ISHS Acta Horticulturae 175: Symposium on Physiology of Productivity of Subtropical and Tropical Tree Fruits
OPTIMAL LEAF:FRUIT RATIOS FOR FRUIT GROWTH IN KIWIFRUIT |
| Authors: | W.P. Snelgar, T.G. Thorp, K.J. Patterson |
| Abstract:
The effects of different leaf:fruit (L:F) ratios on fruit weight in Actinidia deliciosa cv. 'Hayward' growing in Te Puke, New Zealand were investigated during three growing seasons. Individual laterals (current season's fruit-bearing growth which arises from long canes laid down the previous season) or whole cane and lateral systems were used as experimental units. Treatments were imposed approximately two to three weeks after flowering and were maintained until harvest. On intact laterals, L:F ratios ranging from 1:1 to 5:1 had no significant effect on fruit weight at harvest. An experiment using totally defoliated canes (L:F of 0:1) showed that mean fruit weights were not consistently affected by defoliation, even when some fruits were over two metres from the nearest leaf. In contrast, fruit weights on girdled laterals increased with increasing L:F over the range 1:1 to 3:1 at a rate of approximately 30 g per L:F unit. Ratios of 2:1 resulted in fruit of similar weight to those from intact laterals. During the 1983 season crop loads and leaf numbers on 16 whole vines were adjusted by removing either fruit or leaves so that L:F ratios ranged from 2.5:1 to 5.5:1. On these vines mean fruit weight increased with increasing L:F (Weight (g) = 67 + 6.9 L:F). However this increase in the weight of individual fruits was not sufficient to compensate for the corresponding reduction in fruit numbers, thus total vine yield decreased with increasing L:F ratio. The implications of these results are discussed in terms of the physiology and management of kiwifruit vines. | |
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