Effects of Foliar Spraying of Potassium Sulfate on Fruit Growth and Quality of the Low-chill Early Ripening Peach ‘KU-PP1’

Abstract

The purpose of this study was to evaluate the effect of foliar spraying of Potassium Sulfate (K₂SO₄) on the fruit growth and quality of the low-chill early ripening peach ‘KU-PP1’. K₂SO₄ concentrations of 5 g·L^-1, 10 g·L^-1, and 15 g·L^-1 were sprayed at intervals of 30, 45, and 60 days after full bloom on the leaves of ‘KU-PP1’ peach; four branches per tree during the 2020 and 2021 seasons. The largest fruit size and diameter were observed in the 15 g·L^-1 K₂SO₄ treatments. Furthermore, the TSS were observed in the 15 and 10 g·L^-1 K₂SO₄ treatments, followed by the 5 g·L^-1 K₂SO₄ treatment, which was higher than the control during both years. K₂SO₄ treatment increased the photosynthesis rate, transpiration, and stomatal conductance of ‘KU-PP1’ peach compared to the control. The results also showed that the fruit color (L*, a*, and b*) was more enhanced in the 10 and 15 g·L^-1 K₂SO₄ treatments during both years. Based on our findings of positive correlations between K₂SO₄ and fruit quality attributes, we concluded that the 15 g·L^-1 K₂SO₄ treatment produced the superior results.