Advances in Improving Adaptation of Common Bean and Brachiaria Forage Grasses to Abiotic Stresses in the Tropics

Agriculture occupies about 38% of the Earth’s terrestrial surface. Croplands cover 1.53 billion hectares, while pastures cover another 3.38 billion hectares (Foley et al., 2011). Between 1985 and 2005, the world’s croplands and pastures expanded by 154 million hectares with a net redistribution of agricultural land toward the tropics, with implications for food production, food security, and the environment. Over one billion people are hungry and living in poverty, and 75% of them live in rural areas and depend on agriculture for their livelihoods, with the majority relying on small-scale crop-livestock systems. To meet the food needs of the expected 9.2 billion people in 2050, agricultural production has to increase by 70% compared to what it was in 2000. About 90% of this

39.1 Introduction .......................................................................................................................... 847 39.2 Major Abiotic Constraints for Crop and Forage Production in the Tropics .........................849