PHYSICOMECHANICAL PROPERTIES OF GALA APPLES AND STEM-END SPLITTING ASINFLUENCED BY ORCHARD MANAGEMENT-PRACTICES AND HARVEST DATE

The influences of irrigation (frequent versus none), crop density (hig h versus low), and nitrogen (urea fertilizer versus none) on the physi co-mechanical properties of mature ''Gala'' apples were evaluate:d. Bo th frequent irrigation and a low crop density increased fruit size. Fr uits from non-irrigated trees were firmer and had higher soluble solid s concentration (SSC) compared with fruits from frequently irrigated t rees. Similarly, the fruits from trees with a low density of crop were firmer and had higher soluble solids concentration (SSC) compared wit h the fruits from trees with a high crop density. Nitrogen application had no significant effect on any measured fruit property, and both sk in strength and stem adhesion force were not affected by orchard treat ments. Analyses of fruit attributes at three harvest dates correspondi ng to early, mid, and late harvest showed that fruit mass and SSC incr eased towards late harvest, while flesh firmness and skin strength dec reased with advancing fruit maturity. The stem adhesion force changed little during the harvest period. Comparison of fruits with stem-end s plits and good fruits showed that split fruit had a lower firmness, in dicating that split fruits were physiologically more advanced in matur ity and ripening. (C) 1997 Silsoe Research Institute.