Foliar applications of calcium and potassium increase cracking resistance and enhance fruit quality in sweet cherries

Sweet cherry production represents a competitive sector with important economic prospects but faces many challenges. Rain-induced cracking stands out as a particular issue, as it has been linked to yield losses of up to 90%. To address this concern and meet consumer demand, foliar treatments, involving a mixture of commercial products rich in calcium and potassium salts, have been tested in sweet cherry commercial orchards. This study was a randomized block experiment consisting of three blocks (ten plants each), five of which were treated and five were controls. The treatments were applied in addition to the standard cultivation practice throughout the season. Observations were made on the SPAD index and shoot elongation, and in post-harvest, cherries were analyzed for qualitative characteristics (skin color, caliber, firmness, total soluble content, titratable acidity and cracking index) and nutraceutical parameters (total anthocyanin content, total phenols content and antioxidant activity). Results indicate that foliar salt application can facilitate the maturation process, indicated by a higher soluble solid content (TSS), softening, and darker pigmentation in treated fruits. The applied formulations also provided increased shoot growth and enhanced SPAD index. Furthermore, the treated fruits exhibited a significantly lower incidence of cracking compared to the control treatment and showed improved nutraceutical properties