Blossom-end rot: A calcium deficiency

Blossom-end rot (BER) is a common physiological disorder that occurs on the fruit of tomato (Lycopersicon esculentum Mill.), pepper (Capsicum annuum L.), eggplant (Solanum melongena L.), and watermelon [Citrullus lanatus (Thunb.) Matsun & Nakai]. BER may occur in all the tomato-producing areas of the world and has been shown to create losses up to 50%. BER is related to many factors including: high salinity, high magnesium (Mg), ammonium (NH4), and/or potassium (K) concentration, inadequate xylem tissue development, accelerated growth rate, unfavorable moisture relationships (high, low, or fluctuating), low soluble soil calcium (Ca), high temperature, and high and low transpiration, but the underlying cause of this disorder is an inadequate amount of Ca in the blossom-end of the fruit. Although it is widely accepted that a local Ca deficiency plays an important role in the induction of BER, there are also some claims that Ca deficiency is not the cause of BER as a critical level of Ca for BER induction has not been found. To prevent BER from occurring, an understanding of Ca in the soil, uptake and translocation of Ca, and the factors affecting these processes, is necessary.