A review of transgenic crops resistance to herbicides: benefits and disadvantages

Biotechnology has the potential to bring many benefits to crop production. However, the use of this technology needs to be implemented with caution to avoid that possible risks cause problems to farm production and productivity. So far, the main traits that are commercialized with biotech crops in many parts of the world are herbicide or insect resistance. The fact is that major genes control these characteristics and international companies can easily profit from this technology. Many other traits can have benefits to crop production, including: drought resistance, improved nitrogen use, increased crop yield, increased grain quality, among others. However, most of these traits do not have genes with a universal expression, which increases the liability for companies to develop them. Alternatively, some of these traits are not easily recognized by the farms as worth for the extra technology fee that is charged with the seeds. Therefore, it is reasonable to conclude that these traits should be developed by the public sector in order to become available to the public at no extra cost. It was possible to demonstrate many benefits were attained by the farmers. But, many growers also were aware of the risks involved in the technology and preferred to adopt it with caution. Only a small fraction of the problems are perceived by the farmers, which may explain why they are very slow to avoid the risks and to prevent the problems. The fact that a crop is resistance to a herbicide do not imply that this crop-herbicide can be used as the only strategy for weed control. In reality, it is necessary to use many approaches in order to achieve long term weed control. Among the techniques recommended it is included: crop rotation, rotation of herbicides with different mechanisms of action, integration of methods of weed control, equipment cleaning to minimize the dispersion of resistant and tolerant weed species, among others. In summary, the good and old agronomic practices are still necessary to achieve optimum crop productivity during many years.