Evaluating the Effects of Water Stress On the Growth and Development of Grain Sorghum Roots.

Plant growth depends on the ability of the root system to provide physical support as well as uptake of water and nutrients from the soil. Even though plant root system development and growth is controlled by genetic factors the soil environment (rhizosphere) within which the roots grow have significant influence. The dynamic nature of the soil environment dictates the adaptability of the root system through the ability to exhibit morphological, structural, and physiological responses to maximize the acquisition of resources. The ability of roots to exploit water moisture at deep soil horizons is one of the traits associated with drought tolerance.  Even though roots form an important part of the plant and are key in water and nutrient uptake they have not been extensively studied as the above ground part of the plant. Very little information is available on sorghum roots development and their response to drought and hence the need to generate information on this crop. The purpose of this study is to quantify these responses as well as identify desirable rooting traits of grain sorghum that can be used in the development of drought-tolerant genotypes that are more. The objectives of this study are:  (i) to quantify genetic variability exhibited in root system growth and development in response to water deficits for selected grain sorghum genotypes, and (ii) to investigate spatial and temporal distributions of lateral root growth and development in these genotypes. Plants will be grown in a greenhouse and subjected to drought stress. Roots will then be harvested and analysed to evaluate the effect of the stress on rooting depth, root length, average root diameter, root-shoot ratio, root architecture as well as composition of metabolites within the roots.