Relationships between blossom-end rot and water availability and Ca fertilization in bell pepper fruit production

Blossom end rot (BER) is one of the main physiological disorders in bell pepper fruit, reducing export and marketable yield during late spring and summer in Israel. BER occurrence has been related to calcium deficiency and water supply to the fruit. The objective of the present study was to explore management means to minimize this phenomenon. The effects of three irrigation frequencies (3,6 and 12 times a day) on greenhouse-grown bell pepper plants were studied in two years experiments. In the first year the irrigation treatments were combined with three Ca concentrations in the irrigation solution (50, 100 and 150 mg L-1). In the second year they were combined with three types of tuff of different particle diameters (0-2 mm (fine), 0-4 mm (medium) and 0-8 mm (coarse)). Increasing Ca concentration in the solution resulted in higher Ca content in pepper leaf and fruit. High irrigation frequency enhanced Ca concentration in leaf and fruit, especially of the low Ca treatment. Irrigation frequency and Ca concentration in the solution influenced the incidence of BER during the late springtime; the lowest BER incidence was obtained in the combination of the most frequent irrigation with the highest solution Ca concentration. Ca content in plant organs increased and the BER decreased as the growth medium particle diameter decreased. The greatest effect of high irrigation frequency on reducing BER was obtained in coarse particle substrate. High irrigation frequency minimized the amplitude in the water content of the growth medium. This is probably the cause of the enhanced Ca uptake and reduction in the BER occurrence by high irrigation frequency.