Agriculture began approximately 10,000 years ago when primitive humans began using certain plant types growing in the regions they inhabited for food. Several theories exist on the specifics of how and where plants came to be cultivated. But in general everyone agrees that certain regions gave rise to crops that developed from native plants in those regions. Most major geographic land areas of the globe have crops that can be traced back to that area. Although few major agricultural crops originated in the Unite States, several minor ones can be traced to the United States.
Crops are domesticated by selecting and propagating plants with superior characteristics. The propagation can be sexual (seed) or asexual (vegetative) means. In many cases, vegetative or asexual propagation allows desirable traits to be easily passed from one generation to the next. Care must be taken to ensure that over time the daughter material has not mutated or become infected with pathogens. In some cases asexual propagation is not practical, as with most agronomic and forage crops. Therefore, propagation by seed is necessary. As long as the seeds produce plants that maintain the desired characteristic of the parent(s)(true-to-type), the seeds can be saved from one crop to produce the next. When seeds don’t produce true-to-type, then seeds that are the result of specific parental crosses must be obtained for each crop. Crop improvement has progressed from its early stages when superior plants were merely selected by a farmer and the seeds of those plants used for the next crop to modern-day methods that involve very rigid and competitive breeding and biotechnology programs throughout the world. When plants are domesticated, the result is often a loss of genetic traits that, at the time of original domestication, were not considered important or may not have been noticed. Many times these traits are what allowed the plant to survive in the wild. With time, quite often these traits do become important but are lost because the alleles that carried those traits are no longer found in domesticated cultivars. Recently humans have come to understand the value of genetic diversity and the importance of the wild ancestors of many of our crops. Plant collectors today often search for the ancestors of domesticated crops as well as for new species that have crop potential. To facilitate the collection and preservation of germplasm, centers around the world have been established, including the United States National Germplasm System.
At the start of the new millennium, the potential for crop improvement through the use of biotechnology and genetic engineering is inestimable. No longer is the genetic information carried in a plant limited to what can be obtained through compatible sexual crossing. The ability to import resistance, productivity, or nutrition in plants appears to be limitless from a scientific basis. However, today’s public sentiment does not support genetically modified organisms (GMOs). The agricultural community is being forced to find ways to show the public that genetic engineering is scientifically sound and environmentally safe.