Evaluation of Salinity Tolerance of Tomato Cultivars, Breeding Lines and Their Hybrid Combinations under Greenhouse Conditions

Salt stress often causes adverse effects on growth, yield and quality of vegetable crops. Four commercial tomato cultivars ('Imperial', 'Pakmore VF', 'Queen' and 'Strain-B'), two salinity tolerant breeding lines (BL 1076 and BL 1239) and their fifteen hybrid combinations were used in this study to evaluate their salinity tolerance and select starting material for salinity tolerance breeding program in tomato. Four weeks old seedlings were transplanted in soil under greenhouse conditions. Six water salinity levels (1.2, 2.4, 4.8, 7.2, 9.6 and 12.0 dS m(-1)) were imposed through drip irrigation system. Average fruit weight, total yield, leaf concentrations of Na+, Cl-, Ca++ and K+ were measured. At a level of 12.0 dS m(-1), the reduction in yield and average fruit weight were more than 50% and 60% respectively for all genotypes, except for the two breeding lines BL 1076 and BL 1239. Increasing salinity levels led to raising Na++ and Cl- and lowering Ca++ and K+. Significant differences among genetic populations were found in all traits, suggesting they could be taken into account when selecting for salt tolerant tomato genotypes. The two cultivars; 'Pakmore VF' and 'Strain-B' reflected good performances for most traits under different salinity levels and could be selected as recurrent parents (female). The breeding line BL 1076 had the highest salinity tolerance for most traits and could be selected as donor (male) parent in breeding programs. These parents and hybrid combinations will be used in the breeding programs for salinity tolerance.