The influences of ABG-3168 (ReTain), GA3, calcium and boron applications,
at about four weeks before commercial harvest date, on maturity, ripening, pre-
harvest drop and storability of Anna apple fruits (Malus demestica Borkh) were
investigated during the two successive seasons of 2002 and 2003. The results
showed that most maturity/ripening related fruit characteristics were significantly
influenced by the tested treatments. ABG. ABG-treated fruits, at 250 and 500 ppm,
were approximately one (Kg) firmer than non-treated ones on a given sampling date
during both pre and post-harvest phases. Red color formation was inhibited,
conversion of starch into sugar was less advanced and acidity was higher in this fruit
compared with the control, indicating that maturation and ripening had been
suppressed. ABG-treated fruits also contained a significant higher TSS concentration,
only after shelf life, than the other treatments. Both the rate and the onset of red color
accumulation were clearly stimulated and advanced (about one week) by boron
application at both 50 and 100 ppm without hastening fruit ripening compared with the
control. Pre-harvest fruit drop was effectively controlled by ABG application at both
250 and 500 ppm. While, CaCI2 application at 2% greatly increased pre-harvest drop
and caused leaf scorching. Gibberellic acid application, especially at 500 ppm,
significantly increased fruit diameter in contrast to ABG one, especially at 500 ppm,
which slightly decreased it compared with the control. Fruit weight was not
significantly influenced by any of the applied treatments. The occurrence of browning
was greatly decreased during storage and was completely eliminated during one
week of shelf life by ABG application. However, the other treatments either had no
significant effect or even increased the occurrence of browning. Our results herein
pointed to ABG pre-harvest treatment as the best one to delay maturity and ripening
and to improve the storability of Anna apple fruits under the Egyptian conditions. The
efficacy of ABG treatment at the low concentration (250 ppm) was equal or even
better than the high concentration (500 ppm). Also, the low concentration of ABG had
less negative impact on fruit red colour formation and diameter.