Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: February 12, 2010
Publication Date: April 1, 2010
Citation: Ling, K., Fery, R.L. 2010. Virus Survey of Commercial Cowpea Fields in the U. S. and Evaluation of the Core of the USDA Cowpea Germplasm Collection for Resistance to Tomato Spotted Wilt Virus. HortScience. 45(4):504 Technical Abstract: Cowpea (Vigna unguiculata) is an important vegetable crop in the southern United States. Cowpea plants are susceptible to over 20 viruses and many of them are seed-borne. A survey was carried out to evaluate the current virus status in commercial cowpea fields in five States (MO, NM, SC, TN and TX). A total of 211 leaf samples were collected and used to test by enzyme-linked immunosorbent assay (ELISA) for the presence of 14 viruses. The following eight viruses were identified in the commercial fields: Alfalfa mosaic virus (AMV), Cucumber mosaic virus (CMV), Cowpea aphid-borne mosaic virus (CABMV), Cowpea chlorotic mottle virus (CCMV), Southern bean mosaic virus (SBMV), Tobacco mosaic virus (TMV), Tobacco ringspot virus (TRSV), and Tomato spotted wilt virus (TSWV). The survey results confirmed the presence of TSWV on cowpea in the U.S.; in addition to confirming the original report from New Mexico, TSWV was also found in Tennessee and Missouri. The incidence of CMV infection was high, especially in South Carolina, where all plants sampled were infected. However, incidence of viral infection in commercial cowpea fields by other viruses was low (1-4%). Probably due to the wide use of certified seeds in recent years, Blackeye cowpea mosaic virus was even not detected. The core of the USDA cowpea germplasm collection (677 accessions) was evaluated for TSWV resistance using a tomato strain of TSWV. The TSWV infections were restricted to the inoculated tissues (cotyledon or leaf); newly developed leaves on the inoculated plants did not exhibit TSWV symptoms. Future effort in screening should focus on using the cowpea-infecting strain of TSWV.