Introduction. Xoconostles or acidic cactus pears (Opuntia
spp.) are fruits prized for their fleshy and acidic mesocarp; they
are morphologically different from cactus pears which are sweet, juicy
and seedy. Both thrive in semiarid highlands of Central Mexico,
tolerate poor soils and scanty rainfall, and have evolved into formal
crops during the last five decades. Wild xoconostles are ubiquitous
in Mexican semiarid regions. Domesticated genotypes are found in
backyards and commercial orchards. Folk wisdom attributes xoconostle
with antihypoglycemic effects, cholesterol control and obesity reduction.
The peel presents higher antioxidant capacity than strawberry, raspberry,
red plum, grapefruit, pear and apple. Our investigation describes
the main cultivars of xoconostles with horticultural value for human consumption
in Central Mexico; it contributes to the elucidation of their morphological
relationships. Materials and methods. Twenty-one accessions from
the Hidalgo and Zacatecas states of Mexico were described using 27 variables
from cladodes, flowers and fruits; significant variables were selected
by correlation and PCA, and thereafter a cluster analysis and discriminant
canonical analysis were performed. Results. Thirteen variables were
found to be significant to discriminate accessions: cladode length, number
of rows of areoles, number of areoles in the central row, pericarp
length and width, fruit length, fruit diameter, [length / diameter]
ratio, areole density, receptacle depth, fruit and peel weight,
and pulp acidity. Two canonical roots (Can) explained variability:
Can1 (fruit areola density, acidity, number of areole rows, and number
of areoles in the central row) explained 87.55%, and Can2 (peel weight,
fruit weight and fruit diameter) explained the remaining 12.45%.
Discussion. Can1 was related to plant productivity, while Can2 comprised
mainly fruit quality traits. Both of these traits are of primary
interest for human utilization and have had a clear effect on domestication. Clusters
did not match the actual taxonomic classification.