Serological Indexing of Major Commercial Cultivars and Rootstocks to Ascertain Their Sanitary Status

Abstract

Viral diseases can constrain stone fruit nursery production and compromise the sanitary quality of propagating material. This study assessed the sanitary status of available stone fruit germplasm maintained at selected nurseries in Solan and Shimla districts of Himachal Pradesh, India. Surveys were conducted during the active growing season of 2021, and representative plants of peach, plum, apricot, nectarine, and cherry cultivars were evaluated. The germplasm was visually examined and serologically indexed for Prunus necrotic ringspot virus (PNRSV), the most prevalent virus reported in the surveyed nurseries, using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). Optical density values recorded at 405 nm were used to classify the tested plants as positive or negative relative to the assay controls. PNRSV-positive reactions occurred in several cultivars across the surveyed locations, and peach cultivars frequently yielded positive results. In contrast, all sampled plants of the plum cultivar Red Beaut at Krishi Vigyan Kendra, Kandaghat, and the plum cultivar Black Amber at the Experimental Farm and Model Farm of Dr Y. S. Parmar University of Horticulture and Forestry, Nauni, tested negative for PNRSV under the conditions evaluated. These cultivars may represent candidate material for further confirmation before use in clean stock development. Repeated indexing across seasons and molecular confirmation are required before large-scale propagation. The findings provide a location-specific assessment of nursery sanitary status and support continued monitoring of stone fruit planting material.