Genetic analysis of sodium, potassium and chloride ion content in Lycopersicon

Plants of the salt-sensitive L. esculentum, the halophytic wild species L. pennellii, their F₁ hybrids and the interspecific F₂ generation were grown in Hoagland's liquid culture containing 100 mM NaCl and 6 mM K⁺. Analysis of the Na⁺, Cl^- and K⁺ ions contents of the leaves showed, as observed also in previous studies, that the cultivated parent accumlated more K⁺ and less Na⁺ than the wild parent. A total of 117 F₂ plants were assayed for 15 electrophoretically detectable isozyme markers which map to nine of the twelve tomato chromosomes. Four loci, all with a similar quantitative effect on Na⁺ and Cl^- uptake, were identified by virtue of their linkage to isozyme markers. Two other loci were found to affect K⁺ uptake. This study demonstrates the potential value of using genetic markers in order to gain a better understanding of the genetic basis of quantitative traits associated with the response of plants to salinity stress.