As genetic fingerprinting began to develop in the 1990s, molecular breeding (using DNA markers in combination with phenotypic measures to drive the development of new crop varieties) resulted in increased yields despite the drought-inducing action of climate change. These techniques primarily involved transgenes, foreign DNA from other species that could be incorporated into the crop genome to provide insect and herbicide protection (1).
Biotechnology proved a major breakthrough in agricultural science, and its benefits would most likely touch your life on a daily basis. A general timeline of the major biotechnological advances in agriculture is summarised based on the review from Moose & Mumm, 2008 (2).
Early 1980s: First generation of transgenic plants, using Agrobacterium to transfer genes of interest to the plants.
Mid 1980s: Creation of genetic maps for agriculturally important crops, using genetic linkage between molecular markers and advantageous genes to drive crop traits of interest.
1996: Commercialisation of transgenic crops.
The impact of transgenic crops has been immense and widespread. ISAAA* estimate that between 1996-2010, biotechnology-enhanced crops enhanced food security, sustainability and climate change (3) by:
Increasing crop production, valued at US$78.4 billion
Providing a better environment, by saving 443 million kg (active ingredient) of pesticides
Reducing CO2 emissions by 19 billion kg in 2010 alone, equivalent to taking ~9 million cars off the road
Conserving biodiversity by saving 91 million hectares of land
Helping alleviate poverty by helping 15 million small farmers with their farming ventures
*(ISAAA=International Service for the Acquisition of Agri-biotech Applications – a not-for-profit international organisation sharing scientific knowledge of the benefits of crop biotechnology).
The success of biotech crops is also evidenced by the adoption and satisfaction from farmers, contributing to their growing utilisation.
The two most common crop modifications are:
- Bt crops – Bt corn, cotton, potatoes and many others have been genetically modified to express the crystal protein Cry3Bb1, an insecticide produced naturally by the bacteria Bacillus thuringiensis. BT modification has helped to drastically reduce crop damage by larvae of the European corn borer (Ostrinia nubilalis) or the corn rootworm beetle (Diabrotica spp.) (2)
- HT crops – Herbicide tolerant crops were developed by agricultural giant Monsanto as Roundup Ready®, referring to their tolerance to the active ingredient
in Roundup® herbicide, glyphosate. Glyphosate is a broad spectrum herbicide, due to its mechanism of action inhibiting the ubiquitous plant enzyme, EPSP (4).
In addition, the Hawaiian Rainbow papaya is the premier example of a plant genetically engineered to overcome the devastation of a specific viral outbreak: the Papaya ringspot virus (PRSV). You can read in more detail about the transgenic virus-resistant papaya here, or watch the documentary Food Evolution (with a 100% rotten tomatoes review score).
UP NEXT: However, while molecular breeding techniques were targeted towards traits controlled by a relatively simple pathway consisting of only a handful of genes, this was not possible for complex traits such as drought resistance. Next I will explore the confounding factors for traits underpinned by a complex genetic architecture, and the methods that are being developed to measure, understand and employ them.
(1) Hammer, G., Cooper, M., Tardieu, F., Welch, S., Walsh, B., van Eeuwijk, F., … Podlich, D. (2006). Models for navigating biological complexity in breeding improved crop plants. Trends in Plant Science, 11(12), 587–593. https://doi.org/10.1016/j.tplants.2006.10.006
(2) Moose, S. P., & Mumm, R. H. (2008). Molecular Plant Breeding as the Foundation for 21st Century Crop Improvement. Plant Physiology, 147(3), 969–977. https://doi.org/10.1104/pp.108.118232
(3) James, C. (2006). Global Status of Commercialized Biotech/GM Crops: 2011. International Service for the Acquisition of Agri-biotech Applications (Vol. 42). https://doi.org/10.1017/S0014479706343797
(4) P. Byrne. (2014). Genetically Modified ( GM ) Crops : Techniques and Applications. http://extension.colostate.edu/topic-areas/agriculture/genetically-modified-gm-crops-techniques-and-applications-0-710/