Competition for canopy cover between accessions of Phalaris minor that are susceptible and resistant to ACCase inhibiting herbicides

Abstract

Herbicide resistance has the potential to impose fitness costs in plants. In Mexico, Phalaris minor Retz. has evolved resistance to acetyl-coa carboxylase (ACCase) inhibiting herbicides. However, it is unknown whether these changes may involve other ecological costs for resistant individuals under non-selective conditions. The aim of this study was to determine whether the evolution of resistance has reduced the ability of P. minor to compete for resources at the seedling stage. De Wit's replacement series experiments (susceptible:resistant 100:0, 50:50, 0:100) were performed under two initial conditions. In the first experiment, we examined the effect of differences in germination time between resistant and susceptible genotypes on canopy cover. In the second experiment, germination was synchronized, and all the replacement series began at the same time. Delayed germination of resistant accessions reduced their ability to compete for canopy space, competition intensity index, and relative productivity in relation to susceptible accessions. When germination was synchronized, the resistant accessions had the same canopy cover and productivity as susceptible accessions. The delayed germination may cause displacement of resistant individuals in the absence of the selective factor (herbicide).

Herbicide Resistance in Phalaris Species: A Review

“…Due to the increased germination rate, the susceptible biotype had a greater canopy cover, competition intensity index, and relative productivity compared with the resistant biotypes. However, when the germination of resistant and susceptible biotypes was synchronized, the performance of the biotypes was similar [100].…”

Evolution, growth and phenology of Phalaris minor biotypes resistant to ACCase-inhibiting herbicides in Mexico

“…Furthermore, each resistant biotype might be locally adapted (life cycle and physiology) as a result of selection imposed by agricultural practices (Weinig 2005). For the biotypes present in this zone, some studies have shown differences in the early stages of plants life history, including changes in seed physiology (germination rate, dormancy and longevity) and growth for canopy competition (Torres-García et al 2015a, 2015b. In addition, empirical evidence based on morphology suggests differentiation among resistant weed populations (García-Franco et al 2014).…”

The pros and cons of being broad: recent and future progress of Nordic Journal of Botany

“…Still, we have recently published important contributions in these latter fields, e.g. Li et al () and Yousefi et al () on molecular phylogeny, Moradi et al () on spatial plant ecology, Torres‐García et al () on the evolutionary consequences of herbicide resistant plants, Paiva Farias et al () on tropical phenology and Tang et al () on molecular evolution in hybrids. We also know that many authors have found that the advantages of publishing with Nordic Journal of Botany, including a relatively fast review processes, rigorous editorial processing and editing of accepted manuscripts, advertising on social media, and Nordic Journal of Botany being society‐owned and run on a non‐profit basis, well compensate for the relatively low IF.…”