Hybrid plants are the result of cross-breeding similar varieties of parent plants. The goal is to produce desirable characteristics in the next generation, meaning that the hybrid seed will carry the newly combined and desirable genetic makeup. Plants have been doing this all by themselves for as long as they have been making seeds. Natural selection has allowed certain plant mutations to be forwarded to succeeding generations, establishing solid biodiversity. Hybridization techniques use the principles of natural selection in controlled plant breeding circumstances, allowing specific genetic crosses to be made. The resulting seed produces the hybrid generation. (Ref 3)
Gregor Mendel studied plant genetics in the 1860s. He experimented with peas, and tracked specific characteristics from generation to generation. His studies showed that characteristics could be controlled by using specific pollen with specific flowers to produce seeds that carried the desired characteristics. Although his work was not widely studied in his day, it became popular in the early 20th century when seed companies began experimenting with his ideas. Pioneer Hi-Breds of Des Moines, Iowa, was founded in 1926. Pioneer Hi-Bred scientists were the first to work on developing hybrid seed corn for large scale agriculture applications. Universities joined the research, and widespread commercial production of hybrid seeds with superior characteristics soon followed. (Ref 1)
Open-pollinated plants produce seeds that will grow true to type. Each succeeding generation of open pollinated plants will be closely similar to the preceeding generation. Open-pollination is achieved by wind, animals or insects mixing pollen from hundreds or even thousands of the same variety of plants. This creates a strong genetic diversity. It also creates an environment where the best genetic material is dominant, ensuring a successful future for the plant variety.
Hybrid plants grow from seeds which were created by purposely crossing two plants of the same variety with genetic differences. A hybrid is a controlled natural cross of pollen from one variety with a flower of a similar variety, with a viable seed result that will produce a new plant that carries the combined genetics of both parent plants. Plant hybridizers look for specific traits in the plants grown from this resulting seed, such as improved plant vigor and increased yield.
The first generation of a controlled cross is a simple hybrid, called an F-1 hybrid. When F-1 hybrid corn seeds are planted, for example, they will display the improved vigor, yield and other traits bred into them. If F-1 pollinates F-1, the resulting seeds, if planted, will revert to one of the original parent plants or a weaker inbred version. New F-1 seeds must be grown each year from the original parent plants. Seeds produced by two identical F1 hybrid plants are often sterile. This does not alter the fact that the F-1 hybrid seed produced vigorous, high-yielding plants with a healthy crop.
More complex hybridization techniques are used to combine characteristics from more than two parent plants. A simple illustration of this type of hybrid is a double-cross hybrid, which is created when four inbred parent plants are combined. Plants A and B result in seeds AB, and plants C and D result in seeds CD. When AB and CD are hybridized, the result is ABCD, a double cross hybrid.
Crops grown from F1 hybrid seeds have helped revolutionize US agricultural production for 100 years. Hybrid seed was a driving force in the agricultural improvements made by American farmers during the 20th century. However, modern plant genetics rely on biotechnology laboratory work and testing, not necessarily hybridization. This technology is referred to in different terms, most commonly as bio-engineered seed, or genetically modified seed. Bioengineering saves research time because it does not depend on the seasonal plant cycle to produce each generation of new seed to be crossed with the next. Bioengineered plants are created by splicing together genes to control specific characteristics. The splicing is done in a lab, and is not the result of pollination. Some bioengineering work uses genetic material from completely different organisms, splicing together plant, animal, bacteria and virus genes. Genetic modifications have created organisms with new genetic material that would never occur in nature.
Because they are the result of natural pollination, hybrid plants can safely improve crop production in developing countries by improving plant vigor and yield.
Genetically modified seeds are created in labs, with untested and unknown long term results. Several countries around the world question the safety of having bio-engineered crops in the food chain since the genes are manipulated unnaturally. Japan, Egypt and Ireland have banned genetically modified foods, and a growing number of countries continue to debate the ethical issues.