Seasonal changes In the shape of Red Delicious apple frults

Patricia Garriz I.1, Marcela del Egido R.1, Alejandra Bartusch Z.1 y Armando Alvarez A.1

Seasonal changes on fruit shape were studied in apple trees (Malus domestica Borkh. cultivar Red Delicious) during three growing seasons (1986/87, 1988/89 and 1989/90) in the Alto Valle region, Río Negro, Argentina. Maximum, mean and minimum temperatures for the same periods were also analyzed. Shape variation as a function of time was hyperbolic and it filled the equation y = 0,8679 + 4.1480x 1/X2 (Y = Length/Diameter ratio, X = weeks after full bloom) for tha three seasons. The L/D ratio decreased substantially during the initial weeks of growth and it became relatively stable 100 days after full bloom; the value was 0,87 at harvest time, which corresponded to an appropriate fruit shape, according to the market requirements, Elongated fruits were characteristic of seasons with lower minimum temperatures throughout the growth periodo High negativa correlation eoefficients were obtained between the L/O ratio and the inverse values of the square accumulated temperatures (day-degrees above 5 ºC),

Keywords: apple, fruit shape, growth, temperatures.
1 Facultad de Ciencias Agrarias. Universidad Nacional del Comahue. Casma Correo 85. 6303 Cinco Saltos. R. N.. Argentina,