What Causes Plant Hybridization?

Genetics

• Plant breeding works through genetics, the science of how individual organisms inherit certain traits. Genes govern plant characteristics and determine whether or not an offspring receives a certain trait from a parent. Whether the offspring receives a dominant or recessive gene from the parent plays a critical role. In a simple example, if the dominate gene is for large leaves, and the recessive gene is for small leaves, the offspring will bear large leaves if it receives a dominate gene from one or both parents. Only if it receives a recessive gene from both parents will it produce small leaves.

History

• Hybridization has a long history in agriculture. As far back as 10,000 years ago, people were selectively breeding plants for desirable characteristics. When a plant with the appropriate traits appeared, its seeds were kept and the favorable traits were passed down through succeeding generations. Gardeners produced hybrids down through the years, even though the principles behind hybridization were not fully comprehended until the experiments of the Austrian scientist Gregor Mendel in the mid-19th century provided the scientific foundation for understanding the process.

Vigor

• One positive result from plant breeding occurs when the offspring show greater hardiness, such as increased disease and insect resistance, than the parent plants, a phenomena called hybrid vigor. The offspring might also be larger and, in agricultural crops, produce better yields. Hybrid vigor plays a key role in creating new varieties of crops that improve on older strains. Hybrid vigor can fade when the offspring are crossed, so horticulturalists typically continue the parental lines and breed them to ensure the hybrids maintain their advantages.

Types

• The term hybridization refers both to breeding members of two different species and to crossing genetically diverse members of the same species. Hybrid plants of different genera or botanical families also exist, but remain rare. Hybrids occur naturally in addition to being created by artificial methods. For example, in areas called hybrid zones, plants with different traits cross-pollinate and produce hybrid offspring. The parent plants might be separate species or genetically diverse individuals of the same species.