Relationships between flower position, shoot structure and fertility for the main Tunisian almond cultivar ‘Achaak’

The Tunisian almond cultivar 'Achaak' is the most important in terms of market demand and fruit quality but unfortunately it is commonly considered as a low producing genotype. Some observations have indicated that this may be due to the lack of some major technical growing practices. However no much data is available to give a scientific explanation for this problem. The objective of this study is to analyze the fertility of the flowers of this cultivar according to flower position and to describe its fruiting structures in comparison to the highly fertile Italian cultivar 'Tuono'. Architectural details of three branches on three trees were described and inventoried. Each branch was characterized (age, length and diameter) and their composition was registered (shoots, spurs, flower buds, fruit). There was a clear divergence in the architecture of the two cultivars and this provided information regarding some problems with 'Achaak'. In 'Tuono' a majority of highly fertile flowers and consequently fruits were present on spurs while 'Achaak' bore mainly on lateral or long 1-year-old shoots with the presence of some short shoots that only cropped once. Additionally, this result provided valuable information for improving the productivity of the 'Achaak' cultivar by applying specific tree training systems and orchard management practices.