Degreening, Softening and Chilling Sensitivity of Early Harvested ‘Zesy002’ Kiwifruit under Elevated Temperature Conditioning in a Controlled Atmosphere

Abstract

Commercially produced volumes of Actinidia chinensis var. chinensis ‘Zesy002’ (Zespri® SunGold Kiwifruit, Tauranga, New Zealand) are increasing rapidly. One approach to managing the harvest logistics is to start the harvest season earlier by harvesting fruit before they have fully degreened on the vine. However, there are risks: the fruit are chilling-sensitive and they may soften excessively while degreening at elevated temperatures off the vine. Degreening and softening were investigated for ‘Zesy002’ kiwifruit harvested before fully degreened, and then allowed to degreen for 2 or 4 weeks at 10 °C in air or in a controlled atmosphere (CA; 2% oxygen/2% carbon dioxide). Fruit were then stored in air or CA at 1 °C up to 16 weeks from harvest, after which they were assessed for chilling injury. The main findings were that holding fruit in CA rather than air at 10 °C caused slower degreening, delayed the change to rapid softening, and also delayed the loss of chilling sensitivity. It is concluded that if ‘Zesy002’ fruit are to be degreened in CA, then either a longer conditioning period in CA, or more advanced fruit, should be used.

Keywords

• <i>Actinidia</i>
• fruit
• flesh color
• firmness
• disorder
• chilling injury