Genotype-environment interactions shape leaf functional traits of cacao in agroforests

The outbreak of frosty (Moniliophthora roreri) and black pod (Phytophthora palmivora) in Central American cacao agroforests throughout the 1980s, led to the breeding of Theobroma cacao clones resistant to these diseases. However, while clonal disease resistance has been well documented, clonal adaptability to contrasting pedoclimates remains less understood. Plant functional responses to environmental constraints can be assessed by evaluating intraspecific trait variation (ITV), but trait-based approaches have rarely been implemented in genotype assessments. The objective of our study was to determine cacao clone ITV in contrasting environments. Here, we used bivariate, multivariate, and functional trait space analyses to quantify ITV in nine leaf functional traits, among six disease-resistant cacao clones, growing in two clonal gardens with distinct environmental characteristics (a “Mild dry season” with near-optimal cacao growing conditions, and a “Harsh dry season” site with sub-opti...