Transgenics Have Their Uses, but Aren’t a Panacea
February 10, 2011 Only a few years ago, transferring genes into cotton from another species was considered science fiction. Today, transgenic cotton is commonplace and is widely grown in many countries. By expanding the gene pool to other species, transgenic technology has made it possible to acquire traits that were otherwise not available.
Transgenic cottons have had very positive effects on cotton production and promise to continue to provide positive impacts. The two major transgenic types used today are the different forms of Bt genes for worm control and herbicide resistance (e.g., glyphosate resistance, commonly known as Round-up Ready®) genes to assist with weed control. Cottons possessing Bt genes immediately improved insect control and subsequently led to increased yields and lower insect control costs. Glyphosate-resistant cottons also profoundly affected cotton production systems in the United States. Use of glyphosate for over-the-top weed control simplified the process and decreased the time and effort needed to control weeds.
Consequently, growers increased their farm size while simultaneously reducing their per-unit production costs. Reducing the use of tillage and incorporated herbicides allowed cotton plants to develop better root systems and incur less damage. New forthcoming transgenics, including those for drought tolerance and reniform nematode resistance, should provide additional positive effects. Transgenes that might improve yield, lessen the stress on plants, and improve fiber quality are being sought, but they probably won’t be available any time in the near future.
Challenges to overcome
Unfortunately, there are negative effects associated with the adoption of transgenic cottons, as well. Technology fees associated with transgenes greatly increased the up-front investment, and subsequently some risks associated with a crop. From a legal perspective, transgenic cottons generated considerably more regulation.
From a breeding perspective, transgenic cultivars have been developed primarily using the backcross technique, which is a regression procedure that may restrict genetic advance of the germplasm.
The most recent concern with transgenes is increasing resistance. Most notably, the widespread use and misuse of glyphosate has led to the development of weeds with resistance to it; now at least 16 weed species worldwide have been confirmed resistant to glyphosate.
Some difficulties associated with transgenic cultivars have generated renewed interest in conventional cotton cultivars in parts of the United States. Certainly, transgenic technology will not be abandoned, but many growers simply want to have an alternative.
Several state experiment stations are addressing this issue by releasing competitive-yielding, high-fiber-quality conventional cultivars. These releases will also strengthen the basic genetic progress of cotton germplasm, which will in turn strengthen the cotton industry.
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