Abstract
Cacao, a shade-tolerant cauliflorous fruit tree originating from the Amazon, is traditionally cultivated in association with other woody and fruit tree species in agroforestry systems. The heterogeneous light environment within these systems results in variations in growth and production of cacao trees. Understanding how cacao trees respond to variations in light interception is crucial for adapting crop management in agroforestry systems. We investigated the effect of two shading nets, i.e. medium and high shading (40% and 90% intercepted radiations, respectively) on the growth, architecture and flowering of two architecturally-contrasted cacao genotypes. Data were collected using multi-scale tree graphs data structure. Reproductive activity at the phytomer scale was monitored weekly for a year. Analyses showed an invariant negative effect of high shade on number of cataphylls on growth-units and on frequency of old nodes bearing flowering sites. The effect of shade on number of leaves on tree and elongation of axes , which correspond respectively to shade tolerance and shade avoidance strategies, were dependent on the genotype. By elucidating the response of cacao trees to shading, our study contributes to a better understanding of how the species respond to variations in light environment as found in agroforestry systems.