SPATIAL-ANALYSIS OF THE CANOPY OF KIWIFRUIT VINES AS IT RELATES TO THE PHYSICAL, CHEMICAL AND POSTHARVEST ATTRIBUTES OF THE FRUIT

The position of individual fruit on kiwifruit vines (Actinidia deliciosa var. deliciosa) grown on a horizontal trellis (pergola) and on a T-bar trellis was determined using a theodolite. The physical, chemical, and postharvest attributes of the fruit were related to their position on the vine during development. Fruit from the pergola vines were more numerous, of lesser weight, with lower concentrations of most mineral nutrients, but greater concentrations of soluble solids, and similar flesh firmness after 12 weeks of storage at 0 °C, than fruit from the T-bar vines. The position on the vine accounted for most of the variation in the attributes of the fruit. Differences between fruit on a single lateral accounted for 43-56% of the variation. Variation between vines was relatively small (<4% of the total variance). The heavier fruit were located at the apical ends of the laterals, while greater concentrations of soluble solids were associated with fruit located closer to the cordon. The larger fruit from the pergola vines developed from the early opening flowers. A similar relationship existed initially for the T-bar vines, but a reduction in growth of fruit from the early opening flowers 8 weeks after anthesis resulted in a more even distribution of fruit size at harvest. The strongest relationship between mineral composition and postharvest attributes of the fruit was with soluble solids concentration (29-46% of the variance). The relationship with flesh firmness was weak (r = - 0-14 to -0-32). Individual elements could not be considered in isolation but rather in groups of elements. Nitrogen was grouped strongly with phosphorus, sulphur, potassium, and copper, while calcium was linked with a second group which included manganese and zinc. These two groups were negatively related to one another. The greatest proportion of fruit with superior characteristics was located in the denser parts of the canopy. Fruit with less desirable attributes were from the extremities of the canopy where the leaf area Index was low. © 1994 Annals of Botany Company.