Submitted to: Plant Disease
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/23/2005
Publication Date: 1/1/2006
Citation: Whitworth, J.L., Nolte, P., Mcintosh, C., Davidson, R. 2006. Effect of potato virus y on yield of three potato cultivars grown under different nitrogen levels.. Plant Disease. 90:73-76 Interpretive Summary: Effect of Potato virus Y on yield of potato grown under different nitrogen levels. Potato virus (PVY) is a yield limiting virus in potatoes. Three popular cultivars used for table stock production were evaluated under different nitrogen fertilizer levels. The cultivar yields were compared for PVY infected plants and non-infected plants. Two cultivars, Russet Norkotah and CO80011-5 have mild symptom expression when infected with PVY, while Russet Burbank has stronger, more typical symptoms. Yield reduction was the same in the first two cultivars and much less when compared with Russet Burbank. This study shows that adding extra fertilizer to compensate for the yield reduction (even in mild symptom cultivars) does not make up for the yield reduction caused by PVY. In addition, it shows that just increasing nitrogen fertilizer with non-infected plants does not always increase yield, there is an optimum fertilizer level for each cultivar.
Technical Abstract: Potato Virus Y (PVY) limits yield in potato production. Typical foliar symptoms can include veinal necrosis, leaf drop, and a mosaic pattern sometimes accompanied by leaf roughness. Russet Burbank produces typical PVY symptoms, while the variety Russet Norkotah expresses mild, almost latent symptoms. Previous studies have shown that PVY reduces yield in many varieties. Yield can be also be influenced by nitrogen fertilizer levels. This study was done in to determine if increased nitrogen mitigates yield reduction caused by PVY. This study used Russet Norkotah, CO80011-5, and Russet Burbank and compared plots of 7 healthy and 7 PVY infected plants with three replications and at three nitrogen levels in 1995 and 1996. Plants were serologically tested during the growing season to confirm PVY status. At harvest, data was collected on plant yield and tuber number. Significant yield reduction existed between healthy and infected plots in all varieties and generally regardless of nitrogen levels. PVY yield reduction was similar (approx. 38%) in the mild symptom expression clones of Russet Norkotah and CO80011-5, while Russet Burbank was 63.5%. Conclusions are that increased nitrogen can influence total yield, but doesn't significantly mitigate the yield reduction due to PVY.