Seed production in corn and soybean

Seed production is one of the least visible yet most important aspects of food and feed production. This part of the system is often taken for granted, even by the farmers who plant the seed. One of the reasons is that much of the seed in the United States is provided by the private sector, particularly for corn and soybean. Also, seed production is a technical process that requires in-depth knowledge of the reproductive mechanisms in plants. Disciplines Agricultural Science | Agronomy and Crop Sciences | Plant Breeding and Genetics Comments To visit Union of Concerned Scientists site, go to ucsusa.org. This report is available at Iowa State University Digital Repository: http://lib.dr.iastate.edu/agron_reports/4 54 l Union of Concerned Scientists l SEED PRODUCTION IN CORN AND SOYBEAN Chapter 4 A U T H O R : Kendall Lamkey Seed production is one of the least visible yet most important aspects of food and feed production. This part of the system is often taken for granted, even by the farmers who plant the seed. One of the reasons is that much of the seed in the United States is provided by the private sector, particularly for corn and soybean. Also, seed production is a technical process that requires in-depth knowledge of the reproductive mechanisms in plants. For the purposes of this chapter, seed production has been defi ned broadly as the series of steps that begins with the breeding of a new variety and ends with seed that is sold to farmers (Figure 4-1). The seed production process is usually conducted by three or four specialized departments in a seed company. Plant breeders develop varieties and produce breeder seed—the source seed from which all varieties are propagated. Some companies now have separate departments that do all breeder seed production. In the case of corn, breeders will also be responsible for adding male sterility if needed. Parent or foundation seed production is usually done by a separate department. The production of hybrid or certifi ed seed—the seed that will be sold to farmers—is done by yet another department. Seed producers have many goals, but this chapter focuses on a detailed description and analysis of the steps depicted in Figure 4-1 with regard to maintaining genetic purity. Genetic purity is important because gardeners and farmers expect varieties with the same names to be identical from one year to the next. We are concerned with two sources of contamination: impurity resulting from physical mixing of seed and impurity resulting from the movement of pollen. The seed production process is described in suffi cient detail to identify points 20 A variety is a subgroup of plants within a species whose genetic makeup and characteristics distinguish it from other varieties of the species. Crop varieties are often called cultivars, especially by agricultural scientists. Figure 4-1 The Seed Production Process Breeders make a cross to develop a new variety