18 populations from mutual crossing of 6 winter wheat varieties (Akteur, Meritto, Sakura, Simila, Sulamit, Vlasta) were evaluated in shooting and in heading by its electrical capacitance in F3 and F4 generations and selected for great (A) and small (B selection) root system size (RSS). Progenies of A plants in F3 had also greater RSS in F4, and progenies of B plants in F3 had also smaller RSS in F4. From the selection difference in F3 was inherited in selection A into the following generation 43%, in selection B 18%. The selection for the RSS was therefore effective with higher response for greater RSS, what can be evolutionary advantageous. The RSS of the 18 combinations was significantly correlated not only to the respective parents, but also mutually in A and B selection. Variety Akteur increased RSS in its progenies. Correlation between RSS and grain yield in F3 generation was significant. The grain yield increment was inherited into following generations F4 and F5 insignificantly (by 14 and 9 %, respectively). These results show efficient selection for RSS, related to grain yield; the selection can be used for breeding for drought tolerance.