Phosphorus (P) is essential to increase tuber yield and nutritional quality of potato tubers. However, it is unclear whether the influence of P fertilization on quality of tubers produced can vary depending on the cultivar and P availability in soil. This study evaluated the effect of P fertilization on the quality and nutritional composition of marketable tubers of potato cultivars. Experiments in soils with low, medium and high P availability were conducted in a randomized block design, with four replications. Treatments consisted of a 2×5 factorial arrangement of two potato cultivars (Agata and Mondial) and five P2O5 rates (0, 125, 250, 500, and 1,000 kg ha–1). Phosphorus fertilization increased the contents of P and starch, the size and yield of marketable tubers, with more expressive response to higher P rates in the soils with low and medium P availability. The Mondial cultivar had the highest yield, due to a greater tuber weight and greater increases in this characteristic in response to P fertilization. The Mondial cultivar produced tubers with firmer pulp, with higher dry matter percentage and higher contents of Ca, Cu, and Zn than Agata. In the soil with low P availability, P fertilization reduced Zn content, but, in general, had little influence on the nutritional composition of potato tubers.
Solanum tuberosum ; phosphorus; tuber size; starch; protein; mineral concentration