Screening of Clusterbean Germplasm for Resistance against Xanthomonas axonopodis pv. cyamopsidis Causing Bacterial Blight Disease in Clusterbean

The expermintent was conducted during kharif 2018 and 2019 crop season at experimental farm, Rajasthan Agricultural Research Institute, Durgapura to test the resistance of one hundred clusterbean germplasm/ cultivars. Host plant resistance is an ultimate tool to keep away the disease from the crop. It is a simple, cheap and ecofriendly approach for the management of disease. Therefore, one hundred clusterbean germplasm were screened against bacterial blight disease (Xanthomonas axonopodis pv. cyamopsidis) under artificial epiphytotic condition to find out the source of resistance. Per cent disease index (PDI) of each genotype was recorded at pre-flowering and maturity stage by visual scoring as per the standard continuous rating 0-5 scale. On the basis of pooled data of 2018 and 2019, among the total one hundred germplasm, only two germplasm namely RGr-16-2 (RGC-936×RGC-1055) and RGr-16-11-5 (RGC-1025×RGC-197) were found resistant with minimum Pre cent disease intensity 7.77, 9.44, 9.44 and 10.00 at pre flowering and maturity stages respectively, thirty germplasm showed moderate resistant (MR), sixty seven germplasm found moderately susceptible (MS), one germplasm namely RGr-17-16-2 (GG-1×RGC-936) found susceptible (S) with maximum PDI 51.11 and 52.22 at pre flowering and maturity stage, respectively. None of the germplasm was found completely free from the disease and highly susceptible (HS) against bacterial blight.