Effect of irrigation water salinity on yield and fruit quality of tomato

A field experiment was conducted in the middle area of the Nile Delta, Egypt, to study the effect of different salinities of irrigation water (0.55, 4 or 6 dS m(-1)) on yield, yield components and fruit quality of 27 tomato genotypes. The results showed that salinity at 4 and 6 dS m(-1) decreased total yield, marketable yield, number of fruits and average fruit weight in all genotypes studied. Cultivars "La Laguna" followed by "RETBA" (both known to be salt tolerant) showed the least reduction in yield under salinity treatments. Cultivars "Floradade" and "Edkawy" and hybrid "Baraka" also showed low yield reductions. This implies that such genotypes were relatively salt tolerant. It was also observed that the reduction in yield in the salt tolerant genotypes, was mainly due to the reduction in fruit weight rather than fruit number. Cultivar "Super Strain B" showed the highest reduction in yield. Hybrids "Early Rock", "Shiva (95558)", "Confidence" and "HZ 8704" as well as cultivar "Pacmour", showed severe yield reduction under salinity conditions particularly at 6 dS m(-1). This suggests that these genotypes were salt sensitive. However, irrigation with saline water up to 6 dS m(-1) increased fruit total soluble solids (TSS), vitamin C, and dry matter contents in all genotypes. Fruit acidity was also enhanced by salinity although 4 dS m(-1) level gave the most acid fruits. Salinity had no significant effect on fruit firmness and storage ability.