There’s growing interest in raising canola seeds for the biodiesel industry, but not in Skagit County. Seed growers would like the state Department of Agriculture to create a canola-free zone. It would cover all of Skagit County, along with parts of Island, Whatcom, Snohomish and Clallam counties. The growers worry that canola could cross-pollinate with certain vegetable seeds, particularly cabbage, and hurt the area’s $20 million seed industry.