INFLUENCE OF SALINITY ON THE INCIDENCE OF THE PHYSIOLOGICAL DISORDER INTERNAL FRUIT ROT IN HYDROPONICALLY-GROWN EGGPLANTS

Salinity aggravated the incidence of the calcium-related physiological disorder internal fruit rot in eggplants grown in recirculating nutri ent solution. Affected fruits contained less calcium than normal fruit s. Different ionic composition of nutrient solutions with high total s alt concentration had no specific effect on the occurrence of internal fruit rot or on fruit calcium concentration, when electrical conducti vities were identical. The calcium concentration of leaves was not red uced by salinity, even when the calcium level of the fruits was marked ly depressed and most of them showed internal fruit rot. The K, Mg, N, P, Na, and Cl determinations did not reveal any significant differenc es between fruits with and without internal fruit rot, but the Mg conc entrations were slightly higher in the diseased fruits. Salinity incre ased starch and sucrose concentration and reduced glucose and fructose levels in fruits collected at the first harvest. At that time, the in cidence of internal fruit rot in the salt treated plants was pronounce d.