Evolution Under Domestication of Correlated Attributes in Two Edible Columnar Cacti in Mexico

Abstract

Abstract Stenocereus pruinosus and S. stellatus are columnar cacti from central Mexico, distributed in the Valle de Tehuacán and the Mixteca Baja regions. Both species have populations subject to three different forms of human management: wild, in situ and cultivated, growing in sympatry. The objectives of the present study were to compare variation in damage levels, defense mechanisms and fitness components between 1) both species due to differences in the intensity of management; 2) populations of both species subject to different forms of management; 3) two regions with different management practices and physical conditions, in these two columnar cacti. We estimated the percentage of damage, abundance of spines as resistance, and branching rate as a tolerance component, number of fruits produced in one year, number of seeds per fruit and percentage of seed germination as fitness components. The differences between species, forms of management and regions were estimated with ANOVA tests. A paired correlation with the measured variables within each form of management was used to observe the correlated attributes in both species. We found differences between species, forms of management and regions, mostly concordant with the domestication syndromes. More managed populations, present more damage and less resistance, without compromising fitness, which is the target attribute. Correlated attributes exhibited significant correlations in both species and forms of management. Some of them were concordant with domestication syndrome: More damage/less resistance, or more damage/more branching rate. Our results show that human management can influence the evolution of the interaction of correlated attributes like defense mechanisms, damage and fitness in these columnar cacti.