Artículos científicos

Twenty-three Peruvian chili pepper accessions, belonging to the four domesticated species Capsicum annuum, Capsicum baccatum, Capsicum chinense and Capsicum frutescens, were grown under different meteorological conditions and agricultural practices in three Peruvian locations (Chiclayo, Piura and Pucallpa). Results are reported for powdered oven-dried bulk samples of each accession and each location by important quality attributes (capsaicinoids, flavonoids, tocopherols, antioxidant capacity, total polyphenols, extractable color (ASTA 20.1) and surface color). Multivariate data evaluation by principle component analysis and partial least square discriminant analysis did not show any underlying structure. Moreover, a high influence of the environment on the analyzed traits could be demonstrated by analysis of variance. Significant differences (p ≤ 0.001) between the accessions and all locations were observed for all traits. Besides, significant interaction between accessions and locations indicated that the accessions responded differently to changes of the locations. The calculation of an environmental impact factor allowed differing between chili peppers provided consistent phytochemical levels widely independent of the location or those that provided exceptional high levels for a specific trait at one of the locations.

Peru is considered a hotspot with maybe the highest diversity of domesticated chili peppers. Capsicum pubescens is the least explored domesticated chili pepper, especially with regard to its chemical composition. Thirtytwo different C. pubescens (Rocoto) accessions, out of the national Peruvian Capsicum germplasm collection at the Instituto Nacional de Innovación Agraria, were selected for investigating the phytochemical content and its variability. After drying and milling, the fruits were analyzed for the three major capsaicinoids (capsaicin, dihydrocapsaicin and nordihydrocapsaicin), flavonoid aglycons (quercetin, kaempferol, luteolin, apigenin), total polyphenol content, antioxidant capacity, tocopherol (α-, β- and γ-) content, fat content, ascorbic acid content, surface color and extractable color. The concentrations for selected traits ranged as follows: total capsaicinoids from 55 to 410 mg/100 g (corresponding to ca. 8400–60,000 SHU), total polyphenols from 1.8 to 2.5 g gallic acid equivalents/100 g, antioxidant capacity from 2.4 to 4.6 mmol Trolox/100 g and tocopherols from 6.8 to 18.4 mg/100 g. Only very few of the accessions contained detectable amounts of the major chili flavonoid quercetin. The results indicate that C. pubescens is generally less diverse and exhibits a lower content of almost all analyzed traits when compared to 147 Peruvian chili pepper accessions belonging to the other four domesticated species.

For most crops, like Capsicum, their diversity remains under-researched for traits of interest for food, nutrition and other purposes. A small investment in screening this diversity for a wide range of traits is likely to reveal many traditional varieties with distinguished values. One objective of this study was to demonstrate, with Capsicum as model crop, the application of indicators of phenotypic and geographic diversity as effective criteria for selecting promising genebank accessions for multiple uses from crop centers of diversity. A second objective was to evaluate the expression of biochemical and agromorphological properties of the selected Capsicum accessions in different conditions. Four steps were involved: 1) Develop the necessary diversity by expanding genebank collections in Bolivia and Peru; 2) Establish representative subsets of ~100 accessions for biochemical screening of Capsicum fruits; 3) Select promising accessions for different uses after screening; and 4) Examine how these promising accessions express biochemical and agromorphological properties when grown in different environmental conditions. The Peruvian Capsicum collection now contains 712 accessions encompassing all five domesticated species (C. annuum, C. chinense, C. frutescens, C. baccatum, and C. pubescens). The collection in Bolivia now contains 487 accessions, representing all five domesticates plus four wild taxa (C. baccatum var. baccatum, C. caballeroi, C. cardenasii, and C. eximium). Following the biochemical screening, 44 Bolivian and 39 Peruvian accessions were selected as promising, representing wide variation in levels of antioxidant capacity, capsaicinoids, fat, flavonoids, polyphenols, quercetins, tocopherols, and color. In Peru, 23 promising accessions performed well in different environments, while each of the promising Bolivian accessions only performed well in a certain environment. Differences in Capsicum diversity and local contexts led to distinct outcomes in each country. In Peru, mild landraces with high values in health-related attributes were of interest to entrepreneurs. In Bolivia, wild Capsicum have high commercial demand.