The objective this work was to evaluate the effects of sources of calcium (Ca), sprayed at preharvest, on bitter pit control and physico-chemical quality of 'Catarina' apples. The experiments were conducted during three seasons (2004/2005, 2005/2006 and 2006/2007) in a commercial orchard, in São Joaquim, State of Santa Catarina, Southern Brazil. The experiment followed the randomized block design, with four repetitions. The sources of Ca tested were CaCl2, Calboron, Sett, Aminolom Floración, Max Fruit, S-CaB, Cal Super, Wuxal Cálcio, Orgasol Ca, CalSOL 15, Coda-Ca-L and CodaSal-Plus 2000. The spraying of treatments started at the phenological stage J (green fruit) and finished 30 days before fruit harvest. The incidence and severity of bitter pit was assessed at harvest (in 2005/2006 and 2006/2007), and after three (in 2005/2006) and five (in 2006/2007) months of cold storage. The control treatment (without Ca) exhibited incidences of bitter pit of 24% and 46% in 2005/2006 and 2006/2007, respectively. Only in 2004/2005, the treatments CaCl2, Calboron + CaCl2, Sett, Calboron and S-CaB increased the Ca content in the fruits. Preharvest sprayings with CaCl2, Calboron and Sett in 2005/2006, and with CaCl2 and CalSOL 15 (10 and 15 sprayings) in 2006/2007, reduced the incidence of bitter pit, without significantly changing the fruit contents of Ca, N and K in comparison to the control. The results show that the source of Ca tested did not increase consistently the Ca content in the fruit and had small efficiency to control bitter pit in 'Catarina' apples, with a slightly higher efficiency for calcium chloride to control the disorder. In all three seasons, the preharvest spraying with different sources of Ca had no significant effect on yield, fruit weight and physico-chemical quality of the fruits at harvest.
Malus domestica Borkh; calcium; fruit; physiological disorder
