybean growing areas of Uttarakhand, covering 82 villages in 11 districts during kharif 2017 to 2019. In order to record the prevalence of the disease, incidence and severity were recorded periodically in soybean fields. From different surveyed locations, samples of anthracnose and pod blight were collected, isolated and identified on the basis of genetic analysis of the ITS region of rDNA. Result: The survey study revealed that disease was evident in all surveyed districts of Uttarakhand except district Haridwar. The pooled mean incidence and severity of pod blight infection in different districts ranged from 3.96 to 27.0 per cent and 2.04 to 15.69 per cent, respectively, maximum in the U. S. Nagar district and minimum in the Almora district. It was observed that disease incidence and severity decreased with rises in altitude with highly significant negative correlation of -0.89 and -0.89, respectively. Three distinct Colletotrichum species i.e., C. truncatum, C. cliviae (=C. cliviicola) and C. chlorophyti were identified through molecular characterization of the ITS-5.8S rDNA region (BLASTn queries), which were associated with soybean anthracnose/pod blight disease in Uttarakhand.