UNDERSTANDING POSTHARVEST QUALITY OF KIWIFRUIT IN RELATION TO SHOOT AND CANE VIGOR

Abstract

Global kiwifruit production has expanded considerably. Over-softening and a low soluble solids concentration of kiwifruit after storage are the main factors associated with market satisfaction. Variability between kiwifruit batches, which is associated with season, orchard, pre- and postharvest practices, can result in fruit with unpredictable postharvest quality. The origin of fruit from different locations on a vine was used to explain the variation at harvest and postharvest quality. Fruit selected from different associations between shoot and cane vigor (evaluated by diameter) from vines of three orchards with demonstrated that fruit growing on terminated shoots was dominant. In addition, dry matter concentration and ripe soluble solids concentration were not affected by cane or shoot diameter. Further, fruit size was positively related to terminated shoot length and firmer fruit developed on non-terminated shoots compared with terminated shoots when assessed after ripening. These data were validated during the following year using data collected from eight orchards. Here, a comparison of fruit from non-terminated shoots with a small diameter (8.1-9.6 mm) growing on medium-diameter canes (22.4-24.5 mm) and from terminated shoots with a medium diameter (10.7-11.7 mm) growing on small-diameter canes (15.2-15.9 mm) demonstrated that terminated shoots produced softer fruit, and the nitrogen concentration in the pulp of these kiwifruits at harvest was negatively correlated with fruit firmness measured after 75 days at 0°C + 4 days at 20°C.