Breeding Tomatoes for Salt Tolerance: Variations in Ion Concentrations Associated with Response to Salinity

Abstract

Accessions of four tomato species, Lycopersicon esculentum Mill. (Le), L. pennellii (Corr.) O'Arey (Lpen), L. cheesmanii Riley (Lc), and L. peruvianum (L.) Mill., (Lper), and interspecific populations were irrigated with saline water under field conditions and concentrations of Na, K, Cl, Ca, and Mg in leaves and stems were determined. Potassium: sodium ratios in leaves and stems of salt-tolerant genotypes were higher under salinity and were moderately changed by salinity compared to the sensitive genotypes. In the tolerant wild accessions and F 1 (Le × Lpen), Cl concentrations in leaves and the ratio between Cl in leaves to Cl in stems were lower than in the sensitive Le cultivar. Regulation of the K: Na ratio was found in tolerant wild accessions and tolerant Le cultivars, while regulation of Cl concentration in leaves was found only in the wild germplasm. The effects of ion concentrations on dry matter of interspecific segregating populations, F 2 (Le × Lpen) and BC 1 (Le × (Le × Lpen)), were studied by regression analyses. Dry matter was positively correlated with the K: Na ratio in stems and negatively correlated with the Cl concentrations in leaves and stems, thus confirming the results obtained by comparison between the tolerant and sensitive accessions.