Plant Virology Lab, CSIR (Institute of Himalayan Bioresource Technology), Palampur-176061
National Symposium on Strategic Issues in Plant Pathological Research held at Department of Plant Pathology, CSK HP Krishi Vishvavidayalaya, Palampur on November 24–25, 2011
Apple is the major commercial horticulture crop in Himachal Pradesh (HP) and other hill states of Jammu & Kashmir, Uttarakhand and some parts of Northeastern states of India. In order to gather data on health status and incidence of virus and virus-like pathogens in apple orchards of HP, survey was conducted in the month of June, 2010 in Hatkoti, Rohru, Kuthara, Jubbal and Khadapathar areas of Shimla district. A total of 250 samples were collected from various rootstocks and scion combination viz. MM-106 bearing scion Starkrimson (SC), MM-106 Silver spur (SP), MM-106 Bright and Early (B&E), MM-109 Vance (WS), MM-111 Vance (WS), MM-109 Oeragon spur, MM-111 Oeragon spur, EM-7A Red chief (RC), M26 Bright and Early (B&E), and MM-106 Top red (TR). These samples were analyzed for detection of Apple chlorotic leaf spot virus (ACLSV), Apple mosaic virus (ApMV), Apple stem grooving virus (ASGV), Apple stem pitting virus (ASPV) and Apple scar skin viroid (ASSVd) with the help of NASH (Nucleic acid spot hybridization), ELISA (Enzyme linked immune-sorbent assay) and RT-PCR (reverse transcription-polymerase chain reaction). 117 samples were found to be infected in NASH, of which 37.6% were singly infected and in 63.2% exhibited mixed infection of above. Among these ASSVd was predominant with an incidence of 27.6% followed by ASPV (17.6%), ACLSV (16.8%), ApMV (15.2%) and ASGV (12.8%). In all root stock and scion combinations, viral and subviral pathogens were detected; retrieving that no one combination is resistant to these pathogens. Their analysis by ELISA resulted in identification of 50 positive samples showing infection of ACLSV, ASPV, ApMV and ASGV. Results of NASH and ELISA were validated by RT-PCR.
