Site, Year and Cultivar Effects on Relationships Between Periderm Nutrient Contents and Common Scab Severity
Abstract
Common scab (CS) severity was assessed in relationship to mineral contents of potato periderm in 18 cultivars varying in maturity period and CS susceptibility. Two field experiments, one repeated in 3 years, were conducted.
The effect of site, cultivar and growing period on the disease severity was always significant but not that of year to year variability. Zn, Mn and Fe periderm contents were related to site, while Ca content to cultivar effects.
In both experiments, the CS severity was positively correlated to calcium and negatively to phosphorus periderm content, while correlations of CS severity to other nutrients were dependent on site or year. Since soil pH, Ca and P soil contents were not different between sites, relatively small differences in other soil chemical characteristics combined with specific cultivar nutrient requirements seemed to determine the CS severity.