Accumulation of mineral elements in tuber periderm of potato cultivars differing in susceptibility to common scab

Concentrations of Ca, P, K, Mg, Al, Fe, Mn, Cu and Zn were determined in healthy tuber peelings of cultivars less (Karin, Sante and Symfonia) and more (Agria, Desiree and Tomensa) susceptible to common scab when grown at two sites that differed in the level of scab incidence. The accumulation of some elements was significantly influenced by site, year, cultivar, maturity and the age of tuber periderm. At both sites, Ca and P in periderm tissue declined but Mg increased during the growing season. The Ca/P ratios in tuber periderm of all cultivars greatly decreased 83 days after planting. Concentrations of mineral elements measured at harvest may not reflect conditions present during the infection period, and consequently may not be related to scab incidence or severity.