Here is some quick info / summary of what I was referring to.
See some players in the game of biotech / GM seeds..DuPont etc.
Gene Flow: Scientific Summary and the DuPont Perspective Potential Impacts of Cross-Pollination Between Crop Varieties
Table of Contents
Introduction - Gene Flow Between Crop Varieties via Pollination Background: Factors Affecting Cross-Pollination Potential for Cross-Pollination and DuPont Product Development The Potential Impacts of Cross-Pollination Current DuPont Products and Potential Impacts of Cross Pollination Future Steps » More (FAQs)
1. Introduction - Gene Flow Between Crop Varieties via Pollination
Unintended cross-pollination of different cultivars of a crop can sometimes occur with commercially improved varieties, developed through conventional breeding or biotechnology, or landraces, which are locally adapted varieties derived from thousands of years of seed selection by farmers. A landrace typically grows in the same geographic region as its wild ancestor, and represents a genetic midway point in the development of modern, commercially improved varieties. As a result, much of the information in Gene Flow from Crops to Wild Relatives also applies to cultivated landraces.
For cross-pollination to occur, viable pollen from one variety must reach an unfertilized egg of another variety of the same crop. Many factors determine the likelihood of cross-pollination between two varieties, including:
tendency to self-fertilize, which commonly occurs in crops; whether corn pollen sheds from on variety at a time the other variety is receptive to it; crop pollen longevity, which can be minutes for some crops but hours for others; relative amounts of pollen produced by the varieties; how pollination of a crop occurs - via wind, insects or both; the physical proximity of the varieties to each other, which is of primary importance; and, weather » More Physical proximity of two varieties depends not only on the distance between cultivated fields but also on the inadvertent planting of a few seeds of one variety within a field of a different variety. Such inadvertent, but unavoidable, seed mixing can occur via a number of routes. For example, though seed companies invest significant resources trying to provide high variety purity, seeds purchased by farmers may contain trace amounts of seeds of a different variety. In addition, farmers can inadvertently mix seed varieties if they do not thoroughly clean planting equipment when they change varieties, or if their harvesting equipment misses a few seeds that can germinate during the next growing season.
Because government agencies recognize the inevitability of trace amounts of seed mixing and cross-pollination, national and international regulation of the seed and grain industries has always required a high standard for genetic purity of commercial seed batches and commodity grain shipments. » More
Finally, some cross-pollination between different cultivated varieties may not be unintentional. Studies have shown that indigenous farmers who save seed from year to year plant commercially improved seeds varieties with the intention of incorporating new genetic material into their local cultivars and landraces. » More
3. Potential for Cross-Pollination and DuPont Product Development
Following requirements, DuPont provides regulatory agencies information on the potential for cross-pollination. Because many crop-specific factors influence cross-pollination, assessing its likelihood requires separate analysis of each crop. To illustrate the value of this systematic, crop-by-crop approach, consider the biotech crops DuPont currently markets: corn, soybeans and canola.
Virtually no cross-pollination of commercial soybean varieties occurs between fields more than 30 feet apart. Cross-pollination in soy is a rare event because pollination usually occurs before the flower opens and becomes available for other pollen. Some studies have shown that insects can cause cross-pollination. Though a rare event, the rate of cross-pollination is higher between soybean plants of different variety when the varieties are grown within the same field. » More
Unlike soy, corn has a more open system of pollination. A corn plant can self-pollinate, but pollen from one plant can travel via wind to other, receptive corn plants. To determine the likelihood of cross-pollination between corn varieties, we assess information on relevant factors such as the amount of pollen produced by the two varieties; synchronicity of pollen shedding and receptivity of the two varieties; distance corn pollen can travel; and length of time corn pollen is viable. Recent research demonstrated one cross-pollination event (one kernel) in three of 12 cornfields surrounding a pollen source at 100m, 150m and 200m, but none in eight fields 300m and 400 m away. » More
The seed industry follows internationally determined and accepted standards for genetic purity. These standards call for the use of specific distances between fields to manage gene flow. These distances are necessary to meet the standards for purity.
The seed industry is applying the lessons learned from working with these standards, as well as our own experiences, to understand and manage gene flow issues related to crops derived through biotechnology. In addition to using isolation distances before marketing these crops, we surround the field with a number of border rows of non-biotech plants that serve as pollen-catchers. This reduces the chances for cross-pollination. In spite of the many measures (discussed below) we use during seed production to minimize the presence of biotech genetic material in non-biotech seed batches and vice versa, it is recognized by many that trace amounts of biotech genetic material or seeds may be found in some fields containing non-biotech varieties. » More
Pollination of oilseed Brassica crops, including canola, is primarily by insects, although pollen can also be wind-borne. Gene flow via pollination within or among cultivated Brassica species can occur at relatively high frequencies, especially when different varieties grow within the same field. However, gene flow between varieties grown in separated fields is reported to be very low, on the order of one to two seed in a thousand. In the case that canola acquires multiple herbicide resistance through cross-pollination, methods can be applied to control herbicide resistant varieties that have minimal or no impact on biodiversity. » More
4. The Potential Impacts of Cross-Pollination
The potential impacts of cross-pollination vary with the specific crop, whether it is a commercially improved variety or landrace; the grower's crop management practices; and the intended market for the crop.
There has been concern that genetic material from biotech crops could change some crops, such as canola and rice, into weed-like crops that are difficult to control. However in a ten-year study comparing four biotech and non-biotech crops, the new genetic material in biotech crops did not increase their ability to persist outside of cultivated agriculture settings. » More
The movement of a herbicide tolerance gene to a neighboring crop could have an impact on weed management in certain crop rotation systems whether the herbicide tolerance exists by biotech or conventional methods. In addition, tolerance to a broad-spectrum herbicide that farmers use for pre-planting elimination of volunteer crops and weeds could also increase the complexity of weed control. However, both impacts can be managed by using any of a number of other herbicides. » More
Cross-pollination between biotech and non-biotech varieties could have economic impacts if a farmer is a certified seed grower or is trying to serve a market that stipulates thresholds for biotech material. A 5% threshold can be attained readily for virtually all crops, and a 1-2% threshold is possible by using well-established and internationally accepted isolation distances. International regulatory agencies recognize a 0% threshold is impossible to consistently attain. » More
Finally cross-pollination could potentially have a negative impact on the long-term productivity of indigenous farmers if it decreased the genetic diversity of local cultivars and landraces. However, a number of studies provide evidence that indigenous farmers are increasing the diversity of their cultivars by incorporating the new genetic material provided by commercial varieties. » More
5. Current DuPont Products and Potential Impacts of Cross Pollination
DuPont currently markets three crop varieties developed using biotechnology: soybean and canola that are tolerant to the herbicide glyphosate; and corn that provides protection against specific insect larvae that feed on corn and against the herbicides glufosinate and glyphosate.
These products, sold under the Pioneer® brand, provide farmers with new crop management options and increased productivity. Before marketed, these products were rigorously tested and reviewed by regulatory authorities for food and feed safety, environmental impacts and product performance.
Neither corn nor soybeans exhibit characteristics that predispose them to weediness, therefore acquisition of new genes will not make these crops invasive in agricultural settings, in general. Nor will the specific acquisition of the herbicide tolerance gene in DuPont soybeans or canola create unmanageable weed control problems. If the glyphosate resistance gene transfers to non-biotech soy varieties, farmers can:
control volunteers, found growing unexpectedly in a crop rotation system, with a number of herbicides; and eliminate glyphosate resistant soy or canola prior to planting by using a different broad-spectrum herbicide in place of glyphosate. » More The economic impact that could result from cross-pollination of non-biotech soy, oilseed Brassica, and corn with DuPont biotech varieties should be minimal to non-existent if:
Regulatory agencies and commercial markets accept purity thresholds for biotech materials in non-biotech grain shipments that are equal to or less than those traditionally recommended by international agencies, such as 95 - 99%; and Farmers interested in serving those markets observe well-established, crop-specific isolation distances; plant non-biotech border rows; and follow other practices for minimizing on-farm seed mixing if they grow both biotech and non-biotech varieties. » More The potential of cross-pollination of biotech crops with landraces is possible only for soybeans growing in parts of China, Siberia, Taiwan, Korea Japan and Australia; and corn growing in Mexico, Central America and South America. Because of the tendency of soy landraces to self-pollinate, there will be little, if any, cross- pollination of glyphosate resistant soybeans to landraces. The possibility of cross-pollination is more likely with landraces of corn. Mexican farmers have intentionally cross-pollinated landraces with commercially improved, non-biotech varieties in order to give the locally-adapted cultivars desirable traits. Currently, however, in order to manage the incorporation of biotech materials into local cultivars, the Mexican government has placed a moratorium on the planting of biotech corn seeds. » More
6. Future Steps
Research is being done to determine effective methods for decreasing or preventing cross-pollination between biotech and non-biotech crops. Some involve non-technical solutions, such as increasing required isolation distances or using border rows of non-biotech crops to decrease the presence of biotech material. Others involve the use of biotechnology to manage gene flow. DuPont conducts research and participates in several industry-wide initiatives to better understand cross-pollination between crop varieties in order to minimize its occurrence. The American Seed Trade Association is compiling extensive information from past seed production seasons to determine the distance pollen from different crops travels and other factors related to cross pollination. An international project led by the Federation Internationale des Semeces in conjunction with the Organization for Economic Co-operation and Development (OECD) and International Seed Testing Association is conducting research on several fronts including standardizing the types of tests that are used to measure trace amounts of genetic material. The British Department for Environment, Food and Rural Affairs (DEFRA) has commissioned several studies that assess the potential impact of gene flow from biotech crops to non-biotech crops.
