When was plant breeding invented
To formalize the creation of new plant cultivars and plant breeding, Louis Leveque de Vilmorin, of the Vilmorin family of seed producers, founded the Vilmorin Breeding Institute in At the time, Vilmorin was working to lay the foundation for improved size, shape and sugar content of sugar beets. It was during this expedition that Darwin observed similarities among plant species all over the globe, along with variations based on specific locations.
Yet, biologists, botanists and plant scientists took note. At the turn of the century, three scientists were working on breeding problems and discovered a paper written decades earlier by Gregor Mendel.
First came the concept of crosses, which led to what is known as improved hybrid vigor in the early s. Mutation breeding was introduced in the s, according to the Food and Agriculture Organization of the United Nations. It can be used to accelerate the process of trait development and does not involve gene modification.
Furthermore, it broadens biodiversity. Around the world, plant breeders such as Norman Borlaug put their newfound knowledge to use, developing more productive, higher-yielding hybrids across a number of crop species including wheat and rice. The period from the s to s became known as the Green Revolution, when agricultural output significantly increased, saving billions of people from famine and starvation. Introduction to the Sorption of Chemical Constituents in Soils.
Pests and Pollinators. Soil erosion controls on biogeochemical cycling of carbon and nitrogen. The Influence of Soils on Human Health. Use and Impact of Bt Maize. Aquaculture: Challenges and Promise. Soil Carbon Storage. Soil Minerals and Plant Nutrition. Soil Water Dynamics. The Conservation of Cultivated Plants. The Soil Biota. Transgenic Animals in Agriculture. Citation: Wieczorek, A. Nature Education Knowledge 3 10 Aa Aa Aa.
Selective Cross Breeding. In traditional plant breeding, new varieties are developed either by selecting plants with desirable characteristics or by combining qualities from two closely related plants through selective breeding.
These features may for example be resistance to a particular pest or disease, or tolerance to climatic conditions. Pollen with the genes for a desired trait is transferred from plants of one crop variety to the flowers of another variety with other desirable traits.
Eventually, through careful selection of offspring, the desired trait will appear in a new variety of plants. Traditional plant breeding has produced numerous highly successful new varieties of crops over the centuries. There have also been many less than successful crosses made. In traditional breeding, crosses are often made in a relatively uncontrolled manner. The breeder chooses the parents to cross, but at the genetic level, the results are unpredictable. DNA from the parents recombines randomly, and desirable traits such as pest resistance may be bundled with undesirable traits, such as lower yield or poor quality.
The parent plants must be closely related to produce offspring. Traditional breeding programs are time-consuming, often taking decades to produce new viable crop varieties, and labor-intensive. A great deal of effort is required to separate undesirable from desirable traits, and this is not always economically practical.
Many potential benefits are lost along the way, as plants that fail to demonstrate the introduced characteristics are discarded. Traditional plant breeding takes on average years to produce a new crop variety. Classical Breeding with Induced Mutation. Genetic Engineering of Organisms. The basic structure of DNA is identical in all living things.
In all organisms, different characteristics are determined by the sequence of the DNA base pairs. Biotechnology has developed to the point where researchers can take one or more specific genes from nearly any organism, including plants, animals, bacteria, or viruses, and introduce those genes into the genome of another organism.
This is called recombinant DNA technology Watson et al. In , the first commercial product arising from the use of recombinant DNA technology gene transfer was synthetic insulin.
Pig and cattle pancreatic glands were previously the only way of producing insulin for human use. In , chymosin known as Rennin was the first enzyme produced from a genetically modified source-yeast-to be approved for use in food. Unfortunately modern crops are often susceptible to disease, insects, and abiotic stresses. To find resistance genes it is often necessary to go back to their wild ancestors and close relatives.
This is can be problematic due to the setback in yields attained when crossing to wild relatives, but it necessary for advancement of the crop. An understanding of crop domestication can help the plant breeder in her pursuit of the next best plant.
Early humans lived as hunter gatherers, victims of the wax and wane of the ecosystem in which they inhabited. For those that lived in grassland systems, a nomadic existence, following the plants and animals they fed upon was necessary. Tropical forest dwellers or those that lived in ecosystems where food was available year-round could build more permanent homes.
They all depended on that which sprang forth from the ground naturally for their sustenance however, which meant that their fates were not necessarily their own to choose. Survival was a full-time job. This inherent lack of control over their fates changed roughly 5, to 10, years ago with the domestication of the plant species that would become the first agricultural crops Smith and Pluciennik, The change did not occur abruptly Anderson, , and certainly did not resemble what we today would call agriculture for quite some time.
The domestication of the plant was arguably the single most important technological advance in our history, and allowed us to develop into the highly complex civilization we have become.
As technologically advanced as we might be, we are still as dependent on plants as we have ever been. It could be argued, that with the current population and rate of growth, we are more dependent on these crops than ever.
There were 6. Not only is that a lot of mouths to feed, but homes for 7 to 10 billion people covers large amounts of land. Much of that same land will be needed for food and fiber production.
It is interesting that the crops we grow globally today, to feed an ever growing society, in most cases were the same species our ancestors originally domesticated thousands of years ago. The beginnings of agriculture and plant domestication occurred at different times and places, with different plant species, for different societies around the globe Flannery, It appears that some societies did this independently of each other, and for other societies the technology was introduced.
An in-depth review of the archaeological evidence is beyond the scope of this chapter however, a discussion of plant domestication is impossible without an archaeological perspective. Plant Breeding Timeline. The exact mode of action is contentiously debated; however, Redding provides a useful generalized method. The proposed model involves the hunter-gatherer population for a given environment reaching the carrying capacity of the land and using methods to side-step the carrying capacity, either by avoidance or by directly increasing the capacity.
The inhabitants of the over-populated environment would have dealt with the lack of resources by 1 emigration, 2 reducing reproductive rate, 3 diversification, or 4 storage Redding, It is necessary to explain these methods clarified by Redding , as they are tantamount to the evolution of agriculture.
Emigration to a new environment with more available plants and animals to hunt is probably the easiest and most common method ancestral man used to escape the limited carrying capacity of a given environ. Diversification involved finding new sources of nutrition like a novel food plant or devising new technology to process an available resource not yet utilized for food, such as a mortar and pestle.
To decrease the uncertainty of the food supply, humans would have had to broaden their food choices and devise new methods to exploit novel sources Flannery et al. Storage could be considered a form of diversification, as it in many cases involves development of technology.
It is most likely the source from which agriculture evolved. Food storage could include capturing more animals than a group could consume immediately, and tying them up for later consumption.
It could also include the storage and carrying of edible seeds to eat later. The storage and transport of seeds could have easily led to planting the seeds for later harvest the next time the hunting-gathering group camped in the same area Redding, Any number of likely scenarios exists for the small leap from simply carrying around a few extra seeds for a later snack, to the conscious effort of saving some seeds to plant in a favorite tribal camping ground.
The small leap might have been spurred along by the rapidly changing climactic conditions of the late Pleistocene and early Holocene Richerson et al. As the earth warmed and glaciers receded the large land mammals became less numerous.
As the preferred nutrition of our hunter-gatherer forebears declined in numbers, human populations simultaneously increased. This increase in human population and decrease of such a vital resource caused the early humans to search for new resources and develop new behaviors Binford and Binford, ; Flannery et al. It is commonly held that agriculture arose at as many as nine different locations scattered around the globe, independently of each other.
It is from these centers that domesticated plants and agriculture first spread. The spread of this new technology would have been a slow process. It is unlikely that wholly nomadic peoples converted to sedentary agricultural systems over-night.
It is more likely that the transition was a slow one, involving both methods together for quite some time before finally settling down into a wholly agrarian existence Smith, a; Smith, b. These new methods and new plants would have spread faster going east or west across the globe from their origin. As was found to be the case in Africa, the spread north or south was more difficult due to climate adaptation Marshall and Hildebrand, Cohen et al. This could very well be the case for groups who were forced to switch from an entirely hunter-gatherer existence to an entirely agricultural existence due to lack of prey animals or some catastrophe.
The agricultural outputs would have struggled to catch up with necessity. In an experiment to test the difficulty of harvesting wild grains by hand, one researcher went to a naturally occurring stand of wild wheat in Turkey.
The limiting factor would be knowledge of which plants to taste or eat. Once the knowledge hurdle was crossed, the idea would have spread quickly within and without camps. The domestication of the plant and the subsequent development of agriculture allowed people to set down permanent roots and develop the rich cultures that led to our existence. With agriculture came the production of excess food and sedentary villages that were hitherto unobtainable.
The excess of food, and the decrease in time required to spend foraging, lead to a division of labor, the development of such things as art and science, and gave birth to modern civilization Diamond, Fortunately, more people could be sustained by a smaller land area with agriculture than before. Few plant species, of the thousands of possibilities, were ever domesticated for food, fiber, or other human use. His basic hypothesis is that these species were used for their ease of breeding for those traits that made them useful plants.
This idea is supported by a great deal of molecular work discussed later in this paper. This is interesting, and answers some very important questions. An example of this simple inheritance of important agricultural traits is the shattering system in wheat and barley. The mechanism by which wheat and barley scatter their seeds at maturity is controlled by a single gene.
When man selected for the non-shattering type wheat, the trait was fixed quickly and easily, making the crop preferable to others that might have been candidates Zohary and Hopf, It is obvious that our early ancestors would have preferred these cereals to all others simply because the grain stayed on the plant longer, and so the harvest window was longer than others. It seems that crop species were not necessarily selected, but serendipitously discovered because they did not need much tinkering to become valuable food sources and agricultural models.
The leap from useless weed to valuable food source was short and relatively easy. Almonds provide another example of simple inheritance of beneficial traits. The wild progenitors of almonds contained bitter chemicals to fend off predators, however, the mutation that makes the distasteful compounds absent is a single gene system and as such was easy to select.
Oak tree acorns, on the other hand, have similar distasteful compounds within them, but the trait is a polygenic trait, making selection difficult, especially for the unwitting plant breeders of antiquity, which might explain why oak trees have never been domesticated Diamond, Among the cultivated species, a certain set of traits exist that are common to nearly all of them.
It was originally postulated by Charles Darwin that differences seen in cultivated plants from their wild relatives was due to selection pressures by early man Darwin, ; Darwin, These are the traits that make the plants productive and beneficial to human society. The domestication syndrome traits imbued the crop plants with uniformity, predictability, and high productivity Table 1. There are several traits involved or contributing that include short stature rice, wheat , large fruit with tasty flesh tomatoes, apples , non-shattering rice, wheat, sorghum , reduced seed dormancy common beans , and reduced feeding deterrents virtually all.
These traits are summarized by Frary and Doganlar , and in the summary there is included a discussion on how few genes control each of these critical traits. There is no better example of how these traits can come together to produce something truly nutritive, than corn and its progenitor teosinte. Teosinte is a weedy looking grass with a small seed head made up of only two rows of several small, hard seeds. But somehow this wild and bushy bunch grass became the robust, single stalked behemoth we now know as field corn, whose constituents are used as ingredients in a plethora of food products consumed heartily by Americans daily.
The domestication traits would have been immensely important to the early agriculturalist, and rapidly fixed within their germplasm. It has also been shown by several researchers that many of these domestication traits are clustered near each other on the chromosome, and so are often closely linked Cai and Morishima, ; Khavkin and Coe, ; Koinange et al.
This clustering of domestication traits along the genome, and the small number of genes controlling these traits, suggest that the jump from wild, weedy progenitor might have occurred quite quickly, perhaps in as little as years Frary and Doganlar, This is of course hard to prove without archaeological evidence. It is evident that genetic diversity of our crops is much lower than that of their wild relatives.
Early farmers would have noticed these few mutants or deviants that exhibited a beneficial trait, kept them and planted them over and over again. This reduction of genetic diversity gave rise to what is known as the genetic bottleneck due to domestication. The bottleneck effect of domestication on the genetic diversity of crops was most likely due to small founder populations of the plants and strong selection pressures imposed upon these populations Iqbal et al. Plant domestication was arguably the single most important advancement in the history of mankind.
Once developed, agriculture spread across the globe like wild-fire. Our early ancestors unwittingly selected for traits that were easily fixed within the crop species, and as a product of their selection pressures, we now have reduced genetic diversity within our crops. Genetic bottlenecks have reduced the base of breeding materials available to the modern-day plant breeder.
Fortunately, however, we know of this short-coming, and have tools to combat it. We know the centers of origin for most crops and have the wild relatives to use as sources of diversity. There is much that can still be achieved through plant breeding of the crops and genetic resources we have.
As easy as it may be to complain and dwell on the lack of genetic diversity within our crops due to domestication. A discussion of plant domestication would be insufficient if it was not mentioned that our ancestors did an amazing job as amateur plant breeders.
For people who never had the opportunity to attend a plant breeding class, much less learn how to tie a shoe, they did quite a service for us.
Because of political situations, infrastructures, and distribution problems, millions of humans today still do not have either adequate or nutritional diets to sustain healthy lives, but in several cases adequate food supplies are available if properly used.
One example that illustrates how increased crop yields can contribute to increased populations will be given for U. Population of the United States increased from approximately 90 million citizens in to more than million in , i.
During the same time-frame, average U. Several factors have contributed to the increased grain yields. Optimistically, it seems further genetic progress can be sustained because as greater genetic information at the molecular level is understood and integrated with phenotypic selection, it will increase our effectiveness of selection. It will be essential that increased crop yields on a per unit area be continued in the future. The human and financial resource allocated to plant breeding research has had significant changes during the last half of the 20 th century Frey With the rediscovery of Mendelian genetics in , publicly supported researchers were in the forefront conducting basic research on the inheritance of traits and application of this information for cultivar development.
By year , significant changes in human and financial resources for plant breeding had been transposed from primarily the public sector to the private sector. Interest in the commercial potential of products derived from molecular studies delivered in plant cultivars dramatically increased the interests of private enterprise. Hence, private support for plant breeding increased very rapidly. By contrast resources dedicated to plant breeding in the public sector either significantly decreased or were transferred to the study of molecular genetics.
This dichotomy of resources for public and private research has transposed during the 20 th century because of the advances made in genetics and their value commercially. It seems this trend will continue in the future. The competitive nature of private enterprises will ensure that resources are made available to compete in the marketplace. Although the level of financial resources allocated to plant breeding has rapidly increased during the past 30 years, the investments have had favorable returns Crosbie et al.
Rapid progress also has been made in many nongenetic areas, such as plot equipment, computer systems for recording field data, field designs, statistical analyses, defining target environments, etc, have contributed significantly to increasing the efficiency of plant and progeny selection, or determining the breeding values for data taken at the phenotypic level Hallauer and Pandey Based on the past successes of plant breeders, it is my opinion that plant breeders will continue to have an important role to provide adequate and good quality field cultivars to meet our future needs.
Because greater genetic information has become available the art vs science of plant breeding has increased the relative importance to science. But, the phenotypes of the newer cultivars developed with greater emphasis on science will remain an important component of plant breeding. The great 17 th century French philosopher Rene Descartes made an interesting observation that applies to plant breeding: "emphasis on the application of scientific principles to practical everyday use.
Abrir menu Brasil. Crop Breeding and Applied Biotechnology. Abrir menu. Hallauer About the author. Key words : concepts of plant breeding, phenotypes, breeding values, genotypes. Maydica 55 : Bauman LF Review of methods used by breeders to develop superior corn inbreds. In 36 th Annual corn sorghum industry research conference , pp.
Coons GH Improvement of the sugar beet. In Yearbook of agriculture. USDA, U. Government Printing Office, Washington, D. Coors JG and Pandey S The genetics and exploitation of heterosis in crops American society of agronomy and crop science, Madison, p. Plant breeding: the Arnel R. Hallauer international symposium Blackwell Publishing, Ames, p. Dunn LC Mendel, his work and his place in history. In Proceedings of the American philosophical society , p.
Duvick DN Long-term selection in a commercial breeding program. In Janick J ed. Advanced Agronomy 86 : Maydica 46 : Fisher RA The correlation between relatives on the supposition of Mendelian inheritance. Transactions of the Royal Society of Edinburgh 52 : Frankel OH The dynamics of plant breeding. Journal of Australian Institute of Agriculture Science 24 : Iowa State University Special Report Gardner CO An evaluation of effects of mass selection and seed irradiation with thermal neutrons on yield of corn.
Crop Science 1 : Gepts P A comparison between crop domestication, classical plant breeding, and genetic engineering. Crop Science 42 : Johnson GR Marker-assisted selection. Hopkins G Improvements in the chemical composition of the corn kernel. Illinois Agriculture Experimental Station Bulletin 55 : Lee M The phenotypic and genotypic eras of plant breeding. Lonnquist JH A modification of the ear-to-row procedure for the improvement of maize populations.
Crop Science 4 : Marquez-Sanchez F A proposal to long term response to maize mass selection. Pixley KV Hybrid and open-pollinated varieties in modern agriculture. Hallauer international symposium Blackwell, Ames, p.
Iowa State University Press, Ames, p. Shull GH Hybridization methods in corn breeding. American Breeders Association Report 6 :
0コメント