Evolution under domestication of correlated traits in two edible columnar cacti in Mexico
2022
Bravo-Avilez, David | Zavala-Hurtado, José Alejandro | Rendón Aguilar, Beatriz
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 component, and branching rate as tolerance component, number of fruits produced in 1 year, number of seeds/fruit and germination rate as fitness components. The differences between species, forms of management and regions were estimated with a Nested ANOVA. A Multiple Correlation Analysis was followed between all traits at the species level and forms of management within each species. We found differences in mean values between species, forms of management and regions. Significant correlations between damage, defense strategies and fitness were detected in both species and forms of management, some of them concordant with domestication syndrome: More damage/less resistance, or more damage/more branching rate. Our results suggest that S. pruinosus evolved a tolerance response under human management, while S. stellatus has not modified any of them through the same process. Also, domestication process has influenced the mean values of some traits, but not all the correlations.
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