Fruit morphological ordenation and classification of mixtec landraces of pitaya (Stenocereus pruinosus) at Mexico

Abstract

In order to classify and order the fruit morphological variation of 31 cultivated variants of Stenocereus pruinosus, identified by more than 20 informants from the Mixteca Baja region of Mexico, 19 morphological attributes were measured on 200 fruits (2-10 fruits per variant). Data were analyzed using means comparison, cluster and principal components analysis. Informants identified the variants by color, size and shape of fruits; size and color of spines; size and number of seeds; sweetness, flavor and ripeness season. Although five attributes (peer thickness, number of areoles, thickness and width of seed; fresh weight relationship between flesh and peer) were statistically similar between variants, the multivariate analysis supports 16 for the characterization of variants. The first three principal components (CP) explained 60 % of the variation and ordered the variants by size and weight of fruit and size of seed and spine(CP1), color of flesh and peer (CP2), and fruit roundness (CP3). A consistent classification with these analysis defines nine groups, one of which is a putative interspecific hybrid. The traditional classification is confirmed by statistical analysis.