Pollen-mediated gene flow and transfer of resistance alleles from herbicide-resistant broadleaf weeds

Abstract

Pollen-mediated gene flow (PMGF) refers to the transfer of genetic information (alleles) from one plant to another compatible plant. With the evolution of herbicide-resistant (HR) weeds, PMGF plays an important role in the transfer of resistance alleles from HR to susceptible weeds; however, little attention is given to this topic. The objective of this paper was to review reproductive biology, PMGF studies, and interspecific hybridization as well as potential for herbicide resistance alleles to transfer in the economically important broadleaf weeds including common lambsquarters, giant ragweed, horseweed, kochia, Palmer amaranth, and waterhemp. The PMGF studies involving these species reveal that transfer of herbicide resistance alleles routinely occurs under field conditions and is influenced by several factors such as reproductive biology, environment, and production practices. Interspecific hybridization studies within Amaranthus and Ambrosia spp. show that herbicide resistance allele transfer is possible between species of the same genus, but at relatively low levels. The widespread occurrence of HR weed populations and high genetic diversity is at least partly due to PMGF, particularly in dioecious species such as Palmer amaranth and waterhemp compared with monoecious species such as common lambsquarters and horseweed. Prolific pollen production in giant ragweed contributes to PMGF. Kochia, a wind pollinated species can efficiently disseminate herbicide resistance alleles via both PMGF and tumbleweed seed dispersal, resulting in widespread occurrence of multiple HR kochia populations. The review conducted for the aforementioned species verifies that intraspecific and interspecific gene flow can occur, and even at a low rate, could contribute to the rapid spread of herbicide resistance alleles. Further research is needed to determine the role of PMGF in transferring multiple herbicide resistance alleles at the landscape level.

Effect of single or sequential POST herbicide applications on seed production and viability of glyphosate-resistant Palmer amaranth (Amaranthus palmeri) in dicamba- and glyphosate-resistant soybean

“…Klingaman and Oliver (1994) reported soybean-yield losses of 17%-68% with Palmer amaranth density of 0.33-10 plants m −2 in Arkansas. Palmer amaranth is a dioecious species (i.e., male and female plants are separate), which results in wide genetic diversity, due to pollen-mediated gene flow (Oliveira et al 2018) and rapid spread of herbicide-resistance alleles (Jhala et al 2021).…”

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AJ (2021) Effect of single or sequential POST herbicide applications on seed production and viability of glyphosate-resistant Palmer amaranth (Amaranthus palmeri) in dicamba-and glyphosate-resistant soybean.

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Biologically-Effective-Dose of Tolpyralate and Tolpyralate plus Atrazine for Control of Multiple-Herbicide-Resistant Waterhemp [<i>Amaranthus tuberculatus</i> (Moq.) J. D. Sauer] in Corn

“…Additionally, 80% of these populations have three-way multiple resistance to ALS-, PS II-, and EPSPS-inhibitors. The dioecious and anemophilous biology, coupled with the potential for pollen-mediated gene flow in waterhemp enables transfer of herbicide resistance alleles among populations [16], further complicating manage-ment of this species with herbicides [12] [17].…”

Emergence pattern of Palmer amaranth (Amaranthus palmeri) influenced by tillage timings and residual herbicides

“…In addition, a widespread occurrence of atrazine, ALS inhibitors, and/or glyphosate-resistant Palmer amaranth in several counties in south-central Nebraska is challenging for corn and soybean growers (Jhala et al 2014). Palmer amaranth's dioecious nature provides an opportunity to spread herbicideresistance alleles from herbicide-resistant males to susceptible female plants via pollen-mediated gene flow (Jhala et al 2020;Sosnoskie et al 2012).…”