Carotenoid Content in Field-grown versus Greenhouse-grown Peppers: Different Responses in Leaf and Fruit

Abstract

The carotenoid content of fresh fruits, like chiles or peppers (Capsicum annuum L.), is a desirable fruit quality trait because these compounds increase the nutritional value of the fruit. Carotenoids in general serve as antioxidants, whereas specific carotenoids are pro-vitamin A types and yet others are necessary for retinal pigments. In the plant, carotenoids function to harvest light energy during photosynthesis, act as antioxidants in multiple cell types, and pigment fruit and flowers to attract pollinators and seed dispersal agents. All of these cells presumably accumulate carotenoids through the same biosynthetic pathway. We investigated the relationship between light levels in the growth environment and the carotenoid levels that accumulated in mature fruit and leaves. Three chile cultivars with orange fruit, ‘Fogo’, ‘Orange Grande’, and ‘NuMex Sunset’, were grown under three different light conditions, shaded greenhouse, unshaded greenhouse, and field in Las Cruces, NM. Foliar carotenoid increased approximately twofold with increased light, whereas carotenoid content in fruit decreased two- to threefold with increased light. All cultivars showed identical trends with light despite having cultivar-specific carotenoid accumulation patterns in their fruit.