Plant Biomass Productivity Under Abiotic Stresses in SAT Agriculture

1.1 Prevalence of abiotic stresses in SAT agriculture The semi-arid tropics (SAT) include parts of 48 countries in the developing world: in most of India, locations in south east Asia, a swathe across sub-Saharan Africa, much of southern and eastern Africa, and a few locations in Latin America (Fig 1). Semi-arid tropical regions are characterized by unpredictable weather, long dry seasons, inconsistent rainfall, and soils that are poor in nutrients. Sorghum, millet, cowpea, chickpea, pigeonpea and groundnut are the vital crops that feed the poor people living in the SAT. Environmental stresses represent the most limiting factors for agricultural productivity. Apart from biotic stresses caused by plant pathogens, there are a number of abiotic stresses such as extremes temperatures, drought, salinity and radiation which all have detrimental effects on plant growth and yield, especially when several occur together (Mittler 2006).