CHRONOLOGY OF FRUIT-DEVELOPMENT RELATIVE TO PLANT-GROWTH IN THE APRICOT PRUNUS-ARMENIACA L-CV ROUGE-DU-ROUSSILLON

The chronology of fruit development and vegetative growth is described for the apricot cultivar 'Rouge de Roussillon'. We observed a synchro ny between the major events of fruit development and those of vegetati ve growth. This allows us to complete a descriptioon of phases in frui t by taking in account the unfurling of preformed, then newly formed p arts of growth units (GU). During the first period, which lasts approx imately 12 days following full flowering, numerous events unfold simul taneously. In the absence of leaves, everything the tree produces duri ng this period depends on its reserves. During the second period (from around 12 to 30 days) cell division ceases in the future fruit and th e preformed parts of the growth units unfurl. From 30 to 60 days after full flowering, the fruit develops little, while the neoformed parts of the growth units are formed. The cessation of growth is spread out at intervals during this period and, at 60 days, 80% of GU have ceased to grow. The embryo continues its development until about 90 days, wh ile the number of growing shoots is limited. Finally, beyond 90 days, the fruit finishes its enlargement while new growth units appear on th e tree. The period of direct concurrence between vegetative and floral development seems limited to the two early periods. In effect, the pr eformed leaves in the winter bud seem to be incapable of providing ass imilates to all the growing organs. Consequently, the priority is alte rnatively vegetative growth (unfurling of newly formed leaves) then fr uit development.