Favorable conditions for initial root development will result in plants better able to tolerate mid-summer dry spells. As important as root growth and development is to achieving final grain yield, most of us are fairly ignorant of what goes on below ground. The roots that you'll find developing near the seed of a newly emerging plant serve a relatively minor role in the great scheme of root development. Seminal roots provide minimal uptake of water and nutrients. Young seedlings depend primarily on energy reserves of the kernels until the permanent roots develop.
Seminal roots cease new growth shortly after the coleoptile emerges at the soil surface.
From growth stage V2 through about V6, there will be generally be one fewer set of nodal roots than number of visible leaf collars. For example, a plant at growth stage V3 will usually have 2 visible sets of nodal roots. By growth stage V6, the nodal roots are the main root system of the plant. If damage occurs to the seminal roots or mesocotyl before the nodal roots become established, stunting or death of the plant will occur. Such damage includes injury from excessive rates of starter fertilizer, seedling blight, herbicide injury, wind damage, and insect feeding damage.