The development of inbred lines is the fundamental part of a hybrid breeding program in maize. Most of the effort takes the evaluation of combining ability of inbreds – testcrosses have to be estimated in replicated multi-location trials. Due to a very low frequency of lines with a good combining ability (0,01%), a successful breeding program has to operate with a constantly updated large number of inbreds produced from a wide variety of germplasm. Alternatively, an improvement of elite lines, parent lines of commercial hybrids, can be carried out. Special crossing schemes, such as backcrosses, are usually applied to improve inbred lines for desirable traits and characteristics; however, in most of the cases, they lead a grain-yield decrease in their hybrids. Artificial mutagenesis can also be used to produce genetic modifications within a homozygous material (inbred lines) developing thus an initial material for breeding work. Chemical mutagens were applied to induce mutations in a well-known inbred line B73. Selection for a higher grain productivity and earlier flowering was carried out in the progeny of a mutagenetic plant (M1). As a result, six new versions of this line, B73(V1V6), were developed and estimated:  five new lines significantly exceeded the initial one for grain productivity and had a much earlier flowering – from 7 to 10 days. Almost the same flowering time differences have been revealed in the estimation of the hybrid B73 x Mo17 and six hybrids between the new lines and Mo17. Three new hybrids significantly exceeded the initial one for grain productivity. Thus, the obtained results allow us to consider the applied mutation-breeding method as a possible useful tool in the improvement of inbred lines for both per se performance and combining ability. During the last three years, mutagenic plants have been obtained in Mo17 and several inbred lines which are widely used as the parent lines of local commercial hybrids. The applied mutation-breeding approach requires further studies and all interested parties are invited to collaborate on this project.