Apples have many desirable attributes but their ability to withstand long-term cold storage is probably their most important commercial one.
For this reason, growers want a quick assessment of the storage potential of any new cultivar. Fruit quality can be assessed in various ways but changes in firmness and titratable acidity are considered especially important for apples.
In the research described here, fruits of 20 cultivars were stored for up to 10 months at 0.5 degsC and for 40 days at 20 degsC. The weight, firmness and acidity of sample fruit were assessed at the start of storage and again at intervals thereafter. In general, fruit lost weight more rapidly at 20 degsC than at 0.5 degsC.
Although minimum firmness varied between cultivars it was unaffected by the storage conditions as the minimum firmness of each cultivar was the same after 20 days at 20 degsC as after 180 days at 0.5 degsC.
Initial acidity differed greatly between cultivars as did minimum acidity but the rate of loss of acidity at 0.5 degsC was always 3.7 times slower than at 20 degsC. Hence, the storage performance of a cultivar after just 20 days at 20 degsC could be used to give an indication of its likely long-term performance at 0.5 degsC.
Storability in Cold Temperatures can be Evaluated based on Changes in Fruit Quality in Apple Genotypes under Shelf Life Conditions by Iwanami, Moriya, Kotoda, Takahashi and Abe (2008). HortScience 43 (3): 655-660.Members of ISHS can view HortScience at the website, www.ishs.org.