Interception of Seed-transmitted Viruses in French Bean Germplasm Imported During 2002 - 2003
The quarantine processing of 178 accessions of soybean [Glycine max (L.) Merr.] germplasm imported into India during 2003 and 2004 revealed the presence of Alfalfa mosaic virus (AMV), Bean common mosaic virus (BCMV), Bean yellow mosaic virus (BYMV). Cowpea aphid-borne mosaic virus (CABMV), Cucumber mosaic virus (CMV), Southern bean mosaic virus (SBMV), Soybean mosaic virus (SMV) and Tobacco ring spot virus (TRSV) in accessions from Asian Vegetable Research and Development Center (AVRDC) Taiwan, International Institute of Tropical Agriculture (IITA) Nigeria, Brazil, Myanmar and USA. The virological testing methods employed include visual inspection, growing-on test, electron microscopy and enzyme-linked immmunosorbent assay. Shriveled, small, discoloured and mottled seeds found in 38 accessions were discarded and incinerated. During growing-on test, initial trifoliate leaves showed various symptoms viz.. mild to severe mosaic, crinkling, blistering and leaf distortion in 1–4 weeks old plants of 84 accessions. Flexuous virus particles measuring 700–900 nm were observed in the seven accessions tested, which were showing mild to severe mosaic symptoms. AMV, BCMV, CABMV, CMV, SBMV and TRSV are intercepted in soybean germplasm for the first time. Seed-transmitted CABMV and SBMV are as such not reported on soybean in India so far. Hanest from only virus-free plants was released to the indenters. The risk of introduction of eight seed-transmitted viruses and strains thereof was thus eliminated.