Development of Corn Lines 676, 678, and 680.  Male sterile and glufosinate-tolerant<br> corn lines 676, 678, and 680 have been developed to provide a more reliable system to<br> generate hybrid seed corn by genetically engineering a plant to be male sterile.  As<br> described in the petition, these corn lines, have been genetically engineered to contain an<br> adenine methylase, or dam gene derived from Escherichia coli (Brooks et al., 1983). <br> The dam gene expresses a DNA adenine methylase enzyme (DAM) in specific plant<br> tissue, which results in the inability of the transformed plants to produce anthers or<br> pollen.  The subject corn lines also contain the pat selectable marker gene isolated from<br> the bacterium Streptomyces viridochromogenes.  The pat gene encodes a<br> phosphinothricin acetyl transferase (PAT) enzyme (Thompson et al., 1987), which,<br> when introduced into a plant cell, confers tolerance to the herbicide glufosinate. <br> Linkage of the dam gene, which induces male sterility, with the pat gene, a glufosinate<br> tolerance gene used as a marker, enables identification of the male sterile line for use in<br> the production of hybrid seed.  The subject corn lines were transformed by the particle<br> gun process (Klein et al., 1987) and expression of the introduced genes is controlled in<br> part by gene sequences derived from the plant pathogen CaMV.