Sweet potato feathery mottle virus effects on yield and root quality of harvested sweet potato roots
Bryan, A.D.; Yencho, G.C.; Schultheis, J.R.; Pesic Vanesbroeck, Z.
Phytopathology 91(6 Suppl): S12
The effects of SPFMV on yield and root quality were evaluated on three, initially virus-free (control) and virus-infected mericlones of cultivars 'Beauregard' and 'Hernandez' in field tests in 2000. Virus infected plants were obtained by graft-inoculating virus-free plants with SPFMV. The test was arranged in a split-plot design with five replications, with initial presence or absence of SPFMV being the whole plot treatment and mericlone as the subplot treatment. Weekly monitoring of foliar virus symptoms indicated that all virus-free plants were infected by harvest. Most plants became symptomatic two weeks following a major peak in aphid (Aphis gossypii and Myzus persicae) flights. SPFMV was confirmed by NCM-ELISA in each treatment. Roots from virus-infected treatments had increased length/diameter ratios and lower yields (4-32 percent) than controls. The results from this test indicate that decrease in yield and root quality can be attributed to SPFMV-infected planting stocks rather than in-season infection of plants.