Host plant resistance against Rhizoctonia solani AG 1-IB causing foliar blight of soybean in Meghalaya

Abstract

The present investigation was carried out to determine the host plant resistance against Rhizoctonia solani causing foliar blight of soybean in Meghalaya. Twelve isolates were used for molecular characterization using specific primers to determine anastomosis groups and sub-groups. The isolates RL1, Rim_1, RL2, RL4, RL5, RL6, RL7, RL8, RLR, RL9 and RL10 belonged to AG 1-IB. Only one isolate RL3 (product size ~ 265 bp) belonged to AG 1-IA. In advanced varietal trial (AVT) 1, varieties/lines KDS 780 and DSb 28-3 had low natural incidence (2.5 and 7.5%, respectively) and low disease severity (25 and 23.3%, respectively), while varieties/lines JS 20-98 and JS 97-52 had high natural incidence (35 and 52.5%, respectively) and high disease severity (62.7 and 80.9%, respectively). In AVT 2, varieties/lines SL 955 and SL 983 had low natural incidence (2.5 and 5%, respectively) and low disease severity (5 and 15%, respectively), while varieties/lines Himso 1685 and JS 97-52 had high natural incidence (35 and 47.5%, respectively) and high disease severity (63.6 and 65.1%, respectively). Twenty varieties/lines from AVT 1 and twelve varieties/lines from AVT 2 were used for in vitro screening against R. solani. In AVT 1 (leaves) varieties/lines JS 20- 96 and DSb 28-3 were less susceptible (Area under disease progress curve AUDPC = 53.6 for both). In AVT 2 (leaves) varieties/lines DSb 25 and VLS 86 were less susceptible (AUDPC = 37.0 and 49.6, respectively). In AVT 2 (pods) varieties/lines VLS 86 and DSb 23-2 were less susceptible (AUDPC = 119.3 and 101.1, respectively).