|Hamm, P - OREGON STATE UNIV|
|Hane, D - OREGON STATE UNIV|
|Jaeger, J - OREGON STATE UNIV|
|Shiel, P - APHIS, RALEIGH, NC|
|Berger, P - APHIS, RALEIGH, NC|
|Thornton, R - WASHINGTON STATE UNIV|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 30, 2006
Publication Date: August 1, 2006
Citation: Crosslin, J., Brown, C.R., Hamm, P.B., Hane, D.C., Jaeger, J., Shiel, P.J., Berger, P.H., Thornton, R.E. 2006. The occurrence of pvy(o), pvy(n), and pvy(n:o) strains of potato virus y in potato seed lot trials in washington and oregon.. Plant Disease. 90:1102-1105. Interpretive Summary: Potato virus Y (PVY) is an economically important pathogen of potatoes wherever the crop is grown. The virus exists as a number of biological types, or strains, that differ in their effects on potatoes and certain other plants, like tobacco. The ordinary strain of the virus, PVYO, causes mild symptoms in potato and tobacco. The tobacco necrotic strain, PVYN, causes very mild or no symptoms in potato foliage and a systemic necrosis in tobacco. Another strain, PVYN:O also causes systemic necrosis in tobacco and relatively mild symptoms in most varieties of potatoes. In addition to causing reductions in yield, the PVYN and PVYN:O stains are known to cause symptoms in potato tubers, thus reducing the quality of the crop. The primary source of PVY in a commercial field is infection of the seed pieces. For this reason it is important to determine how widespread the various PVY strains are in commercial seed lots. In this paper we investigated the occurrence of PVY is hundreds of seed lots from several states and Canadian provinces. Results indicate that PVY is widespread in commercial seed lots. The data also show that the incidence of the PVYN:O strain in particular is increasing in seed lots. This study shows that the current efforts to reduce the incidence of PVY in seed lots are not effective and that additional measures need to be taken to reduce the impact of this important virus to potato production.
Technical Abstract: A total of 960 and 286 seed lots from locations across North America were planted in trials in Washington and Oregon, respectively, in 2001-2003 and tested for the presence of various strains of Potato virus Y (PVY). The incidence of PVYO-infected lots averaged 16.4 and 25.9% between the Washington and Oregon trials, respectively. There was a general trend of increasing incidence of the PVYO, PVYN:O, and PVYN strains during this period as evidenced by more infected cultivars, sites of seed origin, and number of seed growers providing infected lots. In particular, there was a dramatic increase in the percentage of lots found to contain the PVYN:O strain between 2001 and 2003. In 2003, PVYN:O was detected in seed lots originating in eight states and three provinces. The increased incidence of PVYN:O is likely due to the difficulty in identifying this strain. These data document the increasing importance of PVY to potato production in the United States and suggest that current measures to reduce the incidence of this virus are inadequate.