Influence of enhanced UV-B radiation on wheat production in relation with abiotic, biotic and socioeconomics constraints

The light is one of the most important factors that regulate growth and development of plants. However, the increase of the ultraviolet-B radiation due to the anthropogenic action can have negative impacts on these processes, producing a decreased photosynthesis and biomass production. Zonal average ultraviolet irradiance (flux ultraviolet, FUV) reaching the Earth’s surface has significantly increased since 1979 at all latitudes except the equatorial zone. Depletion of the stratospheric ozone layer leads to an increase in ultraviolet-B (UV-B: 280- 320 nm) radiation reaching the Earth’s surface, and the enhanced solar UV-B radiation predicted by atmospheric models will result in reduction of growth and yield of crops in the future. Over the last two decades, extensive studies of the physiological, biochemical and morphological effects of UV-B in plants, as well as the mechanisms of UV-B resistance, have been carried out. In this review we didn’t obtain evidences to show that the increased UV-B radiation influences the oscillations observed in the wheat production in major producing countries in the world. The most important constraints observed on wheat production are heat (affecting up to 57% of the entire wheat area in surveyed countries), competition with weeds, and diseases (both affecting up to 55% of wheat area). Of the socioeconomic constraints listed and evaluated, the access to mechanization and availability of credit were the most often highlighted. The way to improve wheat production in the new scenarios consequence of global environmental changes is the genetic breeding. Breeding wheat cultivars with increased grain yield potential, enhanced water-use efficiency, heat tolerance, end-use quality, and durable resistance to important diseases and pests can contribute to meet at least half of the desired production increases. The remaining half must come through better agronomic and soil management practices and incentive policies.