Preharvest calcium sprays were not always needed to improve quality of 'gala' apples in Brazil

Abstract

-Calcium sprays have normally improved both the quality and the storage life of apples throughout the world because Ca helps to prevent many fruit disorders and that taken up from the soil does not often reach the fruit in adequate amounts. Since the efficacy of Ca sprays varies according to soil, apple cultivar, and weather conditions, this study was carried out from 1998 to 2004, in the Southern of Brazil, in order to assess the effect of Ca sprays on the quality and storability of 'Gala' fruits. The experiment was set up in an orchard planted in 1988, on a density of 1234 trees/ha. Treatments consisted of 0, 4, 8, and 12 annual sprays of 0.5% CaCl 2 regularly distributed 30 days after petal fall until one week before harvest. Fruits of the same size and maturity level were annually analyzed at harvest and after five months of conventional cold storage (-1 o C and 90-95% of RH). In five out of six seasons, fruits from all treatments were free of any physiological disorder, and Ca sprays had no effect on leaf composition and on any fruit attribute (soluble solids, titratable acidity, starch pattern index, flesh firmness, and concentrations of N, K, Ca and Mg). In the season of 2000/ 2001, however, when yield was 18 t ha -1 and fruits had an average weight of 175 g, the incidence of bitter pit plus lenticel blotch pit on stored fruits was 24% in the treatment with no calcium sprays and it decreased up to 2% in that with 12 sprays. Two seasons later, yield was also low (25 t ha -1 ) and fruits were large (168 g each), but they did not show any physiological disorder regardless of the number of Ca sprays. It seems that the incidence of Ca related disorders in 'Gala' apples grown on limed soils in Brazil with no excess of any nutrient only occurs on seasons with low crop yield, as a result of large fruits and a high leaf/fruit ratio, associated with some unknown environmental conditions. Index terms: Malus domestica, nutrition, bitter pit, lenticel blotch pit, calcium chloride. Frutos de mesmo tamanho e com mesmo nível de maturação foram analisados na colheita e após 5 meses de armazenamento em câmaras frigoríficas convencionais (-1 o C e 90-95% UR). Em cinco das seis safras, não houve incidência de distúrbios fisiológicos nos frutos em nenhum tratamento, e as pulverizações com Ca não afetaram a composição química das folhas e nenhum atributo dos frutos (sólidos solúveis, acidez titulável, índice de iodo-amido, firmeza e concentração de N, K, Ca e Mg). Na safra de 2000/2001, entretanto, quando a produtividade foi baixa (18 t ha -1 ) e os frutos apresentavam um peso médio de 175 g, a incidência de "bitter pit" e a depressão lenticelar atingiram 24% das maçãs que não foram pulverizadas com Ca, tendo diminuído para 2% nas que receberam 12 pulverizações. Dois anos mais tarde, a produtividade foi novamente baixa (25 t ha -1 ), e os frutos foram grandes (168 g), mas não houve incidência de nenhum distúrbio fisiológico, independentemente do número de pulverizações com Ca. Verifica-se, portanto, que o aparecimento...

Calcium sources applied to soil can replace leaf application in ‘Fuji’ apple tree1

“…Corroborating this result, Ernani et al (2008) also found that foliar calcium chloride application did not affect calcium concentration in the flesh of 'Gala' apples, in 5 of the 6 crop seasons assessed, despite spraying each crop 12 times. Neilsen & Neilsen (2002) evaluated the effect of preharvest foliar calcium chloride application of three apple cultivars ('Gala', 'Fuji' and 'Jonagold') grown in Canada and found a small increase in fruit calcium content, depending on the year, cultivar and number of applications.…”

“…For example, nine foliar applications of 0.6 % calcium chloride increased flesh firmness, reduced rottenness and lowered ethylene production in 'Fuji' apples stored for 9.5 months in a controlled atmosphere (1.2 kPa of O 2 and < 0.5 kPa of CO 2 ), at -0.5 ºC (Brackmann et al 2010). However, in five of the six crop seasons assessed, foliar application of 0.5 % calcium chloride showed no effect on bitter pit incidence, calcium concentration or flesh firmness in 'Gala' apples cold stored (-1ºC and 90-95 % RH) for five months, even with 12 foliar calcium sprays per season (Ernani et al 2008).…”

Soil composition and nutritional status of apple as affected by long-term application of gypsum

“…in addition, since the applied sulfate is not specifically adsorbed by the soil solid constituents, Ca mobility in the soil profile is high after applying this salt (ernani, 1986; ernani et al, 2001). accelerated leaching of mg (rosolem & machado, 1984;Caires et al, 2003Caires et al, , 2006ernani et al, 2006) andK (rosolem &machado, 1984;ernani et al, 2006) are some of the drawbacks of large gypsum applications to soils.…”

A inibição na síntese de giberelina reduz o crescimento vegetativo em macieiras e proporciona controle de "bitter pit" nos frutos

“…Apesar de intensa pesquisa em busca de medidas de controle, atualmente, a pulverização do pomar com cloreto de cálcio (CaCl 2 ; 0,4-0,6%) é o método mais utilizado para aumentar o teor de Ca no fruto e prevenir sua ocorrência. No entanto, em trabalho realizado com o objetivo de avaliar o efeito de diferentes números de pulverizações de CaCl 2 na cultura da macieira, não foi constada redução na incidência de "bitter pit" e/ou aumento no teor de Ca nas folhas e frutos (ERNANI et al, 2008). Desta forma, faz-se necessário o estudo de outras medidas, visando a aumentar os teores de Ca e a reduzir a incidência de "bitter pit" em maçãs.…”