The objective of this research was to describe agromorphological variability of Oaxaca populations of tusta pepper (Capsicum annuum L.). 31 accessions or sample collections were taken from Santa María Tonameca and Santo Domingo de Morelos, Oaxaca, Mexico. The phenotypic variation was described and classified; hence, pepper samples were sown, transplanted, and characterized at greenhouse conditions in Madgalena Apasco, Oaxaca, from November 2012 to January 2013. The transplantation was done under a randomized complete block design with three replications. Significant differences between means of tusta pepper populations were determined for plant height at 60 and 120 days after transplantation, stem diameter, days to flowering, number of fruits, and fruit length and width. On the other hand, in phenotypic diversity patterns, important differences were determined between the populations from Santa María Tonameca and Santo Domingo de Morelos The latter were highly variable in the characters evaluated. Three phenotypic diversity groups were determined in traits associated to plant, fruit, and yield per plant. The highest weight loss (up to 13.3 g) during 30 days of storage at room temperature was quantified for the fruits of major size and density, indicating high water content.

Keywords: Capsicum annuum, phenotypic diversity, agroecological niches, agromorphological variability.