The Organic Seed Alliance, Port Townsend, Wash., has published four plant breeding manuals to walk organic farmers through methods of developing new crop varieties.

They include an introduce to on-farm organic plant breeding and three crop-specific manuals covering carrots, sweet corn and tomatoes, according to a news release.

The introductory manual provides the scientific foundation for the crop-specific instructions provided in the other three guides.

Each crop-specific manual provides step-by-step instructions from identifying good breeding material to maintaining the new variety for quality and uniformity.

The manuals are available for free download from the Organic Seed Alliance website.