Intra- and interspecies competition of blackgrass and wheat in the context of herbicidal resistance and environmental conditions in Poland

Abstract

Blackgrass (Alopecurus myosuroides Huds.), one of the most aggressive grass weeds in Europe, is also a strong competitor of crops. This study aimed to assess the impact of environmental conditions on the competition between (1) ACC-ase and ALS herbicide-resistant (BR) and herbicide-susceptible (BS) blackgrass biotypes, (2) BR and winter wheat cv. Arkadia (W), and (3) BS and W. In the replacement series model, the experiment was conducted at seven sites across Poland during two seasons (2018/19 and 2019/20). In the BR-BS experiment, the BS biotype was in majority more competitive toward the BR biotype. However, in the regime of optimal hydrothermal conditions and at a higher sand content in the soil we observed a higher competitiveness of BR towards BS. The combined interactions between W and BR or BS were also affected by environmental conditions, i.e., soil texture and hydrothermal coefficient, as explained by PCA and k-means cluster analysis. At most sites, W was more competitive toward both BS and BR, which could result from earlier emergence of W in relation to B in majority of sites. Except for two cases, located on heavy, clay soils, during humid seasons, where B was more competitive toward W. We summarize that blackgrass competitiveness towards other biotypes and wheat depends to some extent on environmental conditions; however, the phenomenon should be explored in more detail.

Emergence and Phenological Development of Herbicide-Sensitive and Herbicide-Resistant Biotypes of Apera Spica-Venti and Winter Wheat under Competition

“…Still, its development rate increases significantly in spring, with an intensive biomass increase, and it can even outgrow the wheat crop before the earing stage, thus competing more strongly with it in later stages of development. Research by [52], in turn, indicates that the competitiveness of A. myosuroides against winter wheat depends largely on climatic conditions and the type of soil on which the test plants grow. Similar observations were made by [53], analyzing the competitiveness between winter wheat and Centaurea cyanus.…”

Competition between Winter Wheat and Cornflower (Centaurea cyanus L.) Resistant or Susceptible to Herbicides under Varying Environmental Conditions in Poland

“…However, the research on the competitiveness between wheat and herbicide-susceptible or resistant Apera spica-venti (silky bentgrass) [9] and Alopecurus myosuroides Huds. (blackgrass) [43] are available. During the wet season, wheat was more competitive with silky bentgrass or blackgrass biotypes, while under the dry season, the herbicide-resistant silky bentgrass biotype was more competitive in biomass accumulation.…”

“…In other studies [53], just as in our research, summer drought promoted the competitiveness of wheat over field poppy and field pansy. On the contrary, wheat has been shown to suppress these weeds, especially under wet years, for competition between WW and blackgrass [43] or silky bentgrass [9].…”

“…Arkadia (breeder: HR Danko PL). According to the replacement series competition model [9,43,44], the pot experiments were designed and conducted across Poland in situ at six different sites with varying physical and chemical soil properties in three replications everywhere and took place in the next three growing seasons. The first experiment was conducted in the 2017-2018 season at three different sites (Winna Góra, Swojczyce, and Wrocław), the second one during the 2018-2019 season at five sites (Lipnik, Czesławice, Swojczyce, Wrocław, and Mydlniki), and the third one (2019-2020) at two sites (Czesławice and Mydlniki) (Table 2).…”

“…In other studies, wheat generally suppressed herbicide-resistant and herbicide-susceptible Alopecurus myosuroides Huds. However, the authors showed that, on average, the susceptible (S) biotype was more competitive against the resistant (R) biotype [43].…”