Effects of different harvesting dates on fruit quality and storage tolerance of five kiwifruit varieties

【Objective】As a typical climacteric fruit, the preharvest physiological maturity of kiwifruit critically determines its postharvest storage performance, sensory characteristics and nutritional quality. Assessing maturity based solely on fruit size, shape, or skin color at harvest is often unreliable, and the optimal harvest timing varies considerably among kiwifruit cultivars. Both premature and delayed harvesting negatively affect fruit quality and storage performance. Accordingly, precise harvest scheduling is essential for guaranteeing high fruit quality. This study aimed to identify the optimal harvest windows and assess the variations in fruit quality among five major kiwifruit cultivars cultivated in the Xiangxi region of Hunan Province, China, so as to provide a scientific foundation for developing region-specific standardized harvest protocols.【Methods】Fruits were harvested at six developmental stages, which corresponded to 108, 118, 128, 138, 148, and 158 days after full bloom (DAFB).A comprehensive range of physicochemical and storage-related attributes was analyzed, including fruit weight, longitudinal diameter, transverse diameter, exocarp firmness, and pulp firmness (measured at harvest and after soften-ing), soluble solids content (SSC), dry matter content (DMC), titratable acidity (TA), soluble sugar content, ascorbic acid (AsA) content, and sugar-acid ratio. Additionally, postharvest performance was evaluated during 35 days of storage at room temperature by tracking weight loss, softening rate, and decay incidence. Two-way ANOVA and principal component analysis (PCA) were used to analyze and integrate these multi-dimensional data, and comprehensive scores were calculated to determine the optimal harvest window for each cultivar.【Results】Two-way ANOVA showed that both cultivar and harvest date, as well as their interaction, had highly significant effects (P＜0.01) on soluble solids content (SSC), titratable acidity (TA), and fruit firmness. Principal component analysis (PCA) extracted three principal components, which together accounted for 85.83% of the total cumulative variance. Comprehensive evaluation identified distinct optimal harvest windows: 148 days after full bloom (DAFB) was determined to be the ideal harvest period for Jinhong 1, Hongyang, and Huangxin B (A. chinensis), while Huangxin A (A. chinensis) and Miliang 1 reached peak quality at 158 DAFB. We observed significant differences in storability across these cultivars. Jinhong 1 and Hongyang are classified as rapid- ripening, highly perishable cultivars. When harvested at or after stage Ⅳ, their fruit decay rate exceeded 70% after only 14 days of storage. In contrast, Huangxin A and Huangxin B showed low, stable weight loss rates. After 35 days of storage, their decay rates ranged between 80% and 90%, so they are classified as slow-ripening, storable cultivars. For Miliang 1, although harvesting at early stages resulted in relatively high weight loss, its storability was significantly improved when harvested in the mid-to-late season. 【Conclusion】Optimal harvest windows vary considerably among these five kiwifruit cultivars. Jinhong 1 and Hongyang are rapid-ripening cultivars that require prompt marketing after harvest. In contrast, the Huangxin series and Miliang 1 feature slower ripening and superior storability, providing greater commercial adaptability for the kiwifruit industry.