In Mexico, diverse morphotypes of chili pepper with local recognition are distributed regionally contributing to the in-situ conservation of Capsicum diversity in the hands of farmers, as is the case of Huacle pepper in Oaxaca. The objective of this study was to evaluate the variation among morphotypes of Huacle, Guajillo, Ancho and Pasilla chili peppers, based on agromorphological traits, bioactive compounds and antioxidant activity in fruits. The morphotypes were established in greenhouse conditions under a random block design, obtaining fruit at physiological maturity for laboratory analysis. Significant differences (P ≤ 0.01) were determined in the analysis of variance among and within morphotypes for all the agromorphological characters evaluated, except in plant height at 120 days after transplantating (dat) and specific weight. Different growth patterns were evaluated from 30 to 120 dat, but the final height was similar. Size, weight, shape, pericarp thickness, locules, number and total weight of fruits per plant were used to determine the variation among and within morphotypes. Morphotypes of Huacle (CH-4, CH-9 and CH-15) and Ancho (AN-R) presented the highest values of fruits, total weight and a low number of fruits per plant. Among morphotypes, significant differences (P ≤ 0.01) were observed for fruit composition, but not for antioxidant activity. Also, significant differences were seen in vitamin C, flavonoids content, and antioxidant activity. In fruit composition, Huacle and Guajillo peppers presented a higher vitamin C content (4.5 mg acetic acid g-1). Huacle pepper was also high in total polyphenols (31.5 mg GAE g-1). Ancho pepper showed a higher content of carotenoids (2.8 mg β -carotene g-1) and total flavonoids (3.3 mg QE g-1). Pasilla pepper showed low values in all the evaluated compounds. In conclusion, all morphotypes showed variation in fruit characters (weight, length, width, pericarp thickness, number of locules and fruit length/width ratio). In fruit composition, the variation was in vitamin C, carotenoids, flavonoids and polyphenols, but not in antioxidant activity. Key words: Morphotypes, Huacle pepper, Ancho pepper, Guajillo peppers, fruit composition, phenolic compounds, vitamin C, antioxidant activity
