ABSTRACT
The average consumer may recognize different apple cultivars and associated colour, flavour and taste differences at the market, but likely is unaware of the differences in ripening physiology that impact availability of the fruit that he/she is looking at. The term ‘apple’ suggests the existence of a single fruit type with uniformity of genetics and subsequently of maturation and ripening that does not exist because the apple represents a highly variable range of fruit types arising from wild Malus species. These fruits were originally characterized by small size, high acidity, and low sugar concentrations and therefore not highly desirable for humans. In contrast, modern fruit cultivars typically have large fruit size, less acidity, high sugar concentrations, and a high percentage coverage and intensity of red skin colour. These factors are critical for marketability as they relate directly to appearance, eating quality and flavour, all of which are desired by consumers. Consumers buy with their eyes, but thereafter, an integration of texture, acid/sugar
balance and aroma volatiles that results in the eating quality and flavour expected for any given apple cultivar becomes critical. Most commercial cultivars have originated from a relatively few founder cultivars such as ‘Rosemary Russet’, ‘Jonathan’, ‘Golden Delicious’, ‘Red Delicious’, ‘Cox’s Orange Pippin’ and ‘McIntosh’ (Khan et al., 2014; Noiton and Alspach, 1996). Cultivars also have arisen from chance seedlings or bud sports from a single cultivar or developed from breeding programmes. Newly developed cultivars such as ‘JazzTM’, ‘Pink Lady®’ and ‘Honeycrisp’ have become increasingly popular while older ones are losing market appeal.
