[Modele de pollinisation et de fertilisation pour des fruits multi-graines et son application au kiwi].
1999
Lescourret F. | Vaissiere B. | Chadoeuf J.
A model describing flower pollination and ovule fertilisation was developed. It was designed for species that require pollination among different genotypes and where the number of seeds per fruit affects fruit quality, including their size. The outcome of the model varies with the climate, the number and phenology of flowers in an orchard, the planting scheme and the choice of pollenizers. The model takes into account the presence in the orchard of various pollenizer groups. The first step of the model is a Poisson-distributed deposition of pollen on the stigmas of flowers during the effective pollination period of these flowers. The intensity of the process depends on pollen production and release by pollenizers, which in turn depends upon the number and time-distribution of flowers that open, it also depends on pollen dispersal, which is assumed to vary according to the distance between the sources and the target. The second step is a binomially distributed selection of fertile pollen grains. The third step is a random fertilisation of ovules by the pollen tubes conditional on the presence of N ovules in the ovary. This requires knowledge on the distribution of ovule numbers per flower. The fourth step is a binomially distributed selection of fertile ovules. The combination of the four steps enables to calculate the probability that n ovules out of N present in a flower are fertilised and can become seeds. Fruit set can be deduced from the model outcomes using a probability calculated according to a logistic function in terms of seed number. The model was applied to kiwifruit, which is a dioecious species. It was used to point out knowledge gaps and to suggest further research.
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