Читать книгу Principles of Plant Genetics and Breeding - George Acquaah - Страница 53

For as long as the world population is expected to continue to increase, there will continue to be a demand for more food. However, with an increasing population comes an increasing demand for land for residential, commercial, and recreational uses. Sometimes, farm lands are converted to other uses. Increased food production may be achieved by increasing production per unit area or bringing new lands into cultivation. Some of the ways in which society will affect and be affected by plant breeding in the future are as follows:

 New roles of plant breedingThe traditional roles of plant breeding (food, feed, fiber, and ornamentals) will continue to be important. However, new roles are gradually emerging for plants. The technology for using plants as bioreactors to produce pharmaceuticals will advance. The technology has been around for over a decade. Strategies are being perfected for use of plants to generate pharmaceutical antibodies, engineering antibody‐mediated pathogen resistance, and altering plant phenotype by immunomodulation. Successes that have been achieved include the incorporation of streptococcus surface antigen in tobacco, and the herpes simplex virus in soybean and rice.

 New tools for plant breedingNew tools will be developed for plant breeders, especially in the areas of the application of biotechnology to plant breeding (Table 1.4). New marker technologies continue to be developed and older ones advanced. Tools that will assist breeders to more effectively manipulate quantitative traits will be enhanced. Genomics and bioinformatics will continue to be influential in the approach of researchers to crop improvement. Marker‐assisted selection (MAS) will continue to be important in plant breeding in the twenty‐first century.

 The key players in the plant breeding industryThe last decade saw a fierce race by multinational pharmaceutical corporations to acquire seed companies. There were several key mergers as well. The modern technologies of plant breeding are concentrated in the hands of a few of these giant companies. The trend of acquisition and mergers are likely to continue in the future. Publicly supported breeding efforts will decline in favor of for‐profit programs.

 Yield gains of cropsWith the dwindling of arable land and the increasing policing of the environment by activists, there is an increasing need to produce more food or other crop products on the same piece of land in a more efficient and environmentally safer manner. High‐yield cultivars will continue to be developed, especially in crops that have received less attention from plant breeders. Breeding for adaptation to environmental stresses (e.g. drought, salt) will continue to be important, and will enable more food to be produced on marginal lands.

 The biotechnology debateIt is often said that these modern technologies for plant genetic manipulation benefit developing countries the most since they are in dire need of food, both in quantity and nutritional value. On the other hand, the intellectual property that covers those technologies is owned by giant multinational corporations. Efforts will continue to be made to negotiate fair use of these technologies. Appropriate technology transfers and support to these poor third world nations will continue, to enable them develop capacity for the exploitation of these modern technologies.

Table 1.4 Selected milestones in plant breeding.

9000 BCE	First evidence of plant domestication in the hills above the Tigris river.
3000 BCE	Domestication of all important food crops in the Old World completed.
1000 BCE	Domestication of all important food crops in the New World completed.
700 BCE	Assyrians and Babylonians hand pollinate date palm.
1694	Camerarius of Germany first to demonstrate sex in plants and suggested crossing as a method to obtain new plant types.
1716	Mather of USA observed natural crossing in maize.
1719	Fairchild created first artificial hybrid (Carnation × Sweet William).
1727	Vilmorin Company of France introduced the pedigree method of breeding.
1753	Linnaeus published “Species Plantarum.” Binomial nomenclature born.
1761–1766	Koelreuter of Germany demonstrated that hybrid offspring received traits from both parents and were intermediate in most traits; produced first scientific hybrid using tobacco.
1847	Reid's Yellow Dent maize developed.
1866	Mendel published his discoveries in “Experiments in plant hybridization,” cumulating in the formulation of laws of inheritance and discovery of unit factors (genes).
1899	Hopkins described the ear‐to‐row selection method of breeding in maize.
1900	Mendel's laws of heredity rediscovered independently by Correns of Germany, DeVries of Holland, and von Tschermak of Austria.
1903	Danish biologist Johannsen developed the pure‐line theory of selection.
1904–1905	Nilsson‐Ehle proposed the multiple factor explanation for inheritance of color in wheat pericarp.
1908–1909	Hardy of England and Weinberg of Germany developed the law of equilibrium of populations.
1908–1910	East published his work on inbreeding.
1909	Shull conducted extensive research to develop inbreds to produce hybrids.
1917	Jones developed first commercial hybrid maize.
1926	Pioneer Hi‐bred Corn Company established as first seed company.
1934	Dustin discovered colchicines.
1935	Vavilov published “The scientific basis of plant breeding.”
1940	Harlan used the bulk breeding selection method in breeding.
1944	Avery, MacLeod, and McCarty discovered DNA is hereditary material.
1945	Hull proposed recurrent selection method of breeding.
1950	McClintock discovered the Ac‐Ds system of transposable elements.
1953	Watson, Crick, and Wilkins proposed a model for the DNA structure.
1970	Borlaug received Nobel Prize for the Green Revolution.
Berg, Cohen, and Boyer introduced the recombinant DNA technology.
1994	FlavrSavr tomato developed as first GM food produced for the market.
1995	Bt corn developed.
1996	Roundup Ready soybeans introduced.
2004	Roundup Ready wheat developed.