Salinity duration and concentration affect fruit yield and quality, and growth and mineral composition of melon plants grown in perlite

The shortage of good quality water in semiarid zones necessitates the use o f saline water for irrigation. In order to simulate the usage of brackish i rrigation water in greenhouse melon (Cucumis melo L. cv. Galia) culture in perlite, plants were supplied with nutrient solutions containing 0 (control ), 20, 40, and 60 mM NaCl applied at four different times. Treatments were applied during early vegetative growth [14 days after transplanting (DAT)], beginning of flowering (37 DAT), beginning of fruit set (56 DAT), and begi nning of fruit ripening (71 DAT). All vegetative and fruit yield parameters were significantly reduced when salinization was started 14 DAT. This inhi bitory effect of salinity was progressively lessened when salinity was impo sed at later dates. This suggests that the response of melons to salinity d epends on the duration of exposure to saline water. Salinity treatments inc reased fruit reducing sugars, acidity, and total soluble solids. Fruit yiel d reduction at each salinization time was correlated with salinity levels, but there was some evidence of a nutrient imbalance, since leaf concentrati ons of N-NO3, and especially K, were low at higher salinities. These result s indicate that brackish waters can be used for growing melon with minimum yield losses if concentration and duration of exposure are carefully monito red.