Plant breeding started with sedentary agriculture, particularly the domestication of the first agricultural plants, a practice which is estimated to date back 9,000 to 11,000 years. Initially, early human farmers selected food plants with particular desirable characteristics and used these as a seed source for subsequent generations, resulting in an accumulation of characteristics over time. In time however, experiments began with deliberate hybridization, the science and understanding of which was greatly enhanced by the work of Gregor Mendel. Mendel's work ultimately led to the new science of genetics. Modern plant breeding is applied genetics, but its scientific basis is broader, covering molecular biology, cytology, systematics, physiology, pathology, entomology, chemistry, and statistics (biometrics). It has also developed its own technology. Plant breeding efforts are divided into a number of different historical landmarks.
Early plant breeding
Domestication
Domestication of plants is an artificial selection process conducted by humans to produce plants that have more desirable traits than wild plants, and which renders them dependent on artificial usually enhanced environments for their continued existence. The practice is estimated to date back 9,000-11,000 years. Many crops in present-day cultivation are the result of domestication in ancient times, about 5,000 years ago in the Old World and 3,000 years ago in the New World. In the Neolithic period, domestication took a minimum of 1,000 years and a maximum of 7,000 years. Today, all principal food crops come from domesticated varieties. Almost all the domesticated plants used today for food and agriculture were domesticated in the centers of origin. In these centers there is still a great diversity of closely related wild plants, so-called crop wild relatives, that can also be used for improving modern cultivars by plant breeding.
A plant whose origin or selection is due primarily to intentional human activity is called a cultigen, and a cultivated crop species that has evolved from wild populations due to selective pressures from traditional farmers is called a landrace. Landraces, which can be the result of natural forces or domestication, are plants or animals that are suited to a particular region or environment.
In some cases, such as rice, different subspecies were domesticated in different regions; Oryza sativa subspecies indica was domesticated in South Asia, while Oryza sativa subspecies japonica was developed in China.
For more on the mechanisms of domestication, see Hybrid (biology).
Columbian Exchange
Humans have traded useful plants from distant lands for centuries, and plant hunters have been sent to bring plants back for cultivation. Human agriculture has had two important results: the plants most favoured by humans came to be grown in many places and (2) gardens and farms have provided some opportunities for plants to interbreed that would not have been possible for their wild ancestors. Columbus's arrival in America in 1492 triggered unprecedented transfer of plant resources between Europe and the New World.
Scientific plant breeding
Thomas Fairchild (? 166710 October 1729) was an English gardener, "the leading nurseryman of his day", working in London. He corresponded with Carl Linnæus, and helped by experiments to establish the existence of sex in plants. In 1716-17 (the cross made in summer 1716, the new plant appearing the next spring) he was the first person to scientifically produce an artificial hybrid, Dianthus Caryophyllus barbatus, known as "Fairchild's Mule", a cross between a Sweet william and a Carnation pink.
Gregor Mendel's experiments with plant hybridization led to his laws of inheritance. This work became well known in the 1900s and formed the basis of the new science of genetics, which stimulated research by many plant scientists dedicated to improving crop production through plant breeding.
However, successful commercial plant breeding concerns began to be founded from the late 19th century. Gartons Agricultural Plant Breeders in England was established in the 1890s by John Garton, who was one of the first to cross-pollinate agricultural plants and commercialize the newly created varieties. He began experimenting with the artificial cross pollination firstly of cereal plants, then herbage species and root crops and developed far reaching techniques in plant breeding.
William Farrer revolutionized wheat farming in Australia with the widespread release in 1903 of the fungus resistant "Federation" strain of wheat, which was developed as a result of his plant breeding work over a period of twenty years using Mendel's theories.