Cadmium stress tolerance in crop plants

Abstract

The presence of salts of different kinds in saline soils, and aluminium, zinc, manganese and copper in acid soils develop stressful conditions for plants, and result in poor yields of different crops. Therefore strategies have to be developed to make the plants adaptable to the unconducive environments. Better management practices could be used successfully for raising crops in the areas affected. Adaptation of some species to high salt concentrations provides evidence of the genetic potential existed in plants to cope with the unfavourable conditions. Variation, both between and within the species, and even at intra-varietal level does exist in different crops. Development of tomato, rice and barley varieties tolerant to salinity, and of maize tolerant to acidic-soils are the elegant examples in the domain of plant breeding. The studies on the genetic basis of tolerance in plants for salinity and toxicity due to aluminium, manganese, copper and zinc revealed that variation in tolerance was genetically controlled and thus heritable in nature. Thus, further improvement in tolerance to salinity and acidity may be possible utilising genetic resources available to researchers. Strong selection pressures may be used in order to identify tolerant individuals either from heterogeneous or segregating populations. Physiological mechanisms involved in controlling the responses to stress may aid in selecting successful plants. Therefore, an understanding of appropriate physiological mechanisms controlling stress tolerance is essential. Molecular analysis of genome at the DNA level is an additional tool for the breeders, and allows them to transfer and combine desirable genes with greater precision for greater benefits. The DNA marker technology is now being incorporated in breeding programmes, which has the potential to facilitate the selection for complex traits in early generations.