Soil and foliar application of potassium enhances fruit yield and quality of tomato under salinity

Potassium plays a key role in the survival of plants under saline conditions in mitigating the adverse effects of sodium. The effect of application of potassium to soil (0, 3.3, and 6.6 mmol/kg) and leaves (4.5 and 9 mM) on tomato yield and quality under 3 salinity treatments (0, 7.5, and 15 dS m-1), using 2 salt-tolerant (Indent-1 and Nagina) and 2 salt-sensitive (Peto-86 and Red Ball) genotypes, was studied in a pot experiment. Salinity decreased growth and yield of all genotypes; however, salt-tolerant genotypes maintained better growth and produced higher yield than the salt-sensitive genotypes across all salinity levels. Potassium application positively affected plant growth and yield, especially in salt-tolerant genotypes. Fruit quality characteristics (total soluble solids, titratable acidity, pH, dry matter %) were significantly improved by increasing salinity, except for fruit size. Soil and foliar K had nonsignificant differences between them; however, there were significant effects on the fruit quality, as all characteristics increased at higher K concentrations under salinity stress. It was concluded that the application of potassium increases yield and quality of tomato fruits in saline soil, and it could be used as an effective practice to produce even a salt-sensitive species like tomato under saline conditions.