Effect of overhead shading on yield and fruit quality of kiwifruit (Actinidia deliciosa)

Summary

Kiwifruit vines (cv. Hayward) were shaded from early spring until fruit harvest at levels of 100% (control), 70% or 45% full sun. Although shoot growth during the early part of the season was not significantly affected by the shading, the percentage bud burst was reduced and the time of full bloom appeared to be slightly delayed. The mean fresh weight of individual fruits was significantly reduced by shading, and fruit on shaded vines reached commercial harvest maturity of 6.2% soluble solids two to three days later than those on unshaded vines. During cool storage, fruit from vines grown under 45% full sun were slightly but consistently less firm and had lower soluble solids concentrations than unshaded fruit. No differences in the starch or total sugar contents were found between shaded or unshaded fruit, either at harvest or after cool storage. Shading vines did not affect either the colour (HunterLab values) or the chlorophyll concentration of fruit. Possible implications of these results for commercial orchards are discussed.