In the mid-1860s, a geneticist named Gregor Mendel discovered the underlying mechanisms of genetic inheritance - including the notion of dominant and recessive genes - which furthered our understanding and subsequent application of genetic manipulation for agricultural purposes.
In the early 1930s, hybridization was developed, which allowed the artificial breeding of two distinct species to produce offspring that combined their characteristics. Prior to this time, selective breeding was only performed between individuals that were closely related or of the same species. The practice of hybridization is constrained by compatibility between the reproductive systems of the two species, but when successful it gives farmers new sources of potentially usable traits.
Since the 1970s, the laboratory techniques of agriculture biotechnology have allowed the use of targeted gene transfer to incorporate a single trait of one species into the genetic background of another.
Decisions on which methods are used to mix genes, which genes are retained in a single agricultural product, and how many different related varieties are maintained has an enormous impact on genetic and biological diversity at both the species and the regional level. All agricultural practices have both benefits and costs to individual species gene pools, biodiversity, the environment, and the economy. Discussed here are some of the major approaches to agriculture and a general summary of their potential impacts.
