Modeling pollen-mediated gene flow from glyphosate-resistant to -susceptible giant ragweed (Ambrosia trifida L.) under field conditions

Abstract

A field experiment was conducted to quantify pollen mediated gene flow (PMGF) from glyphosate-resistant (GR) to glyphosate-susceptible (GS) giant ragweed under simulated field conditions using glyphosate resistance as a selective marker. Field experiments were conducted in a concentric design with the GR giant ragweed pollen source planted in the center and GS giant ragweed pollen receptors surrounding the center in eight directional blocks at specified distances (between 0.1 and 35 m in cardinal and ordinal directions; and additional 50 m for ordinal directions). Seeds of GS giant ragweed were harvested from the pollen receptor blocks and a total of 100,938 giant ragweed plants were screened with glyphosate applied at 2,520 g ae ha−1 and 16,813 plants confirmed resistant. The frequency of PMGF was fit to a double exponential decay model selected by information-theoretic criteria. The highest frequency of gene flow (0.43 to 0.60) was observed at ≤0.5 m from the pollen source and reduced rapidly with increasing distances; however, gene flow (0.03 to 0.04) was detected up to 50 m. The correlation between PMGF and wind parameters was inconsistent in magnitude, direction, and years.

Interspecific and intraspecific transference of metabolism‐based mesotrione resistance in dioecious weedy Amaranthus

“…Here, we accept our hypothesis as it was shown that under field research conditions mesotrione resistance alleles were transferred from R A. tuberculatus to S A. tuberculatus progeny through pollen. The frequency of gene flow was rapidly reduced within 45 m of the pollen source and varied with distance and direction, which was also documented with PMGF studies that used ALS (Liu et al ., ) and glyphosate resistance genes (Sosnoskie et al ., ; Ganie and Jhala, ; Sarangi et al ., ) in Amaranthus species. The mechanism of mesotrione resistance in R A. tuberculatus is herbicide detoxification via cytochrome P450 alleles (Oliveira et al ., 2018c).…”

Risk assessment of pollen‐mediated gene flow from Ga1‐m field corn to dent‐sterile Ga1‐s popcorn

“…Gene flow frequency follows a binomial distribution with two possible outcomes in this study: yellow kernels (gene flow occurred) and white kernels (no gene flow occurred). The probability of gene flow is a function of the covariate, distance from pollen donor (Ganie & Jhala, 2017; Sarangi et al., 2017). Distance from the pollen donor can take on any real value; however, the probability of gene flow ranges between 0 and 1.…”

“…A set of 564 possible models was constructed to explain the frequency of gene flow using an exponential decay function with distance from the pollen donor, direction of the pollen receptor relative to the pollen donor, average wind speed, wind frequency, wind direction, and/or maximum wind gust (Ganie & Jhala, 2017; Sarangi et al., 2017). Additionally, models were evaluated with and without thresholds of air temperature, relative humidity, and the dual threshold of air temperature and relative humidity.…”

“…The model with the lowest AICc and the highest AICw is considered the best explanation of the data within the model set (Anderson, 2007). The best model was evaluated for goodness of fit using Pearson's χ 2 test (Ganie & Jhala, 2017; Sarangi et al., 2017).…”

Spray particle drift mitigation using field corn (Zea mays L.) as a drift barrier

“…and a series of exponential decay models including wind parameters (speed, gust, and direction) were fitted to data for each nozzle × corn barrier combination using the gnm package in R Version 3.2.3 (R Foundation for Statistical Computing, Vienna, Austria). Akaike's information criterion (AIC) was used for the model selection, where the candidate model with the lowest AIC value was chosen to fit the data .…”