Biosecuring India from seed-transmitted viruses: The case of quarantine monitoring of legume germplasm imported during 2001–2010

The quarantine processing of 4, 836 germplasm accessions of different legume crops viz., Glycine max (951), Lathyrus spp. (15), Phaseolus vulgaris (1592), Pisum sativum (533), Vigna marina (1), V. mungo (7), V. subterranea (2), V. radiata (251), V. umbellata (7), V. unguiculata (617), Vicia spp. (87) and Vicia faba (773) imported from different countries including CGIAR centres during 2001–10 revealed the presence of 29 viruses viz., Alfalfa mosaic virus (AMV), Arabis mosaic virus (ArMV), Bean common mosaic virus (BCMV), Bean common mosaic necrosis virus, Bean pod mottle virus (BPMV), Bean yellow mosaic virus, Broad bean stain virus (BBSV), Broad bean wilt virus (BBWV), Cherry leaf roll virus (CLRV), Cowpea aphid-borne mosaic virus (CABMV), Cowpea mottle virus (CPMoV), Cowpea mild mottle virus, Cowpea mosaic virus, Cowpea severe mosaic virus (CPSMV), Cucumber mosaic virus, Grapevine fan leaf virus (GFLV), Pea enation mosaic virus (PEMV), Pea seed-borne mosaic virus (PSbMV), Peanut mottle virus (PeMoV), Raspberry ring spot virus (RpRSV), Southern bean mosaic virus (SBMV), Soybean mosaic virus (SMV), Tobacco necrosis virus (TNV), Tobacco rattle virus (TRV), Tobacco ring spot virus, Tobacco streak virus (TSV), Tomato aspermy virus, Tomato black ring virus and Tomato ring spot virus (ToRSV). Eight viruses viz., BBSV, BPMV, CLRV, CPMoV, CPSMV, PEMV, RpRSV and ToRSV are not reported from India and 14 viruses viz., AMV, ArMV, BBWV, BCMV, CABMV, GFLV, PeMoV, SBMV, SMV, TBRV, TNV, TRV and TSV are known to occur in India on other crops but not on the hosts on which they were intercepted, hence these 22 viruses are of quarantine significance for India. A total of 1238 accessions was found infected by one or more of these viruses. Testing methods for detection of viruses include visual inspection, growing on test, electron microscopy and enzyme-linked immunosorbent assay. Harvest from only virus-free plants (4, 833 accessions) was released to the indenters. The risk of introduction of 29 seed-transmitted viruses or their strains was thus eliminated.