Intraspecific Trait Variation in Cacao Agroecosystems: Influence of Local Conditions and Cultivars, and Role in Local Knowledge Systems

Intraspecific functional trait variation (ITV) in agroecosystems indicates changes in crop plant function due to genetic, environmental, and management effects. Such variation may also underpin farmersâ knowledge and management practices. I measured ITV in six Central American cacao cultivars (Theobroma cacao L.) by collecting leaves (n=519) from cacao trees (n=173) in two clonal gardens and analyzing them for a suite of functional traits. Chemical traits were related to environmental factors, morphological traits to genetic factors, and physiological traits to a combination of the two. To assess the use of ITV in farm management, I interviewed 45 farmers using a visual elicitation device containing leaves arranged by size, colour, and thickness. Participants linked leaf size to cacao production, leaf colour to shade and plant health, and leaf thickness to shade. This thesis uses ITV to demonstrate how cacao cultivars respond to environmental conditions, and how farmers interpret variation in cacao traits.