Roundup Ready Alfalfa: An Emerging Technology

Deynze, Allen Van; Putnam, Daniel H.; Orloff, Steve B.; Lanini, Tom; Canevari, Mick; Vargas, Ron; Hembree, Kurt J.; Mueller, Shannon; Teuber, Larry R.

doi:10.3733/ucanr.8153

Cited by 27 publications

(42 citation statements)

References 7 publications

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“…In this study, gene flow in flax was higher than reported for soybean, but lower than reported in similar scale experiments for wheat (Hanson et al, 2005), and safflower . In contrast, gene flow in the obligate outcrossing, insect-pollinated alfalfa (Medicago sativa L.) was detected as high as 0.2% at 1.5 km from the pollen source using a glyphosate-resistant trait (Van Deynze et al, 2004). When developing a GE crop, one factor to consider may be the proclivity for long-distance gene flow.…”

Section: Discussionmentioning

confidence: 94%

Pollen-mediated gene flow in flax (Linum usitatissimum L.): can genetically engineered and organic flax coexist?

et al. 2010

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Coexistence allows growers and consumers the choice of producing or purchasing conventional or organic crops with known standards for adventitious presence of genetically engineered (GE) seed. Flax (Linum usitatissimum L.) is multipurpose oilseed crop in which product diversity and utility could be enhanced for industrial, nutraceutical and pharmaceutical markets through genetic engineering. If GE flax were released commercially, pollen-mediated gene flow will determine in part whether GE flax could coexist without compromising other markets. ) to the low ALA trait. Seeds were harvested from the pollen recipient plots up to a distance of 50 m in eight directions from the pollen donor. High ALA seeds were identified using a thiobarbituric acid test and served as a marker for gene flow. Binomial distribution and power analysis were used to predict the minimum number of seeds statistically required to detect the frequency of gene flow at specific a (confidence interval) and power (1Àb) values. As a result of the low frequency of gene flow, approximately 4 million seeds were screened to derive accurate quantification. Frequency of gene flow was highest near the source: averaging 0.0185 at 0.1 m but declined rapidly with distance, 0.0013 and 0.00003 at 3 and 35 m, respectively. Gene flow was reduced to 50% (O 50 ) and 90% (O 90 ) between 0.85 to 2.64 m, and 5.68 to 17.56 m, respectively. No gene flow was detected at any site or year 435 m distance from the pollen source, suggesting that frequency of gene flow was p0.00003 (P ¼ 0.95). Although it is not possible to eliminate all adventitious presence caused by pollen-mediated gene flow, through harvest blending and the use of buffer zones between GE and conventional flax fields, it could be minimized. Managing other sources of adventitious presence including seed mixing and volunteer populations may be more problematic.

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Section: Discussionmentioning

confidence: 94%

Pollen-mediated gene flow in flax (Linum usitatissimum L.): can genetically engineered and organic flax coexist?

et al. 2010

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“…Several research-scale studies provide the scientific basis for the coexistence strategies developed and implemented by NAFA and AOSCA (Cornish et al, 2014;McCaslin and Van Deynze, 2014;Putnam et al, 2014;AOSCA, 2015). Fitzpatrick et al (2003) reported that with ALCB, transgene flow was 0.5% at 305 m, <0.2% at 457 m, and undetectable at 610 m. Teuber et al (2004) and Van Deynze et al (2004) reported that with HB, transgene flow decreased with distance, but they could still detect low levels (<0.03%) at 4 km. Teuber et al (2007) reported that when both HB and ALCB were used as pollinators, transgene flow was <0.2% at 1.6 km, <0.03% at 4.8 km, and nondetectable at 8.1 km.…”

Section: Isolation Distances For Transgenic Alfalfa Seedmentioning

confidence: 99%

Isolation Distances for Transgenic Alfalfa Seed Production in the Pacific Northwest

et al. 2019

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Alfalfa (Medicago sativa L.) was the first perennial crop genetically engineered (GE) to resist glyphosate herbicide. Since alfalfa is insect pollinated, the potential for transgene flow and occurrence of adventitious presence (AP) in conventional varieties is a concern, especially for organic and export producers. In response, the industry developed seed production isolation distances. However, no landscape‐scale studies have been conducted to validate industry standards. Our objective was to quantify the extent of gene movement from GE seed fields to commercial conventional seed fields on a landscape level to provide the industry with information to support coexistence strategies. Alfalfa seed fields were mapped in the Touchet area, Walla Walla Valley, Washington, during spring 2013. Fourteen conventional seed fields located at various distances from GE sources were identified, harvested, and tested for the presence of the GE trait. Although other variables affect gene flow, this article focuses on geographic distance, since this variable can be easily controlled by growers and industry. Using distance as the predictor variable, we modeled the relationship between AP proportion and distance to GE source fields at 0.1, 0.5, and 0.9% AP threshold levels using quadratic regression. As distance increased, transgene flow generally decreased. At a threshold level of 0.9% AP, an isolation distance of 330 m between conventional and GE fields is needed to ensure that at least 95% of the samples fall below this threshold level. Spatial prediction maps were consistent with our statistical analysis. At an average distance of 2.2 km, AP was 0.05%, and this decreased to 0.03% at an average distance of 8.8 km from GE seed fields.

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“…Alfalfa. Alfalfa is a perennial, mainly outcrossing, insectpollinated crop with no known compatible wild relatives in the United States (St. Amand et al 2000;Van Deynze et al 2004). However, feral alfalfa populations are common in areas where alfalfa is grown.…”

Section: Gene Flow From Herbicide-resistant Cropsmentioning

confidence: 99%

Herbicide Resistance: Toward an Understanding of Resistance Development and the Impact of Herbicide-Resistant Crops

Vencill¹,

Nichols²,

Webster³

et al. 2012

Weed sci.

256

196

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Development of herbicide-resistant crops has resulted in significant changes to agronomic practices, one of which is the adoption of effective, simple, low-risk, crop-production systems with less dependency on tillage and lower energy requirements. Overall, the changes have had a positive environmental effect by reducing soil erosion, the fuel use for tillage, and the number of herbicides with groundwater advisories as well as a slight reduction in the overall environmental impact quotient of herbicide use. However, herbicides exert a high selection pressure on weed populations, and density and diversity of weed communities change over time in response to herbicides and other control practices imposed on them. Repeated and intensive use of herbicides with the same mechanisms of action (MOA; the mechanism in the plant that the herbicide detrimentally affects so that the plant succumbs to the herbicide; e.g., inhibition of an enzyme that is vital to plant growth or the inability of a plant to metabolize the herbicide before it has done damage) can rapidly select for shifts to tolerant, difficult-to-control weeds and the evolution of herbicide-resistant weeds, especially in the absence of the concurrent use of herbicides with different mechanisms of action or the use of mechanical or cultural practices or both.

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Roundup Ready Alfalfa: An Emerging Technology

Cited by 27 publications

References 7 publications

Pollen-mediated gene flow in flax (Linum usitatissimum L.): can genetically engineered and organic flax coexist?

Pollen-mediated gene flow in flax (Linum usitatissimum L.): can genetically engineered and organic flax coexist?

Isolation Distances for Transgenic Alfalfa Seed Production in the Pacific Northwest

Herbicide Resistance: Toward an Understanding of Resistance Development and the Impact of Herbicide-Resistant Crops

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