<p style="text-align: justify;">The maize hybrid DK404SR was developed from sethoxydim tolerant inbred lines. The original sethoxydim tolerant mutant line (S2) was selected as a somaclonal variant from maize embryo tissue grown under sethoxydim selective pressure. The process involved growing somatic embryos on sethoxydim enriched media. From the somatic embryos that survived, the somaclonal variant cell line S2 was selected and subsequently regenerated. This S2 line was backcrossed at least six times with both parental lines of the hybrid DK404SR to transfer the sethoxydim tolerant trait.</p>
