Identification of Sources of Resistance and Yield Loss Assessment for Aerial Blight and Anthracnose/Pod Blight Diseases in Soybean

Background: Aerial blight (Rhizoctonia solani Kuhn) and Anthracnose/pod blight (Colletotrichum truncatum) are important soybean diseases, affect most of the present varieties with varying intensity, in India. There are also few reports of resistance against both the diseases. Methods: To identify resistance, a set of 121 diverse soybean genotypes including six susceptible checks i.e. JS 93-05, JS 335, JS 72-280, Punjab 1, RKS 18 and VLS 58 were evaluated under high disease pressure field conditions during 2017, 2018 and 2019. Moreover, assessment of yield losses due to these diseases were also worked out in highly infected plants of susceptible checks. Result: It was observed that aerial blight (0.0-46.8 per cent) and anthracnose/pod blight (0.0-56.2 per cent) were affected soybean genotypes from R1 to R7 and V3 to R7 stages, respectively. The genotypes responded differently and showed absolute resistance to susceptible reaction. Out of 121 genotypes, only five genotypes i.e. JS 20-57, JSM 222, MACS 1407, PS 1611 and Cat 2126 B were found to be highly resistant against both the diseases. Per cent pod and yield losses were significantly correlated with varying severity of aerial blight (0.966** and 0.995**) and anthracnose/pod blight (0.957** and 0.995**), respectively. However, the highest yield loss of 41.0 and 64.8 per cent were recorded on 55.6 and 75.2 per cent disease index (at 90 days) of aerial blight and anthracnose/pod blight, respectively.