Adaptation of Fruit Trees to Different Elevations in the Tropical Andes
Gerhard Fischer, Helber Enrique Balaguera-López, Alfonso Parra-Coronado, Stanislav Magnitskiy
Abstract
The adaptation of fruit species to higher elevations is generally related to climatic conditions, such as lower temperatures and partial pressure of gases and, importantly, higher solar radiation, especially ultraviolet (UV)-B, as elevation increases. Decreases in temperature, about 0.6–0.7°C per 100 m of tropical elevation, increase plant phenological cycles and facilitate the introduction of fruit species from subtropical and temperate climates to the inner tropics. In the Colombian Andes, many fruit species are grown up to 2,600–2,800 m above sea level (a.s.l.) but the Andean blueberry and banana passionfruit withstand up to 3,200 m a.s.l. Many fruit species and cultivars from the tropics have developed mechanisms of tolerance to UV-B radiation, particularly leaves that are smaller and thicker with a more resistant cuticle and, in some cases, a dense pubescence and increased number of stomata at higher altitudes (e.g., the cape gooseberry). Other physiological adaptations of fruits to increased elevations and UV-B radiation include the accumulation of pigments, such as anthocyanin or carotenoids, and a better antioxidant system. In this chapter, we discuss implications for climate and the mechanisms that fruit species use to withstand these conditions in the high tropics. Climate change makes it difficult for species to adequately adapt, but plant breeding and new varieties facilitate continued fruit cultivation in the high tropics.