PRELIMINARY STUDY ON PEACH FLORAL DIFFERENTIATION IN MILD WINTER AREAS

In subtropical climates the main obstacle to introduced deciduous fruit trees is the lack of cold temperatures during rest period. The means often used to avoid this problem are the introduction of low-chilling requirment varieties, the choice of sites located in high altitude where temperatures are low enough to permit a normal development of trees and the use of husbandry practices to reduce bud rest or to facilitate its break. However the results obtained are often empirical and the lack of knowledge on the physiological aspects of these phenomena limits the husbandry impact of these actions.

Only a rigorous analysis of different components of fruit yield (rhythm of vegetative growth and lateral branching, floral differentiation, bud opening, flowering, fruit-set, fruit growth) relationships to the climate and the chilling requirements of varieties can lead to a rational approach to understanding physiological mechanisms determining growth and fruiting.

This scientific approach is followed by IRFA in Reunion Island for a study on peach. One of the first practical consequences of this work whose interest can be extended to all mild winter areas, is the control of excessive growth and productivity by an adapted pruning.

This paper concerns especially the differentiation of flower buds on peach cultivated in Reunion Island. A comparative study with varieties grown in temperate climates underlines the effect of genetic origin and temperatures on the floral organogenesis of peach.