Optimization of sprout seed abrasion method for efficient inoculation of leaf crinkle disease in urdbean [Vigna mungo (L.) hepper]

Urdbean leaf crinkle is one of the serious diseases of urdbean [Vigna mungo (L.) Hepper] which is caused by an ungrouped virus called Urdbean leaf crinkle virus (ULCV). The disease is highly seed transmissible under natural conditions and in experimental conditions it is mechanically transmitted through sap inoculation.

The aim of this study was to standardize the protocol for sap inoculation by sprout seed abrasive method by comparing the effects of different inoculation methods, such as pin prick and without pin prick, with 0.05M potassium phosphate buffer (pH 7.0) supplemented with additives and abrasives and to further validate the standardized protocol upon different urdbean genotypes.

This is the first effort on the optimization of protocol in which, pin pricking as inoculation method with potassium phosphate buffer (0.05M, pH 7.0) supplemented with 0.15% sodium sulfite+0.01M 2-Mercaptoethanol and 1% celite+2% carborundum showed 100% transmissibility foremost at 2^nd trifoliate stage and further validation with various urdbean genotype resulted in percent transmission ranging from 92 to 100% which evinces the efficacy and repeatability of the methodology.