Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 26, 2009
Publication Date: May 1, 2010
Citation: Haynes, K.G., Wanner, L.A., Thill, C.A., Bradeen, J.M., Miller, J., Novy, R.G., Whitworth, J.L., Corsini, D.L., Vinyard, B.T. 2010. Common Scab Trials of Potato Varieties and Advanced Selections at Three U.S. Locations. American Journal of Potato Research. 86:261-276.
Interpretive Summary: Common scab is a serious soil-borne bacterial disease which can severely disfigure potato tubers. The incidence of common scab is increasing in potato growing regions. This study evaluated new potato varieties for their reaction to common scab in Maine, Minnesota, and Idaho. We found that some varieties were more resistant to common scab than others. We also found that the levels of resistance sometimes differed among these three locations. This information will be useful to growers in selecting new potato varieties to grow in their location.
Common scab (CS), caused by Streptomyces spp., is a soil-borne bacterial disease of potato tubers which may cause superficial, raised, or pitted lesions. The results of screening potato germplasm for severity of CS can be variable, necessitating testing over multiple environments. The purposes of this study were to evaluate advanced germplasm from public potato breeding programs in different regions of the United States for their reaction to CS, estimate broad-sense heritability for resistance, and identify clones with stable resistance. Seventeen to 23 clones per year were evaluated at each of three locations (ID, ME, MN) from 2002 to 2007. After harvest, each tuber was scored for the percent of surface area covered with lesions and the type of lesion. These scores were converted to an area index (MI) and a lesion index (LI). MI, LI, and the arcsine v proportion scabby tubers (PS) were analyzed as normally distributed responses. There were significant differences among clones for MI in two years, LI in five years, and PS in three years. There were significant clone x location interactions for MI and PS all six years, and LI in five years. Broad-sense heritability for MI, LI, and PS ranged from 0 to 0.78, 0.49 to 0.90, and 0.30 to 0.80, respectively. Evaluation at multiple sites remains important for characterizing the reaction of potato germplasm to CS.