Seedling survival of abiotic stress: Sorghum and pearl millet

This paper reviews the responses o f sorghum and pearl millet seedlings to abiotic stress and considers the implications for crop production, particularly with respect to the arid and semi-arid tropics. The growing season in much o f this area is characterized by high temperatures, high evaporative demand, unreliable and irregular rainfall, and soils o f poor structure, low fertility, and low water-holding capacity.. Poor seedbed preparation and inadequate sowing methods can increase the likelihood o f abiotic stresses developing. Such conditions result in reduced seedling growth rates/ injury, and ultimately mortality during the germination and seedling emergence stages. The wide range o f causes o f stand failure means there is no single solution. For a given target environment it is necessary to define the reasons for a stand establishment problem and to understand the requirements o f the farmer. Genetic variation for seedling stress tolerance, however, has been shown to exist in both sorghum andpearl millet. Screening techniques have been developed and used in population improvement programs and in identification o f molecular markers linked to the thermotolerance trait. Potential thus exists fo r the genetic improvement o f these crops for survival o f abiotic stresses to complement solutions brought about by changes in agronomic practice