An inbred broccoli line, designated GKO-1 is disclosed. The invention relates to the seeds of inbred broccoli line GKO-1, to the plants of inbred broccoli line GKO-1, and to methods for producing a broccoli plant produced by crossing the inbred line GKO-1 with itself or another broccoli line. The invention further relates to hybrid broccoli seeds and plants produced by crossing the inbred line GKO-1 with another broccoli line. The invention further relates to methods for producing a broccoli plant containing in its genetic material one or more transgenes and to the transgenic plants produced by that method and to methods for producing other inbred broccoli lines derived from the inbred GKO-1.