Capsicum is one of the most economically important genera in the Solanaceae family. Capsicum fruits (peppers) are rich in phytochemicals with high nutritional value and significant health-promoting characteristics. The phytochemical profile of peppers consists of capsaicinoids, carotenoids, and phenolics, primarily. Currently, most of the pepper production is carried out under protected horticulture conditions. The objective of this article was to provide a comprehensive review on how light characteristics and manipulation by different horticultural technologies can affect the biosynthesis and accumulation of phytochemicals in Capsicum fruits. The use of shade nets or plastic covers to reduce light intensity does not seem to yield consistent responses on the phytochemical profile, as the final profile results from the interaction of several factors. Other factors involved in the accumulation of phytochemicals include temperature, water availability and plant nutrition. Exposure of plants to supplemental light with specific wavelengths (using LEDs) seems to result in a more precise stimulation of specific metabolites. In this article, we examine the effects of light irradiance and spectrum on the specific phytochemicals of Capsicum fruits.

Although habanero peppers ( Capsicum chinense , Jacq.) are highly appreciated as a result of their organoleptic and pungency properties, the crop faces edaphic stresses throughout Mexico. A study was conducted to determine how the photosynthetic parameters, vegetative growth, yield, and fruit quality of the plant change in response to suboptimal conditions in the substrate. Habanero plants were grown in an inert substrate (perlite) and exposed to increased salinity levels (4 and 7 dS·m ⁻¹ ) and reduced nitrogen and phosphorus conditions. Plants grown with a Hoagland-based solution were used as controls. High salinity conditions reduced the light-saturated photosynthetic rates (64% of the control) but did not compromise yield or fruit quality. This effect was possibly the result of the addition of Ca ²⁺ , which reduced salinity-induced calcium deficiency. Although comparable low nitrogen levels in previous studies were shown to cause a severe reduction in plant viability, in our study, low nitrogen reduced the light-saturated photosynthetic rates (47% of the control) and shoot:root ratio (67% of the control) but did not significantly affect yield or fruit quality. Low nitrogen and 7-dS·m ⁻¹ treatments increased fructose and glucose content (increases of 27% and 21%, respectively). Low phosphorus significantly affected plant growth and yield and reduced fructose content (73% of the control). Plants were not sensitive to low nitrogen and high salinity, possibly as a result of the use of nitrate-based fertilizers and the addition of calcium, respectively. These results provide guidelines for habanero pepper production under suboptimal edaphic conditions.

In Mexico, piquin peppers are highly valued horticultural products with limited cultivated production due to low seed germination, morphologic and genetic variability, disease susceptibility, and limited environmental physiology information. The objective of this study was to evaluate the effects of irrigation frequency and shade level treatments on vegetative growth, yield, and fruit quality of a commercial ecotype of piquin pepper. The study was conducted during two consecutive years using a hierarchical linear mixed-effects model design, with yearly data of irrigation frequency as main treatment blocks and shade levels as secondary blocks (nested within irrigation frequency treatments). Our results indicate that more frequent irrigation and increased shade levels favored vegetative growth. In addition, moderate shade levels (interception of 35% of full sunlight) and daily irrigation provided the best conditions for fruit production. This effect could be attributed to an increase in vegetative growth (thus higher photosynthetic and crop load capacity); more moderate conditions (temperatures and relative humidity) that favored flowering and fruit set, or a combination of these factors. Fruit size and pungency were not significantly affected by the treatments. Our results provide basic information for the development of guidelines for the cultivation of piquin pepper plants.

Piquin pepper [ Capsicum annuum L. var. glabriusculum (Dunal) Heiser and Pickergill] is a semidomesticated pepper with high commercial value and wide applications as fresh or processed products. Piquin pepper plants have been difficult to domesticate and cultivate because of low seed germination, genetic and morphologic variability, insect and disease susceptibility, and limited environmental physiology information. Currently, seed sterility is no longer considered a limiting factor as hormonal, chemical, and thermal treatments have been developed to overcome seed dormancy. In vitro propagation (primarily by direct organogenesis) is still not reliable for seedling production. Cropping systems of piquin pepper plants include traditional methods such as agroforestry and full sunlight, and under protected horticulture conditions, mainly shade nets. Shade levels and water availability affect yield and vegetative growth. Piquin pepper plants can be grown under diverse geographic and edaphic conditions. Nutrition and fertilization studies are limited. Biotic stresses that can cause economic damage to piquin pepper plants include most that affect other pepper cultivars. Piquin pepper is also considered an important genetic resource as it reports resistance to some viral groups, which could be used for genetic improvement of other cultivated peppers. Current research needs involve the development of dependable plant materials (cultivated varieties) with reduced labor needs, particularly during the harvest period. In addition, research is needed to reduce the susceptibility of piquin pepper plants to other plant diseases. This review presents an analysis of the aspects related to the production of piquin peppers under cultivated conditions.