Relationship between water‐soluble Ca and other elements and bitter pit occurrence in ‘Idared’ apples: a multivariate approach

Abstract

SummaryThe mineral composition of sound fruits of Idared apple and those with symptoms of bitter pit was investigated at two sites on M9 rootstock (Sites 1 and 2) and two sites on MM 106 rootstock (Sites 3 and 4). Concentrations of N, P, K, Ca and Mg were measured. Mg and Ca concentration were determined in water soluble (WS) and water‐insoluble (WI) fractions. The sum of these fractions was regarded as the total concentration (T). At all four sites, Ca (WS) was significantly higher in sound fruit. Principal component analysis (PCA) of data from individual locations showed that the first PCA component accounted for a high proportion of total variance (85% and 70% for Sites 1 and 2 and 70% and 69% for Sites 3 and 4, respectively). Projections of the samples into the planes of the first two PCA components revealed exact classification of the bitter pit status for all samples. The projections revealed that the first PCA component was essential for classification of the status. Determination of the distribution of components of the first PCA indicated that deficiency of water soluble Ca was the most significant factor related to development of bitter pit in ‘Idared’ apples.

Mechanisms regulating apple cultivar susceptibility to bitter pit

“…These results agree with other studies showing that high susceptibility of apple fruit to BP is associated with lower levels of water-soluble Ca 2+ in the fruit (Steenkamp et al, 1983;Pavicic et al, 2004;Amarante et al, 2013) and may explain the differences in BP susceptibility between Fuji and GS despite similar skin and flesh Ca 2+ concentrations. In this case, the water-soluble pectin fraction could also contribute to the water-soluble Ca 2+ content in the fruit tissue.…”

Identification and validation of a QTL influencing bitter pit symptoms in apple (Malus × domestica)

“…The link between bitter pit and low cellular concentrations of calcium in the apple cortical tissue is well documented (Amarante et al 2006, Pavicic et al 2004, Ferguson and Watkins 1989, and lower levels of calcium in the fruits has been suggested to be caused by insufficient supply of calcium to the tissues following rapid increases in the nutrient requirement during fruit development (Greene 1991), along with possible changes in xylem functionality during fruit development (Amarante et al 2013). The uptake of macronutrients, including calcium, by plants and its allocation to various subcellular compartments and tissues is performed by transport proteins (Blatt 2004).…”

Bitter pit in apples: pre- and postharvest factors: A review

“…Apple fruits with a higher content of N have a higher concentration of ethylene and level of respiration (Fallahi et al, 2006;Sharma et al, 2012). Pavičić et al (2004) reported that the level of N in the fruit cannot be used as an indicator of bitter pit in apple cultivar 'Idaredʼ. Miqueloto et al (2011) found that fruits with symptoms of bitter pit have a higher ethylene production, respiration and titratable acidity, but lower pH, firmness, texture and Spraying with CaCl 2 during the vegetation, sometimes beginning in June, proved to be the most economically efficient measure to increase the Ca in fruit and reduce the risk of bitter pit (Peryea et al, 2007).…”

“…Some of the fractions, such as water-soluble Ca, are physiologically active and responsible for the development of bitter pit (Saks et al, 1990). Insoluble Ca fraction is bound to the cell walls and cannot play an important physiological role, while water-soluble Ca is physiologically active fraction and can change activity of the different enzymes (Pavičić et al, 2004). In bitter pit affected fruit, Ca is accumulated in the areas affected by bitter pit in surface tissue, but in unaffected fruit Ca ing rootstock, ratio of vegetative and generative growth and storage handling.…”