Effects of Fruit Load and Intra-inflorescence Competition of Fruits on Apple Growth During Fruit Development

Abstract : Ecophysiological sink-strength models, developed for fruit growth at fruit shoot level, considered each fruit as one sink. It has been already developed for several fruits excepted for apple. Variable number and size of apple fruit, developing within each inflorescence, needs therefore some adaptation. We have assumed that inflorescence sink strength, depending on fruit load, could interact with each individual fruit growth by modulating global influx into inflorescence and by regulating the nutriment fraction available for each fruit. The aim of this study was to validate these hypotheses using the average daily growth rate of each inflorescence (AGR) as a quantitative evaluation of inflorescence growth rate and dynamic of fruit drop as the factor of variability. In an experimental orchard, anthesis dates and fruit diameters were collected for Elstar cultivar from early growth stage to maturity. From all the data and according to what described in literature, we have defined five growth periods: one during cell division, three during cell expansion and one during fruit maturation. Without unloading, single-fruit inflorescences exhibited a greater AGR than two-fruit or three-fruit inflorescences with a more significant effect during first stage of cell expansion. However there was not significant difference between AGR of two-fruit and three-fruit inflorescences. Therefore we assumed that results were not only related to a weak in nutriment availability. Another or a complementary regulating process must have occurred. Besides, an unloading to one fruit in period 2 or an unloading in period 3, increased the AGR values which reached or were significantly greater than those of inflorescences which always maintained one or two fruits, respectively. Such an increase in growth rate induced by unloading was sustained during the next periods. It seems therefore that regulation process depend not only on actual load but also on the previous events.
Type de document :
Communication dans un congrès
Acta Horticulturae. 28th International Horticultural Congress, Aug 2010, Lisbone (PO), Portugal. 8 p., 2011
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https://hal-agrocampus-ouest.archives-ouvertes.fr/hal-00841720
Contributeur : Catherine Cliquet <>
Soumis le : vendredi 5 juillet 2013 - 14:39:25
Dernière modification le : mercredi 21 mars 2018 - 16:08:09

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  • HAL Id : hal-00841720, version 1

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F. Sané, Pascale Guillermin, Jean-Claude Mauget, Mickaël Delaire. Effects of Fruit Load and Intra-inflorescence Competition of Fruits on Apple Growth During Fruit Development. Acta Horticulturae. 28th International Horticultural Congress, Aug 2010, Lisbone (PO), Portugal. 8 p., 2011. 〈hal-00841720〉

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