The differential influence of root systems on plant development under field conditions is very difficult. A field experiment was devised using three different row spacings (101,152 and 203 cm ) to screen sorghum germplasm for rooting potential based on the relative ability to explore additional soil volume for water. The hypothesis is that grain yield increases as the available soil volume increases, providing that the germplasm has the potential to produce a root system capable of taking advantage of the additional water resources. Forty lines from various germplasm backgrounds were grown in a replicated field test at two locations. Grain yield as well as other growth parameters were measured. The results demonstrated that root growth potential as measured by differences in apparant yield was significant across entries and locations. Correlations between field and laboratory seedling evaluations will also be discussed.