Non-climatic Factors affecting the Shape of Apple Fruits

Abstract

SOME factors affecting fruit shape of apples are known. Partially seeded fruits are one-sided, the less fleshy side being adjacent to seedless carpels. Horticulturists have long observed that climate may also affect shape. Fruits grown in hot climates, especially where nights are warm, are flatter than those from cooler climates. In 1914, Shaw¹ stated: “There is a pretty constant fluctuation between the form of the apple and the temperature for a period following bloom ; the cooler this period the more elongated the apple”. In an effort to delimit this period, he concluded that the period from the sixth to the sixteenth days following full bloom fitted the observed fluctuations in form more closely than any other period. A recent study by Westwood², however, showed that very young fruits were distinctly elongated but became more flattened as they grew, the ultimate shape being determined about 100 days after full bloom. Thus, any effect of climate on shape might possibly extend well beyond a brief period after bloom.