The effect of site conditions, variety and fertilization on the content of polyphenolsin potato tubers

Abstract

In precise field trials in the CR in the years 2004 and 2005 the effect of site conditions, yellow- and purple-fleshed varieties and fertilization on the content of total polyphenols (TP) in potato tubers was investigated. Comparing four localities, significantly highest TP content (by 5.7 to 13.4% higher than in other localities) was determined in the locality Stachy in both years, which we ascribe to apparently lower temperatures in the vegetation period in this locality of high altitude. In comparison to yellow flesh varieties, in the case of purple flesh Valfi variety TP content higher by 52 to 153% was recorded as the average of both years. As for the group of eight yellow flesh varieties, Karin variety had the highest TP content and showed a significant increase in comparison to Agria, Saturna and Asterix varieties by 67, 60 and 37%, respectively. TP content was not demonstrably affected by fertilization with mineral fertilizers, but we recorded a tendency to lesser TP content (by 3 to 9.9%) in the variant with higher potassium and magnesium fertilization (166 kg K/ha and 60 kg Mg/ha).