Growth kinetics and determination of shape and size of small and large avocado fruits cultivar ‘Hass’ on the tree

Abstract

The shape and size of detached avocado fruit ( Persea americana cultivar ‘Hass’) were analysed throughout the growing season. Formulae and procedures developed from this analysis were used to calculate growth kinetics of small and large fruits on the tree. The spatial shape factor ( M) of the fruit was calculated from the volume ratios of the sampled fruit and its circumferential cylinder. This spatial shape factor of the fruit remained almost constant throughout all the stages of fruit growth, including the early one, when fruit length increased relatively more than fruit diameter. The growth of small and large fruits expressed on a logarithmic scale was found to be in close fit (coefficient of determination R 2 = 0.99) to the hyperbolic function Y = (A + B) X . Extrapolation of the growth curves indicated a few days difference in set of the small and large fruits. The small and the large fruits were different in shape as well as in growth kinetics. The length diameter ( L D ) ratio of both large and small fruits increased gradually and reached an ultimate stationary level which was higher for the large fruits than for the small fruits.