Differential response of potatoes (Solanum tuberosum L.) to salinity in an arid environment and field performance of the seed tubers grown with fresh water in the following season

Ten potato varieties, commonly grown in the Mediterranean region, were grown on sandy soil in an arid desert area of Israel. The potatoes were drip-irrigated with three water sources: fresh water (control – ENV1), saline water from a local well (intermediate salinity – ENV2) and the local well water enriched with NaCl (high salinity – ENV3). The average salinity levels expressed as the electrical conductivity (EC) measured in the soil extracts from the root zone were 2.35, 5.1 and 8.5 dS m−1 for the ENV1, ENV2 and ENV3 treatments, respectively. Salinity stress decreased fresh tuber yields, increased tuber dry matter and soluble solids, increased tuber electrolyte content and lowered osmotic potential (OP) of the tuber sap in all varieties. ANOVA and Fisherʹs LSD pair-comparisons revealed highly significant differences among the varieties in all traits. Correlation analyses showed negative associations between tuber yield and tuber traits (dry matter, DM; total soluble solids, TSS, EC and OP). Positive associations were found between tuber DM and TSS, EC and OP. There was no positive association between early maturation or yielding capacity and tolerance to salinity. Vivaldi, a high-yielding variety and Almera, a low-yielding variety were found significantly less susceptible to salinity than Mondial, a late-maturing and high-yielding variety, and Charlotte, an early-maturing and low-yielding variety. The significant differences in the response to salinity stress indicated genotypic variation in the response to salinity and support the potential of breeding for tolerance to salinity in potatoes.