Evaluation of pre-harvest foliar calcium applications on 'Fuji' apple fruit quality during cold storage

Abstract

In this study, calcium chloride (CaCl2) and two organic calcium compounds including Calcicat® and Folical® and water (as control) were applied at four different spray programs (All-season, Early, Mid and Late season spray) at the Abhar region in Iran during 2012 and compared. 6-year-old 'Standard Fuji' trees grafted on 'MM106' rootstock were used in this study. All spray programs involved 6 biweekly sprays. Fruits harvested at commercial maturity stage and stored at commercial cold storage at 0°C and RH 95%. Overall, all treated fruits received Late season CaCl2 had higher Ca content, lower K/Ca and (K+Mg)/Ca ratios, and fruits treated with Folical Mid season had lower Ca, higher K/Ca and (K+Mg)/Ca ratios. Yield efficiency (No. of fruits per cm2 trunk cross-sectional area (TCSA)) and fresh fruit weight was affected by preharvest treatments. Ca application resulted in reduced yield efficiency. SSC, TA and flesh firmness were affected by Ca application and spray programs at harvest and during 3 and 6 months storage. Control fruits in All-season spray program had highest content of SSC and fruits received CaCl2 Early had lowest SSC at harvest. Folical All-season resulted in fruits with higher acidity than its control. Fruits treated with Calcicat Early had lower acidity. During 3 and 6 months cold storage, SSC increased and TA decreased. During 6 months storage, Calcicat All-season had higher SSC. Fruits received early season CaCl2 had more acidity than other treatments. All-season spray of Calcicat resulted in fruits with higher firmness than other treatments. The flesh firmness during 3 and 6 months storage decreased. According to the obtained data this reduction had not specific trend among treatments.