Yield and fruit quality of sweet pepper in response to fertilisation with Ca2+ and K+

The influence of Ca2+ and K+ levels on fruit yield and quality of sweet pepper (Capsicum annuum L. cv. Orlando) plants under hydroponic culture has been investigated. The treatments consisted of three concentrations of Ca2+ (1.5, 4 and 8 mmol L-1) and K+ (2.5, 7 and 12 mmol L-1) that were imposed separately. Fruit yield parameters and different fruit quality parameters, as well as dry matter production and mineral composition in individual parts of the plant, were determined. The increase of Ca2+ in the root medium increased the marketable yield from 1.67 to 2.38 kg plant(-1), mainly due to an increase in the number of fruits per plant, while higher K+ levels decreased marketable yield from 2.2 to 1.66 kg plant(-1), due to decreases in the number of fruits per plant and the mean fruit weight. With respect to fruit quality, fruit shape index and, therefore, pepper fruit appearance improved with Ca2+ addition to the root medium. Fertilisation with K+ increased fruit acidity and decreased maturity index, which could improve fruit storability. Low Ca2+ or high K+ levels reduced both root and shoot dry matter. Therefore, an adequate management of fertilisation with Ca2+ and K+ could improve the yield and fruit quality of pepper grown in soilless culture.