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The geographic mosaic of herbicide resistance evolution in the common morning glory, Ipomoea purpurea: Evidence for resistance hotspots and low genetic differentiation across the landscape.

Kuester A, Chang SM, Baucom RS - Evol Appl (2015)

Bottom Line: We uncovered a mosaic pattern of resistance across the landscape, with some populations exhibiting high-survival postherbicide and other populations showing high death.SSR genotyping revealed little evidence of isolation by distance and very little neutral genetic structure associated with geography.An approximate Bayesian computation (ABC) analysis uncovered evidence for migration and admixture among populations before the widespread use of glyphosate rather than the very recent contemporary gene flow.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Evolutionary Biology, 830 North University, University of Michigan Ann Arbor, MI, USA.

ABSTRACT
Strong human-mediated selection via herbicide application in agroecosystems has repeatedly led to the evolution of resistance in weedy plants. Although resistance can occur among separate populations of a species across the landscape, the spatial scale of resistance in many weeds is often left unexamined. We assessed the potential that resistance to the herbicide glyphosate in the agricultural weed Ipomoea purpurea has evolved independently multiple times across its North American range. We examined both adaptive and neutral genetic variations in 44 populations of I. purpurea by pairing a replicated dose-response greenhouse experiment with SSR genotyping of experimental individuals. We uncovered a mosaic pattern of resistance across the landscape, with some populations exhibiting high-survival postherbicide and other populations showing high death. SSR genotyping revealed little evidence of isolation by distance and very little neutral genetic structure associated with geography. An approximate Bayesian computation (ABC) analysis uncovered evidence for migration and admixture among populations before the widespread use of glyphosate rather than the very recent contemporary gene flow. The pattern of adaptive and neutral genetic variations indicates that resistance in this mixed-mating weed species appears to have evolved in independent hotspots rather than through transmission of resistance alleles across the landscape.

No MeSH data available.


Related in: MedlinePlus

Ipomoea purpurea populations greater or less than the species' average of resistance at (A) 1.7 and (B) 3.4 kg a.i./ha. Horizontal dashed bars indicate the bootstrap estimates of the 95% confidence interval around the species' mean. Asterisks indicate populations that fall outside the 95% confidence interval.
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fig03: Ipomoea purpurea populations greater or less than the species' average of resistance at (A) 1.7 and (B) 3.4 kg a.i./ha. Horizontal dashed bars indicate the bootstrap estimates of the 95% confidence interval around the species' mean. Asterisks indicate populations that fall outside the 95% confidence interval.

Mentions: The overall species-level ED50 estimate for I. purpurea, based on survival, was 1.6 kg a.i./ha (95% CI: 1.12–2.10), which is similar to the manufacturer's recommended field dose of 1.54 kg a.i./ha. Twelve populations, all of which were from VA, SC, NC, and TN, exhibited a proportion survival that was significantly higher than the species average, that is, resistance values that were greater than the species 95% CI (Figs 1 and 3A). Nineteen populations fell significantly below the species average—12 of these were from the Southeastern USA (SC, NC, and TN) and seven were from the Midwestern USA (IN and OH) (Fig. 3A). Population-level ED50 estimates were considerably variable; however, overall, populations within the Southeastern USA, principally North Carolina and Tennessee, exhibited ED50 values above the species-level 95% CI, whereas populations in the Midwestern USA, mainly Ohio and Indiana, exhibited response levels below the average (Table S5) although the difference was not statistically significant.


The geographic mosaic of herbicide resistance evolution in the common morning glory, Ipomoea purpurea: Evidence for resistance hotspots and low genetic differentiation across the landscape.

Kuester A, Chang SM, Baucom RS - Evol Appl (2015)

Ipomoea purpurea populations greater or less than the species' average of resistance at (A) 1.7 and (B) 3.4 kg a.i./ha. Horizontal dashed bars indicate the bootstrap estimates of the 95% confidence interval around the species' mean. Asterisks indicate populations that fall outside the 95% confidence interval.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4561571&req=5

fig03: Ipomoea purpurea populations greater or less than the species' average of resistance at (A) 1.7 and (B) 3.4 kg a.i./ha. Horizontal dashed bars indicate the bootstrap estimates of the 95% confidence interval around the species' mean. Asterisks indicate populations that fall outside the 95% confidence interval.
Mentions: The overall species-level ED50 estimate for I. purpurea, based on survival, was 1.6 kg a.i./ha (95% CI: 1.12–2.10), which is similar to the manufacturer's recommended field dose of 1.54 kg a.i./ha. Twelve populations, all of which were from VA, SC, NC, and TN, exhibited a proportion survival that was significantly higher than the species average, that is, resistance values that were greater than the species 95% CI (Figs 1 and 3A). Nineteen populations fell significantly below the species average—12 of these were from the Southeastern USA (SC, NC, and TN) and seven were from the Midwestern USA (IN and OH) (Fig. 3A). Population-level ED50 estimates were considerably variable; however, overall, populations within the Southeastern USA, principally North Carolina and Tennessee, exhibited ED50 values above the species-level 95% CI, whereas populations in the Midwestern USA, mainly Ohio and Indiana, exhibited response levels below the average (Table S5) although the difference was not statistically significant.

Bottom Line: We uncovered a mosaic pattern of resistance across the landscape, with some populations exhibiting high-survival postherbicide and other populations showing high death.SSR genotyping revealed little evidence of isolation by distance and very little neutral genetic structure associated with geography.An approximate Bayesian computation (ABC) analysis uncovered evidence for migration and admixture among populations before the widespread use of glyphosate rather than the very recent contemporary gene flow.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Evolutionary Biology, 830 North University, University of Michigan Ann Arbor, MI, USA.

ABSTRACT
Strong human-mediated selection via herbicide application in agroecosystems has repeatedly led to the evolution of resistance in weedy plants. Although resistance can occur among separate populations of a species across the landscape, the spatial scale of resistance in many weeds is often left unexamined. We assessed the potential that resistance to the herbicide glyphosate in the agricultural weed Ipomoea purpurea has evolved independently multiple times across its North American range. We examined both adaptive and neutral genetic variations in 44 populations of I. purpurea by pairing a replicated dose-response greenhouse experiment with SSR genotyping of experimental individuals. We uncovered a mosaic pattern of resistance across the landscape, with some populations exhibiting high-survival postherbicide and other populations showing high death. SSR genotyping revealed little evidence of isolation by distance and very little neutral genetic structure associated with geography. An approximate Bayesian computation (ABC) analysis uncovered evidence for migration and admixture among populations before the widespread use of glyphosate rather than the very recent contemporary gene flow. The pattern of adaptive and neutral genetic variations indicates that resistance in this mixed-mating weed species appears to have evolved in independent hotspots rather than through transmission of resistance alleles across the landscape.

No MeSH data available.


Related in: MedlinePlus