Fitness of ALS-Inhibitors Herbicide Resistant Population of Loose Silky Bentgrass (Apera spica-venti)

Abstract

Herbicide resistance is an example of plant evolution caused by an increased reliance on herbicides with few sites of action to manage weed populations. This micro-evolutionary process depends on fitness, therefore the assessment of fitness differences between susceptible and resistant populations are pivotal to establish management strategies. Loose silky bentgrass (Apera spica-venti) is a serious weed in Eastern, Northern, and Central Europe with an increasing number of herbicide resistant populations. This study examined the fitness and growth characteristics of an ALS resistant biotype. Fitness and growth characteristics were estimated by comparing seed germination, biomass, seed yield and time to key growth stages at four crop densities of winter wheat (0, 48, 96, and 192 plants m-2) in a target-neighborhood design. The resistant population germinated 9–20 growing degree days (GDD) earlier than the susceptible population at 10, 16, and 22°C. No differences were observed between resistant and susceptible populations in tiller number, biomass, time to stem elongation, time to first visible inflorescence and seed production. The resistant population reached the inflorescence emergence and flowering stages in less time by 383 and 196 GDD, respectively, at a crop density of 96 winter wheat plants m-2 with no differences registered at other densities. This study did not observe a fitness cost to herbicide resistance, as often hypothesized. Inversely, a correlation between non-target site resistance (NTSR), earlier germination and earlier flowering time which could be interpreted as fitness benefits as these plant characteristics could be exploited by modifying the timing and site of action of herbicide application to better control ALS NTSR populations of A. spica-venti.

Allelopathic influence of common buckwheat root residues on selected weed species

“…Some barnyard grass biotypes have evolved cross resistance to some herbicides, including imazamox, imazethapyr, and penoxsulam (Riar et al 2013). Wind grass (loose silky bentgrass) (Apera spica-venti L.) is an important weed in Europe with an increasing number of herbicide-resistant populations (Babineau et al 2017). Therefore, it is important to identify alternative methods to combat this weed.…”

Overexpression of AGAMOUS-like gene PfAG5 promotes early flowering in Polypogon fugax

“…For instance, in a glyphosate resistant population of Conyza bonariensis from Brazil, the rst oral bud formation was observed 28 days earlier than the glyphosate susceptible population [9]. An ALS resistant population of Apera spica-venti owered 13 days earlier than the susceptible population at a certain crop density [10]. Panicles of the ACCase herbicide resistant (due to the 2041 mutation) Hordeum glaucum biotype emerged approximately 20 days earlier than that of susceptible biotype in the eld [25].…”

“…Herbicide application is also a stress to weedy plants, and it can select for evolution of herbicide resistance [5]. Adaptive changes in seed germination and seedling emergence, ower bud formation and owering time have also been observed in herbicide resistant biotypes [6][7][8][9][10].…”

Ecological Evidence for the Fitness Trade-Off in Triazine Resistant Chenopodium Album L.: Can We Exploit the Cost of Resistance?

“…Fitness costs have been recorded in some cases of resistance to herbicides such as with Acetyl-CoA carboxylase (ACCase)-inhibitors [13], glyphosate [14], and dicamba [15]. However, in some cases of resistance to herbicides such as for acetolactate synthase (ALS)-inhibiting herbicides with a target-site resistance mechanism, no fitness costs have been found in resistant phenotypes [16]. Fitness costs in herbicide-resistant weeds can be manifested at different stages in the life history of affected plants, such as reduced germination and emergence, reduced growth and development, or reduced reproductive output [10].…”