Identification of host plant resistant to Dolichos Yellow Mosaic Virus (DYMV) in Dolichos bean (Lablab purpureus)

Three hundred Dolichos bean (Lablab purpureus) genotypes were screened against Dolichos Yellow Mosaic Virus (DYMV) disease. Initial screening was done under field conditions where disease incidence was calculated for each genotype. Subsequently, selfed progenies of 34 symptomless lines were challenged by sap inoculation under field conditions, out of which only three genotypes, viz. VRSEM-894, VRSEM-887 and VRSEM-860 did not show any symptoms. Using root stalk of susceptible genotype (Ankur Goldy), these three putative symptomless genotypes were further challenged by grafting. The resistant reactions of VRSEM-894, VRSEM-887 and VRSEM-860 were confirmed as even after 60 days of successful grafting, no viral symptom appeared on all the grafted plants of these genotypes. When subjected to PCR amplification with DYMV coat protein gene specific primer, these three symptomless genotypes did not show any amplification, suggesting that there was no infection of Dolichos Yellow Mosaic Virus in those genotypes.