Variation between apple fruits and its relation to keeping quality. III. Between-season variation in relation to seasonal climate.

Abstract

Studies were made of seasonal effects on ripening changes and disorder incidence in different varieties of apples in Tasmania for the 10-year period, 1933-1943. Most of the changes associated with ripening, namely, ground colour change, acid loss, starch conversion, soluble solids accumulation, softening, and respiration rise did not necessarily keep pace with each other and responded differently to seasonal variation, but there appeared to be a constant relation between firmness and acid level. In the final analysis, seasonal variation in the level of disorders was mainly related to differences in mean fruit size and when the size factor was held constant between seasons the differences remaining were relatively small. In the case of pit, some of these remaining differences could be accounted for by differences in relative maturity but in the case of breakdown, relative incidence between seasons was not related to relative maturity. There was an association of early blossoming with low incidence of pit and breakdown independent of later differences in seasonal climate. The results support the theory that low temperatures in the months prior to harvest increased susceptibility to breakdown.