Evaluation of Vitamins and Glycoalkaloids in Potato Genotypes Grown Under Organic and Conventional Farming Systems

Potato tubers provide people not only with carbohydrates but also with other essential compounds for human health. Several investigations have compared the quality of crops grown under organic and conventional farming systems. The aim of the present study was to evaluate the concentrations of vitamins C, B₁ and B₂ as well as glycoalkaloids (α-solanine and α-chaconine) in potato tubers of different genotypes and to estimate the farming system (conventional and organic) impact on the content of these compounds. Twenty potato genotypes were grown under organic and conventional farming systems in Priekuli (Latvia) during 2010 and 2011. The concentrations of vitamins C, B₁ and B₂ as well as glycoalkaloids (α-solanine and α-chaconine) were significantly influenced by the potato genotype. The vitamin B₁ concentration of potato genotypes grown in the organic field exceeded that of potato genotypes grown in the conventional field. A significant negative correlation was found between the vitamin C concentration and tuber yield only in the conventional field. No significant correlations were found between the other potato characteristics, such as starch content, tuber taste after boiling and glycoalkaloids, vitamins C, B₁ and B₂. The high broad-sense heritability for all tested traits (vitamin C 93%, vitamin B₁ 92%, α-solanine 88%, α-chaconine 84% and vitamin B₂ 70%) demonstrated that the high genetic diversity in the potato genotype population accounted for the phenotypic expression. The present study suggested that the breeding of new potato varieties with improved nutritional quality can be launched, and that the varieties that will be developed can be produced in an environmentally friendly way.