Common Genetic Hybrid Plants

Genetic hybridizing has been an important part of agriculture since long before anyone had considered genetics or hybrids as distinct concepts. All endeavors to improve outcomes in crops through the combining of two or more strains of that crop demonstrate hybrid technology. However, recent scientific advances have made it easier to manipulate the outcomes of hybridizing in a laboratory environment, which has caused concern in a number of sectors for a number of reasons. Common genetic hybrid plants and the implications of hybridizing are considered here.

History

All interbreeding of plants conducted with the end of enjoying a combination of the parent plants' traits is a form of genetic hybridization, despite the fact that earlier farmers were unaware of the mechanism by which plants (and other organisms) transmitted hereditary information. For instance, most strains of modern wheat are derived from long-past hybridization. Other common hybrids that are widely accepted as quite normal plants include peppermint (a cross of spearmint and water mint) and the loganberry, a hybrid raspberry and blackberry. Hybrids of this type can be seen as an example of artificial selection, as opposed to natural selection, a process in which a plant or other organism's traits compete with others in the gene pool without human intervention.

Features

Hybrids, as an example of artificial selection, result from the selective breeding of desired characteristics. A plant that has been cultivated by humans is called a cultigen, in accordance with the practices of the International Symposium on the Taxonomy of Cultivated Plants. Plants that have become distinct and given their own names as a result of this selection are called cultivars. Several different types of hybrids can be seen, especially because the meaning of hybrid is so broad; these range from breeding together two purebred organisms, which creates a first filial (F1) generation; a hybrid of two of these is a double cross, and so forth. (For more on traditional hybrids, see "Resources" below.) There are also crosses between populations, such as the tangelo or loganberry, which are hybrids of distinctly different, variously related organisms. The term transgenic plants or GMOs (genetically modified organism) is normally reserved for plants that have been selectively bred using genetic technologies in a laboratory setting.

Types

Many common crops, such as wheat, corn and many flowers, are the results of hybridizing by crossing closely related organisms together selectively to obtain desired traits. For instance, seedless plants (like watermelons) have been selectively bred on the principle that polyploid plants are infertile, thus producing no seeds. Hybrids between species include the aforementioned peppermint, loganberry and tangelo, as well as crops like triticale (wheat and rye) and the limequat. Transgenic plants include well-known experiments into improving tomato characteristics, such as through the ultimately failed introduction of a fish gene, but also include more successful ventures like the integration of a gene into rice that allows it to make beta carotene. For more on transgenic plants, see the PBS Gallery of Genetic Modifications under "Resources."

Significance

Hybrids, no matter what their origin, are always designed to serve the population they feed better, whether through producing better yields or tastier crops. It is hoped that, with further work in transgenic hybrids, that plants can be found that can be shipped easier, kept longer, provide better tradition and have a decreased impact on soil chemistry.

Considerations

Many are concerned about the expansion of the use of transgenic hybrid crops, and are pushing governments and farmers to do more research and to clearly label all transgenic crops. Some countries have taken action to protect cisgenic (non-hybrid) crops and consumers, as many believe that not enough research has been done into the potential effects of the consumption of transgenic crops.