Quality of 'Hayward' Kiwifruit in Prolonged Cold Storage as Affected by the Stage of Maturity at Harvest

The effect of 'Hayward' kiwifruit maturity at harvest on fruit quality during long-term storage at -0.5 & DEG;C was evaluated by harvesting the fruit several times, at different stages of maturity. The progress of maturation on the vine was monitored weekly from 136 DAFB (days after full bloom). Fruit were harvested for storage at three points and stored for 3-6 months in regular air (RA), or for 6-10 months in a controlled atmosphere (CA), with or without prestorage exposure to 1-methylcyclopropene (1-MCP). The softening rate under both storage regimes decreased with the advance in fruit maturation on the vine, as indicated by increasing soluble solids content (SSC), and declining firmness. As a result, the fruit from the first harvest (152 DAFB), which were the firmest at harvest, were the softest at the end of both storage regimes. Delaying harvest also decelerated the decline in acidity during storage, so that fruit picked last maintained the highest titratable acidity (TA) upon removal from storage. The overall fruit quality after shelf life, following prolonged storage in either RA or CA, was improved by delaying harvest to late November (ca. 200 DAFB). The harvest criteria for fruit with the best storage potential were dry matter (DM) > 17%, SSC > 7%, TA 2.0-2.6%, with more than 40% of the DM non soluble. From a commercial aspect the rule should therefore be 'Last in, last out' (LILO).</p>