Domestication of Dacryodes edulis: 2. phenotypic variation of fruit traits in 200 trees from four populations in the humid lowlands of Cameroon

Abstract

Within a wider tree domestication programme, the purpose of this study was to quantify the tree-to-tree variation in fruit traits as an aid to plus- tree selection. Detailed measurements of 10 fruit traits for 24 fruits from each of 200 Dacryodes edulis trees were made from four villages in the humid lowlands of Cameroon. Highly significant (p<0.001) differences were found in mean fruit length (33.5 to 122.4 mm), fruit width (23.3 to 53.5 mm), flesh depth (0.6 to 11.1 mm), fruit mass (10.0 to 114.0 g) and flesh mass (12.5 to 106.0 g). For each of these traits, continuous variation was evident. In addition, fruits displayed differences in skin and flesh colour, taste and oiliness. The most frequent skin colour was greyish-violet (Methuen Colour Code 18D) and for flesh colour was yellowish (Methuen Colour Code 29A7). With the exception of kernel mass, traits differed significantly between the four villages but no significant differences were found between the different land use systems (home garden, cocoa farms, forest fallow, or crop field). This paper provides the first quantified description of tree-to-tree variation in fruit characteristics within populations of D. edulis in Cameroon, and also describes a methodology for evaluating future collections from which to select superior phenotypes for cultivar development.