Sweet potato virus disease (SPVD) is the most devastating virus disease on sweetpotato [Ipomoea batatas (L.) Lam] world wide, especially in East Africa. However, weather it is present in the U.S. is unknown. SPVD is caused by co-infection of sweetpotato feathery mottle virus (SPFMV) and sweetpotato chlorotic stunt virus (SPCSV). Presence of two other potyviruses, sweetpotato virus G (SPVG) and Ipomoea vein mosaic virus (IVMV) has also been confirmed in the U.S. Sweet potato leaf curl virus (SPLCV), a whitefly (Bemisia tabaci) transmitted Begomovirus, also has the potential to spread to commercial sweetpotato fields and poses a great threat to the sweetpotato industry. The U.S. collection of sweetpotato germplasm contains about 700 genotypes or breeding lines introduced from over 20 different countries. Newly introduced sweetpotato germplasm from foreign sources are routinely screened for major viruses with serology and graft-transmission onto indicator plants (Ipomoea setosa). However, a large portion of this collection including heirloom cultivars or old breeding materials has not been systemically screened for these major sweetpotato viruses. In this study, a total of 69 so-called heirloom sweetpotato PI accessions were evaluated for their virus status. We used Real-time PCR to detect five sweetpotato viruses, including four RNA viruses (SPCSV, SPFMV, SPVG, and IVMV) and one DNA virus (SPLCV). A multiplex Real-time RT-PCR system was developed to detect three RNA viruses (SPFMV, SPVG, and IVMV). Preliminary data indicated that about 15% of these heirloom sweetpotato germplasm carried at least one of these viruses tested. Details on virus infection status will be presented.
K.S. Ling, C.A. Clark, C. Kokkinos, J. R. Bohac, S.S. Hurtt, R. L. Jarret, and A. G. Gillaspie
A.G. Gillaspie, O.L. Chambliss, R.L. Fery, A.E. Hall, J.C. Miller Jr., and T.E. Morelock
The Vigna Crop Germplasm Committee has established a core subset for the USDA cowpea germplasm collection. The subset consists of 9.3% (700 accessions) of the 7525 accessions currently contained in the collection. The subset was selected on the basis of country of origin, taxonomic characteristics, and known disease and pest resistance characteristics. Theoretically, the lines in the subset represent the genetic diversity present in the entire collection. A listing of the accessions in the subset is available from the Vigna germplasm curator (A.G. Gillaspie). The listing can also be accessed through the USDA's Germplasm Resources Information Network (GRIN).