History of Agricultural Biotechnology
History of Agricultural Biotechnology
History of Agricultural Biotechnology
has Evolved
By: Wieczorek Ania (Dept of Tropical Plant and Soil Sciences, University of Hi at Manoa) & Wright Mark (Dept of
Plant and Env Protection Sciences, University of Hi at Manoa) 2012 Nature Education
Have you ever wondered where our agricultural crops come from? And what were they like thousands of years ago, or
hundreds of years ago? Our food crops today are in fact very different from the original wild plants from which they were
derived.
About 10,000 years BC, people harvested their food from the natural biological diversity that surrounded them, and
eventually domesticated crops and animals. During the process of domestication, people began to select better plant
materials for propagation and animals for breeding, initially unwittingly, but ultimately with the intention of developing
improved food crops and livestock. Over thousands of years farmers selected for desirable traits in crops, and thus
improved the plants for agricultural purposes. Desirable traits included crop varieties (also known ascultivars, from
"cultivated varieties") with shortened growing seasons, increased resistance to diseases and pests, larger seeds and
fruits, nutritional content, shelf life, and better adaptation to diverse ecological conditions under which crops were grown.
Over the centuries, agricultural technology developed a broad spectrum of options for food, feed, and fiber production.
In many ways, technology reduces the amount of time we dedicate to basic activities like food production, and makes
our lives easier and more enjoyable. Everyone is familiar with how transportation has changed over time to be more
efficient and safer (Figure 1). Agriculture has also undergone tremendous changes, many of which have made food and
fiber production more efficient and safer (Figure 1). For example in 1870, the total population of the USA was
38,558,371 and 53% of this population was involved in farming; in 2000, the total population was 275,000,000 and only
1.8% of the population was involved in farming. There are negative aspects to having so few members of society
involved in agriculture, but this serves to illustrate how technological developments have reduced the need for basic
farm labor.
potential benefits are lost along the way, as plants that fail to demonstrate the introduced characteristics are discarded.
Traditional plant breeding takes on average 12-15 years to produce a new crop variety.
More than 2,500 plant varieties (including rice, wheat, grapefruit, lettuce and many fruits) have been developed using
radiation mutagenesis(FAO/IAEA, 2008). Induced mutation breeding was widely used in the United States during the
1970's, but today few varieties are produced using this technique. As our understanding of genetics developed, so new
technologies for plant variety development arose. Examples of these that are used today include genetic marker
assisted breeding, where molecular markers associated with specific traits could be used to direct breeding programs,
and genetic engineering. Some of the significant steps leading to the current state of the art are explained below.
1. Discovery by Watson and Crick: structure of DNA, 1953: Another milestone in the development of understanding of
genetics and how genes function, was the discovery of the structure of DNA (the basis of genes), and how DNA works.
Two scientists, James Watson and Francis Crick made this discovery (Pray 2008), considered to be one of the most
significant scientific works in biology, largely through synthesis of the work of other scientists. Their work contributed
significantly to understanding what genes were.
2. Discovering genes that move (transposons): Transposons are sections of DNA-genes-that move from one location
to another on achromosome. Transposons have been referred to as "jumping genes", genes that are able to move
around. Interestingly, transposons may be manipulated to alter the DNA inside living organisms. Barbara McLintock
(1950) discovered an interesting effect of transposons. She was able to show how the changes in DNA caused by
transposons affected the color of maize kernels.
3. Tissue culture and plant regeneration: Another significant development in technology that was important for plant
breeding was the development of micropropagation techniques, known as tissue culture (Thorpe 2007). Tissue culture
permits researchers to clone plant material by excising small amounts of tissue from plants of interest, and then
inducing growth of the tissue on media, to ultimately form a new plant. This new plant carries the entire genetic
information of the donor plant. Exact copies of a desired plant could thus be produced without depending on pollinators,
the need for seeds, and this could all be done quickly.
4. Embryo rescue: Often when distantly related plant species are hybridized are crossed, the embryos formed following
fertilization will be aborted. The development of embryo rescue technology permitted crop breeders to make crosses
among distantly related varieties, and then to save the resulting embryos and then grow them into whole plants through
tissue culture.
5. Protoplast fusion: Protoplasts are cells that have lost their cell walls. The cell wall can be removed either by
mechanical means, or by the action of enzymes. They are left with only a cell membrane surrounding the cell.
Protoplasts can be manipulated in many ways that can be used in plant breeding. This includes producing hybrid cells
(by means of cell fusion) and using protoplasts to introduce new genes into plant cells, which can then be grown using
tissue culture techniques (Thorpe 2007).
6. Genetic engineering: Building on the above discoveries into the 1980s, advances in the field of molecular biology
provided scientists with the potential to purposefully transfer DNA between organisms, whether closely or distantly
related. This set the stage for potentially extremely beneficial advancement in crop breeding, but has also been very
controversial.
The applications of genetic engineering through recombinant DNA technology increased with time, and the first small
scale field trials of genetically engineered plant varieties were planted and in the USA and Canada in 1990, followed by
the first commercial release of genetically engineered crops in 1992. Since that time, adoption of genetic engineered
plants by farmers has increased annually. While the benefits of genetically engineered crop varieties have been widely
recognized, there has been extensive opposition to this technology, from environmental perspectives, because of ethics
considerations, and people concerned with corporate control of crop varieties.