Flower anthesis variability and influence on peach abscission and early growth variabilities.

This study attempted to explain peach abscission and early growth variabili ties. We assumed that flower anthesis variability was indicative of early c ompetition for carbohydrates, presumedly determinant for fruit set and earl y growth. From this viewpoint, the fruits resulting from early flowers shou ld be advantaged. In a first step, we described and analysed the pattern of flowering dates within peach trees. In a second step, we studied the relat ionship between this pattern and the variability of fruit abscission and gr owth. At the tree level, the flowers started opening from the base towards the top, but at the shoot level the flowers opened from the apex down to th e base. Single flowers opened 1 d earlier than associated flowers, which op ened independently. However, the relationships between either fruit set or growth and date of flowering did not fit our hypothesis. For example, fruit s from the late flowers had the best set. Thus, the initial hypothesis shou ld be rejected while the influence of other factors should be considered. O ur observations suggest that post-bloom temperatures could affect fruit set and early growth.