Traditional management and morphological variation in Leucaena esculenta (Fabaceae: Mimosoideae) in the Mixtec region of Guerrero, Mexico.
Ethnobotanical information about uses, management and traditional classification of Leucaena esculenta by the Mixtec in Guerrero, Mexico, is presented. This plant is mainly used as human food. Buds of leaves and flowers as well as seeds and young pods are the main edible parts. Size, flavour and digestibility of seeds and pods are shown to be important in the Mixtec classification of Leucaena species and in selection of trees to harvest during gathering. Artificial selection in L. esculenta subsp. esculenta by the Mixtec occurs not only under cultivation, but also in wild populations where people eliminate some individuals while promoting the growth of others with favourable phenotypes. Morphological characters of seeds and pods of individual trees of subsp. esculenta were measured in order to compare phenotypic variation in populations subject to different regimes of management. Samples of trees were analysed from (a) a wild population not affected by intentional disturbances; (b) a wild population selectively managed in situ; and (c) a sample of cultivated individuals. Ordination methods and analysis of variance were used to examine differences between populations. A marked divergence between the three samples was found, especially between the managed and unmanaged wild populations. The frequency of the phenotypes preferred by people was higher in the wild population managed in situ. The study confirms that through in situ forms of management, people are able to modify the phenotypic structure of plant populations. Possible routes of plant domestication within plant populations in situ are suggested.