Three apple cultivars (McIntosh, Delicious and Empire) were used in 19
89 to study seasonal fruit growth. Fruit fresh weight (FW), dry weight
(DW), dry matter concentration (DMC) and relative growth rate (RGR) w
ere regressed against days after full bloom (DAFB) while partitioning
the fruit growth curve into either two or three linear phases. Linear
phases in fruit DW and FW development were evident throughout most of
the growing season. However, cultivars differed in seasonal FW and DW
accumulation totals and daily rates. Fruit RGR gradually declined unti
l 75-80 DAFB, when it reached a low and constant rate until harvest. T
he DMC of fruitlets at about 30-35 DAFB was about half that at full bl
oom. After an additional 20-30 d during which DMC increased, fruits ma
intained a relatively stable DMC level to the end of the season.