GMOs hybridizing with plants next to a field. (by Diego Fdez-Sevilla)
Bill Jewell said to me at LinkedIn: “I wonder if there is any research on GMOs hybridizing with plants next to a field where they are planted.”
So, this is my take on this.
First, I would suggest something like using three words in google “gmo” “cross” “pollination”. From there you have links to any kind of publications. If you are more interested in scientific approach you can select “academics” or “scholar” at the top of your results and you will access to articles related to your search.
As part of my take on the issue of “GMOs hybridizing with un-targetted plants”, there are some points I would like to highlight in here:
With other plants occurs and is a threat identified and recognised.
The following link exposes examples of GMOs hybridizing with plants next to a field where they were planted. This article covers also the implications for the farmers affected.
“GM Contamination Spreading. Contamination can occur in a number of different ways. Pollen drift from field to field via insects and wind is just the beginning.”
Gene flow creating the development of new traits in wild populations of un-targeted species such as resistance to Glyphosate also occurs and that is a threat identified and recognised.
Resistance to glyphosate has emerged in several different weed species. Such situation has direct implications in Agriculture but also in Health related issues since we can find among them various species of Ragweed (Ambrosia trifida and A. artemisiifolia). Ragweed is well known in Aerobiological studies by being one of the fastest spreading pollen types being main cause of allergy and pollen asthma in North America and Central Europe.
There are currently 461 unique cases (species x site of action) of herbicide resistant weeds globally, with 247 species (144 dicots and 103 monocots). Weeds have evolved resistance to 22 of the 25 known herbicide sites of action and to 157 different herbicides. Herbicide resistant weeds have been reported in 86 crops in 66 countries. You can see more on this at the International Survey of Herbicide Resistant Weeds web site:
Here I leave you also a link to an article published in 2012, addressing the posture adopted by seed producers over the issue of wild weeds adopting resistance to glyphosate. Back at the time only 20 different weed species were recognised to have developed resistance to glyphosate.
Points of view
As part of the topic I believe that it is important to represent as many points of view as possible.
In a discussion group at LnkedIn I raised the following related question:
Could be this resistance the result of gene transfer from GMO´s?
I received the following comment:
I suspect that gene transfer from GMOs as a common cause of herbicide resistance is a huge unsubstantiated leap. If one is trying to stir up controversy, that’s the way to do it. Pesticide resistance in plants is as old as the use of pesticides themselves. I don’t work with agronomic species (crops) but with ecological restoration and invasive species control nearly daily. We are constantly watching for herbicide resistance in target species. When this happens, it is common to switch to a herbicide with a different mode of action. Sometimes we switch prior to observing resistance so we don’t create that problem. Also, there are a lot of factors influencing the effectiveness of herbicides – growth stage of the target plant, temperature, and water availability to name a few. For example, one can literally soak Phragmites australis with herbicide just about any time of year without much effect. But time it just right, when the plant is bolting, and you get very good control. Similarly, apply herbicide to leafy spurge and get almost zero control unless you add methylated seed oil as a surfactant (other surfactants don’t seem to work). When one considers the possibility of naturally occurring pesticide-resistant individuals in a plant population and the results of natural selection when pesticides are used, and plant physiology and the various modes of action of herbicides, the complexities of weed science become apparent. Again, I think the claim that herbicide resistance is a result of gene transfer from GMOs is a stretch, to say the least.
Accordingly I replied:
I have raised the question about the part played by GMO´s in the equation for the development of resistance to glyphosate based in publications like this one:
“Gene flow from glyphosate-resistant crops.”
Pest Manag Sci. 2008 Apr;64(4):428-40. doi: 10.1002/ps.1517.
Gene flow from transgenic glyphosate-resistant crops can result in the adventitious presence of the transgene, which may negatively impact markets. Gene flow can also produce glyphosate-resistant plants that may interfere with weed management systems. The objective of this article is to review the gene flow literature as it pertains to glyphosate-resistant crops. Gene flow is a natural phenomenon not unique to transgenic crops and can occur via pollen, seed and, in some cases, vegetative propagules. Gene flow via pollen can occur in all crops, even those that are considered to be self-pollinated, because all have low levels of outcrossing. Gene flow via seed or vegetative propagules occurs when they are moved naturally or by humans during crop production and commercialization. There are many factors that influence gene flow; therefore, it is difficult to prevent or predict. Gene flow via pollen and seed from glyphosate-resistant canola and creeping bentgrass fields has been documented. The adventitious presence of the transgene responsible for glyphosate resistance has been found in commercial seed lots of canola, corn and soybeans. In general, the glyphosate-resistant trait is not considered to provide an ecological advantage. However, regulators should consider the examples of gene flow from glyphosate-resistant crops when formulating rules for the release of crops with traits that could negatively impact the environment or human health.
Comments ended here.
Wind pollinated crops are naturally designed to increase the chances of successful seed production by releasing vast amounts of pollen into the atmosphere in order to propagate the specie following evolutionary strategies. That means, producing more pollen they increase the chances to reach and fertilize more flowers producing more fruits, more seeds and more yield.
The implications of having to depend on such strategy to have a economic profitable yield implies no control or whatsoever into de behaviour of the pollen grains when they get airborne.
The appraisal to this question is based on a Gauss bell shape distribution pattern. So it assumes that the concentration of pollen released into the atmosphere decreases in distance from the release point in relation to the weight of the pollen grain type. So, Maize pollen as particle, is big and heavier than pollen from let’s say Oilseed, so the concentration of Maize pollen decreases in shorter distances than the same for Oilseed.
And this is true in conditions of wind absence and high atmospheric humidity conditions (pollen can take and release water getting heavier or lighter). But those plants using the atmosphere to transport their gene pool in order to produce the next generation of seeds are using those atmospheric conditions which augment the probability for the pollen released to move as further as possible, looking for increasing their geographic chances for pollination.
The atmospheric conditions that most suit this reproduction strategy (wind) are wind movement and low humidity. Those factors are necessary to enhance pollination success and can change enough between geographical areas to make invalid any standard defined by any trial under different geographical and atmospheric conditions. As an example, at the coastline there is a permanent current of air coming inland or from inland into the sea, due to convective currents, which already create a particular case study.
My thesis touched the implication of the aerodynamic properties of pollen grains in their atmospheric transport due to atmospheric conditions of wind speed and humidity, and the conclusion is that you can measure the distance that pollen grains of a particular plant can travel under defined atmospheric conditions but you cannot define if these conditions are going to be the ones in your field. (https://diegofdez-sevillagoogle.academia.edu/DiegoFdezSevilla)
Here I leave a paper by Martin Hoyle and James E. Cresswell (2007) talking about it.
The Effect of wind direction on cross-pollination in wind-pollinated GM crops. Ecological Applications 17:1234–1243. http://dx.doi.org/10.1890/06-0569
I hope it helps.