Calcium Chloride and Putrescine Applied at Three Fruit Development Stages Improve the Quality of “Spring Crest” Peaches

Peach is a widely cultivated and consumed fruit; however, its yield improvement remains limited, and its shelf life is short due to its climacteric nature. Preharvest applications of putrescine (PUT) and calcium chloride (CaCl₂) are not widely practiced for improving fruit quality. The study aimed to assess the individual and combined effects of PUT and CaCl₂ sprays on “Spring Crest” peach quality to improve fruit development and reduce postharvest losses. Foliar applications of PUT (2 mM) and CaCl₂ (1%), applied alone or in combination, were tested at key stages of fruit development on eight-year-old peach trees in Swat, Pakistan. After harvest, peach fruits were stored under ambient conditions, and their physical and biochemical quality was evaluated over 12 days. Results demonstrated that the combined treatment (PUT + CaCl₂) significantly enhanced fruit weight, size, and pulp-to-stone ratio at harvest compared to the control. During storage, the combined treatment markedly reduced weight loss, maintained superior firmness, and suppressed ethylene biosynthesis. Additionally, fruits receiving the combined application retained higher titratable acidity and ascorbic acid content, while exhibiting slower sugar accumulation and more stable color parameters. These findings suggest that the combined preharvest application of CaCl₂ and PUT represents a promising, safe, and practical strategy to mitigate postharvest losses.