Traditional Management and Morphological Patterns of Myrtillocactus schenckii (Cactaceae) in the Tehuacán Valley, Central Mexico¹

Abstract

Traditional Management and Morphological Patterns of Myrtillocactus schenckii (Cactaceae) in the Tehuacán Valley, Central Mexico Myrtillocactus schenckii is a columnar cactus endemic to central México and appreciated for its edible fruit. In the Tehuacán Valley it occurs wild in thorn-scrub forests, but it is also under silviculture management—tolerate in agroforestry systems and cultivated in home gardens. Ethnobotanical and morphometric studies were conducted to document its use and management forms, as well as consequences of artificial selection on morphological patterns in managed populations. In silviculture populations artificial selection occurs through selective tolerance of the phenotypes producing more, larger, and sweeter fruits, whereas in home gardens people plant branches of the preferred phenotypes. Morphological differences were found especially in fruit size and production, the main targets of artificial selection. The highest average values of fruit size and production were found in cultivated populations (0.993 cm³ and 204.45 fruits per branch, respectively), intermediate in silviculture populations (0.819 cm³ and 70.63 fruits per branch), and the lowest in the wild (0.68 cm³ and 59.75 fruits per branch). Multivariate statistical analyses differentiated populations according to their management type. Morphological diversity was higher in managed populations (0.703 ± 0.029 and 0.679 ± 0.019 in silviculture and cultivated populations, respectively) than in the wild (0.652 ± 0.016). Managed plants of M. schenckii do not show signs of depending on humans for survival and reproduction and, therefore, domestication should be considered incipient.