SALINITY EFFECTS ON SOME POSTHARVEST QUALITY FACTORS IN A COMMERCIAL TOMATO HYBRID

The commercial F1 tomato hybrid (Lycopersicon esculentum L. Mill) cv. Radja (GC-793) was cultivated with low (control), moderate (70 mM NaCl ) and high (140 mM) salinities under greenhouse conditions for 14 week s. The effects of different salinity levels on fruit weight and major chemical components determining fruit quality were assessed. Red ripe fruits were harvested to determine fruit weight, size and composition. The water content and mineral composition were determined in whole fr uits; the carbohydrate, organic acid and soluble protein contents were analyzed in pericarp tissue. Moderate salinity reduced the fresh and dry fruit weights by only 10 and 13%, respectively, while high salinit y reduced them by 40 and 33% compared with control fruits. The water c ontent was not significantly affected by salinity. Thus, fruit weight does not seem to be limited by the water supply under these conditions . The amount of Naf significantly increased only at high salinity, whi le Ca2+ and Mg2+ contents were not affected. K+ content, which represe nts more than 70% of the mineral composition, tends to increase with s alinity. The citric acid content slightly increased at moderate salini ty, while both citric and malic acids contents were reduced at high sa linity, increasing the citric/malic ratio. The pH values were always a bout 4. The low content in soluble proteins was reduced by high salini ty, while moderate salinity increased it. In pericarp tissue of modera tely treated fruits, the fructose and glucose contents were three time s and twice as high as control and highly salinized-ones. Starch, sucr ose and myo-inositol also accumulated under salinity. Hexoses and star ch accounted for 20, 66 and 42% of the pericarp dry matter in control, moderate and highly salinized fruits, respectively.