Limits...
Occurrence of an herbicide-resistant plant trait in agricultural field margins.

Gage KL, Gibson DJ, Young BG, Young JM, Matthews JL, Weller SC, Wilson RG - Ecol Evol (2015)

Bottom Line: We found that geographic location was an important factor in the occurrence of GR C. canadensis in field margins.Although not consistently associated with either glyphosate resistance or glyphosate susceptibility, there were differences in phenology, survivorship, and herbivory among biotypes of C. canadensis.We found equal or greater fitness in GR biotypes, compared to GS biotypes, and GR plants were present in field margins.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant, Soil, and Agricultural Systems Southern Illinois University Carbondale Illinois 62901 ; Department of Plant Biology Center for Ecology Southern Illinois University Carbondale Illinois 06460.

ABSTRACT
Agricultural environments allow study of evolutionary change in plants. An example of evolution within agroecological systems is the selection for resistance to the herbicide glyphosate within the weed, Conyza canadensis. Changes in survivorship and reproduction associated with the development of glyphosate resistance (GR) may impact fitness and influence the frequency of occurrence of the GR trait. We hypothesized that site characteristics and history would affect the occurrence of GR C. canadensis in field margins. We surveyed GR occurrence in field margins and asked whether there were correlations between GR occurrence and location, crop rotation, GR crop trait rotation, crop type, use of tillage, and the diversity of herbicides used. In a field experiment, we hypothesized that there would be no difference in fitness between GR and glyphosate-susceptible (GS) plants. We asked whether there were differences in survivorship, phenology, reproduction, and herbivory between 2 GR and 2 GS populations of C. canadensis in agrestal and ruderal habitats. We found that geographic location was an important factor in the occurrence of GR C. canadensis in field margins. Although not consistently associated with either glyphosate resistance or glyphosate susceptibility, there were differences in phenology, survivorship, and herbivory among biotypes of C. canadensis. We found equal or greater fitness in GR biotypes, compared to GS biotypes, and GR plants were present in field margins. Field margins or ruderal habitats may provide refugia for GR C. canadensis, allowing reproduction and further selection to occur as seeds recolonize the agrestal habitat. Agricultural practices may select for ecological changes that feed back into the evolution of plants in ruderal habitats.

No MeSH data available.


Related in: MedlinePlus

Occurrence of GR C. canadensis in 2008 field margins by USDA plant hardiness zone and management factors. (A) Principle component analysis (PCA) of data from spray test by field margin. USDA plant hardiness zones 4 and 5 were not different from each other (P = 0.38), but were different from 6 (P = 0.002, P = 0.004, respectively). (B) Mixed model analysis of discriminant analysis (DA) percent resistance for GR C. canadensis in 2008 field margins by USDA plant hardiness zone. (C) The relationship of occurrence of GR C. canadensis in 2008 field margins to tillage (no‐tillage or minimum/conventional tillage) in 2007. (D) The number of herbicide applications with mode of action (MOA) other than glyphosate for the field half managed according to grower practice (AG1) in 2007 by percentage of GR C. canadensis in 2008 field margins. Low herbicide diversity is 0 to 1 applications; high, 2 to 5 applications.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4588657&req=5

ece31667-fig-0002: Occurrence of GR C. canadensis in 2008 field margins by USDA plant hardiness zone and management factors. (A) Principle component analysis (PCA) of data from spray test by field margin. USDA plant hardiness zones 4 and 5 were not different from each other (P = 0.38), but were different from 6 (P = 0.002, P = 0.004, respectively). (B) Mixed model analysis of discriminant analysis (DA) percent resistance for GR C. canadensis in 2008 field margins by USDA plant hardiness zone. (C) The relationship of occurrence of GR C. canadensis in 2008 field margins to tillage (no‐tillage or minimum/conventional tillage) in 2007. (D) The number of herbicide applications with mode of action (MOA) other than glyphosate for the field half managed according to grower practice (AG1) in 2007 by percentage of GR C. canadensis in 2008 field margins. Low herbicide diversity is 0 to 1 applications; high, 2 to 5 applications.

Mentions: Plants were classified as GR or GS using PCA and DA. PCA axis 1 explained 81% of the variability in the data, while PCA axis 2 explained an additional 10% (data not shown). Parallel analysis (Franklin et al. 1995) determined that only PCA axis 1 scores should be retained for interpretation and further analysis, although axis 2 scores were used to produce scatter plots for visual examination (Fig. 2A). Component loadings for axis 1 indicated that visual ratings at 21 DAT and 14 DAT for the 1X rate treatment had the most influence on percentage of explained variability (Eigenvectors 0.52 and 0.50, respectively). In order of decreasing importance were 14 DAT 3X rate, 7 DAT 1X, 7 DAT 3X, and 21 DAT 3X (Eigenvectors 0.37, 0.35, 0.35, and 0.30). The least explanatory variables were the percentage of dry weight reductions for both 1X and 3X rates (Eigenvectors 0.004 and 0.002). By examining the placement of the known resistant and susceptible reference plants within the scatter plots, it was determined that a more negative score indicated a higher degree of herbicide resistance for mother plants as detected by the progeny spray tests (Fig. 2A).


Occurrence of an herbicide-resistant plant trait in agricultural field margins.

Gage KL, Gibson DJ, Young BG, Young JM, Matthews JL, Weller SC, Wilson RG - Ecol Evol (2015)

Occurrence of GR C. canadensis in 2008 field margins by USDA plant hardiness zone and management factors. (A) Principle component analysis (PCA) of data from spray test by field margin. USDA plant hardiness zones 4 and 5 were not different from each other (P = 0.38), but were different from 6 (P = 0.002, P = 0.004, respectively). (B) Mixed model analysis of discriminant analysis (DA) percent resistance for GR C. canadensis in 2008 field margins by USDA plant hardiness zone. (C) The relationship of occurrence of GR C. canadensis in 2008 field margins to tillage (no‐tillage or minimum/conventional tillage) in 2007. (D) The number of herbicide applications with mode of action (MOA) other than glyphosate for the field half managed according to grower practice (AG1) in 2007 by percentage of GR C. canadensis in 2008 field margins. Low herbicide diversity is 0 to 1 applications; high, 2 to 5 applications.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4588657&req=5

ece31667-fig-0002: Occurrence of GR C. canadensis in 2008 field margins by USDA plant hardiness zone and management factors. (A) Principle component analysis (PCA) of data from spray test by field margin. USDA plant hardiness zones 4 and 5 were not different from each other (P = 0.38), but were different from 6 (P = 0.002, P = 0.004, respectively). (B) Mixed model analysis of discriminant analysis (DA) percent resistance for GR C. canadensis in 2008 field margins by USDA plant hardiness zone. (C) The relationship of occurrence of GR C. canadensis in 2008 field margins to tillage (no‐tillage or minimum/conventional tillage) in 2007. (D) The number of herbicide applications with mode of action (MOA) other than glyphosate for the field half managed according to grower practice (AG1) in 2007 by percentage of GR C. canadensis in 2008 field margins. Low herbicide diversity is 0 to 1 applications; high, 2 to 5 applications.
Mentions: Plants were classified as GR or GS using PCA and DA. PCA axis 1 explained 81% of the variability in the data, while PCA axis 2 explained an additional 10% (data not shown). Parallel analysis (Franklin et al. 1995) determined that only PCA axis 1 scores should be retained for interpretation and further analysis, although axis 2 scores were used to produce scatter plots for visual examination (Fig. 2A). Component loadings for axis 1 indicated that visual ratings at 21 DAT and 14 DAT for the 1X rate treatment had the most influence on percentage of explained variability (Eigenvectors 0.52 and 0.50, respectively). In order of decreasing importance were 14 DAT 3X rate, 7 DAT 1X, 7 DAT 3X, and 21 DAT 3X (Eigenvectors 0.37, 0.35, 0.35, and 0.30). The least explanatory variables were the percentage of dry weight reductions for both 1X and 3X rates (Eigenvectors 0.004 and 0.002). By examining the placement of the known resistant and susceptible reference plants within the scatter plots, it was determined that a more negative score indicated a higher degree of herbicide resistance for mother plants as detected by the progeny spray tests (Fig. 2A).

Bottom Line: We found that geographic location was an important factor in the occurrence of GR C. canadensis in field margins.Although not consistently associated with either glyphosate resistance or glyphosate susceptibility, there were differences in phenology, survivorship, and herbivory among biotypes of C. canadensis.We found equal or greater fitness in GR biotypes, compared to GS biotypes, and GR plants were present in field margins.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant, Soil, and Agricultural Systems Southern Illinois University Carbondale Illinois 62901 ; Department of Plant Biology Center for Ecology Southern Illinois University Carbondale Illinois 06460.

ABSTRACT
Agricultural environments allow study of evolutionary change in plants. An example of evolution within agroecological systems is the selection for resistance to the herbicide glyphosate within the weed, Conyza canadensis. Changes in survivorship and reproduction associated with the development of glyphosate resistance (GR) may impact fitness and influence the frequency of occurrence of the GR trait. We hypothesized that site characteristics and history would affect the occurrence of GR C. canadensis in field margins. We surveyed GR occurrence in field margins and asked whether there were correlations between GR occurrence and location, crop rotation, GR crop trait rotation, crop type, use of tillage, and the diversity of herbicides used. In a field experiment, we hypothesized that there would be no difference in fitness between GR and glyphosate-susceptible (GS) plants. We asked whether there were differences in survivorship, phenology, reproduction, and herbivory between 2 GR and 2 GS populations of C. canadensis in agrestal and ruderal habitats. We found that geographic location was an important factor in the occurrence of GR C. canadensis in field margins. Although not consistently associated with either glyphosate resistance or glyphosate susceptibility, there were differences in phenology, survivorship, and herbivory among biotypes of C. canadensis. We found equal or greater fitness in GR biotypes, compared to GS biotypes, and GR plants were present in field margins. Field margins or ruderal habitats may provide refugia for GR C. canadensis, allowing reproduction and further selection to occur as seeds recolonize the agrestal habitat. Agricultural practices may select for ecological changes that feed back into the evolution of plants in ruderal habitats.

No MeSH data available.


Related in: MedlinePlus