Growth, yield and fruit quality of Mexican tomato landraces in response to salt stress

Abstract

The Mexican tomato landraces ‘Campeche’, ‘Oaxaca’, ‘Puebla’, and ‘Veracruz’, and the commercial hybrid ‘Vengador’ were evaluated in response to four levels of NaCl (0, 30, 60 and 90 mM) applied through the nutrient solution in a hydroponic system under greenhouse conditions. Yield and dry biomass weight of roots, stems and leaves were reduced by increasing salinity stress, while fruit quality characteristics were improved, with the magnitude of the changes being genotype-dependent. The landrace ‘Veracruz’ produced the lowest yield, 1.06 t ha-1 under control conditions and 0.59 t ha-1 when treated with 90 mM NaCl, amounting to a 44% reduction that was, however, the lowest yield decrease among all genotypes tested. Paradoxically, ‘Veracruz’ was the only landrace displaying a reduction in the root/shoot ratio when exposed to high salinity, indicating more sensitivity to salinity as compared to the other landraces and the hybrid tested. ‘Campeche’ performed the poorest in response to salinity with the most pronounced yield reductions, recording 71.1%, 80.1% and 89.6% yield decreases when comparing plants exposed to 30, 60 and 90 mM to the control, respectively. Although at each salinity level the ‘Veracruz’ fruits showed the highest °Brix value as compared to the other landraces and the hybrid, ‘Oaxaca’ and ‘Puebla’ fruits had a greater increase in °Brix between the control and 90 mM NaCl (109.2% and 110.4%, respectively). With 90 mM NaCl, ‘Oaxaca’ fruits also registered the highest decrease in pH (6.1%) and the highest increase in total soluble sugars (106.7%) with respect to the control.