Harry Stine, who owns an Adel-based seed company, has been listed on Forbes' list of billionaires for the first time, reports DesMoinesRegister.com. Stine, 72,  is listed as 607th on the list with an estimated wealth of $2.9 billion. Stine Seed is the world's largest privately held seed company, and it has developed soybean genetics that it has licensed to the largest seed companies.