Loquat fruit sink strength and growth pattern

Loquat fruit growth measured by increases of equatorial diameter adjusts to a logistic curve. By means of sequential measurements of tagged fruits of cultivar 'Algerie', curves were obtained that fit significantly to a single sigmoid model in unthinned as well as in heavily thinned trees. Equations defining growth pattern of fruits from thinned and from unthinned trees showed different slopes that reflect greater growth rates under thinning. On the contrary, small and large fruits within the same tree showed minor variations in growth rates, and fruit size at harvest was largely due to fruit size at initial fruit set. Differences in size among fruitlets of the same tree at the time of hand fruit thinning never reversed and led to different commercial categories related with initial size; that allows us to recommend fruit thinning on a size basis. A strong significant correlation was also found at harvest between fresh fruit weight and equatorial diameter. Size and number of seeds were the major determinants of final fruit size in loquat whereas number of leaves and leaf area index of the bearing shoots showed a weak correlation with final size of fruits. (C) 2003 Elsevier Science B.V. All rights reserved.