Manual on Plant Stress Physiology

Abstract

Drought, flooding, high temperature, cold, salinity, and nutrient availability are abiotic factors that have a significant impact on world agriculture and account for more than 50% reduction in average potential yields for most major food and fodder crops (Wang et al., 2003). These comprise mostly of high temperature (40%), salinity (20%), drought (17%), low temperature (15%) and other forms of stresses (Ashraf, 2008). Climate prediction models show increased occurrences of drought, flooding, salinity and hightemperature spells during the crop growing periods (IPCC, 2008; Mittler and Blumwald, 2010). Plant genetic resources for food and agriculture comprises of a diversity of genetic materials in the form of traditional varieties, modern cultivars, crop wild relatives and other native species that are the basis of global food security. Genetic diversity provided farmers, plant physiologists, plant breeders and biotechnologists with options to develop, through the natural selection, breeding and genetic manipulation, new crops, that are resistant to pests, diseases and adapted to changing environments (abiotic stress). Human population is increasing and is expected to grow from 6.9 billion to 9 billion by 2050. To feed the increasing population, we need to improve the food production by 60% up to 2050 with the limited land and water resources (FAO, 2012b). The demand for food and livestock production will continue to rise with the increase in global population; therefore improving production and productivity to ensure sustainable yields under changing environmental conditions is essential. To achieve this predicted global food security, we need to increase our understanding of plant responses to abiotic stress. Knowledge of natural selection, stress breeding and genetic manipulation of plants that can maintain higher photosynthetic rates, better foliage growth and improved yield under stress conditions (Condon et al., 2004; Morison et al., 2008) are must for achieving this goal. Agronomists, soil scientists, plant genetic resource (PGR) scientists, plant physiologists and plant geneticists and breeders can play an essential role in boosting crop production by collection, evaluation, documentation, identification, characterisation of stress adaptive traits and utilisation of these traits into the breeding programme for crop/forage improvement.