~Hannah Sockel, Pine Bluff, Arkansas
A. Plant hybrids are produced when the pollen of one species or variety fertilizes the flower of a different species or variety, explains Christy Marsden, horticultural technician for education and outreach at Seed Savers Exchange in Decorah, Iowa. “Hybridization can occur naturally through random crosses,” Marsden adds, “but commercially available hybridized seed, often labeled as F1, is deliberately created from inbred lines to produce a uniform population of plants with certain traits.” These first-generation hybrids tend to grow better and produce higher yields than either of their parents due to a phenomenon called hybrid vigor, Marsden says. Seed produced by F1 plants is genetically variable, however, and may not yield plants that carry all of the desirable traits of the first-generation hybrids. “Not only will the plants be less uniform in appearance and quality, but they are often considerably less vigorous,” says Marsden. Gardeners who use hybrid plant varieties must purchase new seed every year to get plants with the qualities they desire.
The term variety refers to a population of plants that is genetically similar and has one or more traits that make it distinct from other plants of the same species. (Another commonly used term, cultivar, is applied to plant varieties that are produced by cultivation, or human intervention.)
Genetic engineering involves mechanically manipulating a plant’s genetic structure to give it a trait it doesn’t naturally possess or to limit expression of its natural characteristics. Genes from a bacterium or a fish may be inserted into a plant, for example, or specific genes may be suppressed. Plants resulting from genetic engineering are called genetically modified organisms, or GMOs. While plant breeders have long used genetic manipulation methods to produce plants with desirable characteristics, those techniques replicate the natural processes by which genetic information is remixed. By comparison, genetic engineering often results in a final product that could never be achieved by nature.
Image: (cc) Liz West/flickr
Ask Organic Gardening is edited by Deb Martin
Originally published in Organic Gardening magazine, April/May 2013