Along human history, more than 7000 plant species have been collected or cultivated by humans, but according to
Food and Ariculture Organization from the U.N. (F.A.O.) about a
95% of human caloric needs is provided by only 30 crops plants, and four of them are responsible for more than the 60% of human ingested calories (wheat, rice, maize and potatoes). In order to increase food production, it is important to understand how plant productivity can be improved.
Now scientists can use plant genetics to increase plant productivity and have an opportunity to fight world hunger. Here I am going to explain how crop plants production can be increased and which projects are being developed for this purpose. The image shows food from plants (Credits for the image:
Wikipedia, The Free Encyclopedia).
This post is divided into different parts. In the first part I want to motivate why we need to improve food plant production and I also try to put the historical context of crop plant research. In a second part I explain the current state of the art of plant research. Scientists are exploring many techniques to improve crop plants, at the same time that they try to preserve biodiversity. Finally I explain an international program that not only applies the newest technologies and research to crop plant production, but also makes the crops available to disadvantaged farmers in the developing world.
World Population
World Population has been growing at high rates (between 1,1% and 2,20%) in the last 100 years, with a peak in growth population rate in the 1960's, as can be seen in the World Population Prospects: 2008 revision from the U.N. The graphic below, also from the U.N. World Population Prospects show the expected increase of population from 1950 to 2050. It can be observed that, in spite of the slowing rate of growth, human world population could be in excess of 8 billion people by 2050 (Image source: Population growth. In Wikipedia, The Free Encyclopedia).
Green Revolution
David Hoisington, was the director of the Genetic Resources program at the CIMMYT (the Spanish acronym for the center of maize and wheat improvement). In his 1999 article, Plant genetic resources: What can they contribute toward increased crop productivity? published in the Proceedings of National Academy of Science (PNAS), he stated that the increasing of food demand without an increase of natural resources base is a great challenge. The article explains the perspectives of how plant genetics can help to fight hunger and gives some positive examples. Particularly it explains how the great increase of Mexico's wheat production was performed in 1940's. This increasing of wheat productivity was conceived at the CIMMYT and is considered the beginning of the Green Revolution.
The green revolution was a first attempt to use new technologies to increase food production and produced an increase of world grain production of 250% between 1950 and 1984. In 1943 most of the world were hungry and the vision of a Malthusian catastrophe was very extended. This means that many people believed that world population would grow exponentially and the agriculture production would not be sufficient to feed the world, producing famine. In Mexico, the government thought that the solution was in the technology and they created the CIMMYT. Using fungicides, fertilizers and plant breeding with Japanese dwarf wheat varieties, the wheat production in Mexico was multiplied and Mexico became a self-sufficient country.
The same scheme was then translated to India and some other Asia Countries with success. Africa did not benefit much from the green revolution, particularly because of the lack of irrigation. The methods of the Green revolution were criticized later by environmentalists but the truth is that the Green revolution helped to reduce the world hunger and Norman Borlaug, the father of the Green Revolution won the Nobel Peace prize in 1970 due to his contribution to the fight against world famine. The story of Norman Bourlag and Green revolution can be read in the John Pollock 2008 article in Technology Review, Green Revolutionary.
Plant Research
As a consequence of the Green revolution some centers were founded to investigate crop plants, as the CGIAR (Consultative Group on International Agriculture Research) research centers founded in 1970 to consolidate the achievements made in agriculture research. Main interests in the study of crop plants are genome sequencing, relation between genotype (the genetic constitution) and phenotype (the physical traits), and the preservation of biodiversity by means of plant gene banks.
Plant Genetics
The first crop plant genome completed was the rice genome. Two articles with the genome of two different varieties of rice, the indica and the Japanica, appeared in Science magazine in April 2002. The Indica variety was sequenced by Jun Yu of the Beijing Genomics Institute and the University of Washington Genome Center, with colleagues at 11 Chinese institution (A Draft Sequence of the Rice Genome (Oryza sativa L. ssp. indica) ). The Japanica variety was sequenced by a team led by Stephen Goff and colleagues at Syngenta (A Draft Sequence of the Rice Genome (Oryza sativa L. ssp. japonica) ). Other plant genomes are also being studied, the most important projects are the sequencing of wheat and barley.
Since man started to domesticate plants, they chose always the best adapted plants for their interests in order to increase productivity. Plant Breeding has been used since then to increase plant productivity. Of new techniques can be applied to plant breeding the best known is the creation of genetically modified organisms (GMO) crops, but the controversy about them made it expensive and difficult for public organisms to use this method.
In the article of Jorge Dubcovsky in Crop Science edition of November 2004, Marker-Assisted Selection in Public Breeding Programs: The Wheat Experience, he explains some applications of a new technique developed, the Marker assisted selection. It consists of the use of DNA tags to choose the variety with the traits of interest. The selection works not by choosing the trait directly, but by choosing the marker associated with it. An example of a marker, can be the morphological alteration of the interesting variety (colour, form, etc).
When traditional breeding is used to produce superior crops, many years may be needed in order to find the desired combination of genes, and the only way to know whether a plant has the desired gene or not is planting and waiting the plant to grow. The new techniques reduce the waiting time. But in order to use the marker assisted selection, the relationship between the phenotype, such as resistance to drought or resistance to some disease, and the genotype of crop plants must be well known. In the IPK, Institute of Plant Genetics and Crop Research, some projects are focused on this relationship, especially with crops wheat and barley.
Gene Banks and Conservation Biodiversity
When the best variety of a crop plant is planted on many fields, the region becomes a mono-culture and the biological diversity decreases. What happens if a new disease appears and the selected variety is not resistant to it? Or what if the field becomes more dry and the plant wasn't prepared for it?
The most logical way to find more varieties is going where wild crop grow, at the center of origins of that plant. Nikolai Vavilov, a Russian botanist and geneticist, established that there are only 8 centers of origin of the most important crop plants, as it can be seen in the figure below (source: Center of origin. In Wikipedia, The Free Encyclopedia.)
Recognizing the risk of loss of genetic variability, Vavilov started to collect plants in 1920, producing the first bank of plant genetic material. His theories of crop origin, cultivation and evolution are the scientific basis for the collection exploration and conservation of crop plants diversity. Andreas Börner, who published a review article in 2006 in the Biotechnology Journal, Preservation of plant genomics in biotechnology era, where - apart from Vavilov's theories - he explained how the seeds are conserved in gene banks. This is usually at -15ºC in dry conditions or at ultra-low temperatures when dry conditions are not possible. The most important Genebank is located in Germany, the IPK genebank, with more than 26000 collected samples.
Challenge Generation Program
The Consultative Group on International Agricultural Research, mentioned above, created a broad network of research centers and national agricultural research programs that work collectively in the Generation Challenge Program (GCP) not only to use research to obtain better crops, but also to made the improved crops available to disadvantaged farmers in tropic areas. The name of the program comes from Norman Bourlag, who at the launch of U.N. Millennium Development Goals in 2000 stated:
I challenge the next generation to use these new scientific tools and techniques to address the problems that plague the world’s poor.
The mission of the Generation Challenge program is to use genetic diversity to improve crops for greater food security in the developing world. The focus is on drought resistance, one of the main problems for farmers in the developing world. The program consists on five subprograms, where each one focuses on a different research. Currently the second subprogram is being developed, which puts the effort on the analysis and comparison of plant genomes in order to understand genes and non-coding regions function within the genome.
One of the most important funding agencies of the Generation Challenge Program is the European Comission who imposes as a condition for the funding not to use GMOs. Both, David Hoisington and Andreas Börner refer to genetic modification in their articles, coinciding in the opinion that GMOs are a faster way to produce better crops, not mentioning any safety problems. However there is a lot of public controversy about genetically modified food safety.
As we see in this post there are a lot of techniques to increase food production, to feed a growing population. Are they suficient? What is your opinion? famine, genetics, plants, politics, research, science
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