Abstract
Abstract Italian ryegrass ( Lolium multiflorum L.) has become notorious due to glyphosate resistance evolution. To study the demography of susceptible and glyphosate-resistant Italian ryegrass populations, several experiments were conducted in the grower’s field to evaluate seedling emergence, survival and reproductive traits patterns in three cohorts, and the effect of density on seed production. Results showed that seedling emergence is fast, and under suitable environmental conditions, it can happen within 30-days. Lower plant survival was observed in the first two cohorts (2% and 3%, respectively) compared to the last (13%). A larger number of spikes (spk) per plant (pl) was observed in plants of the first two cohorts (50.34 and 47.02 spk pl-1, respectively) in comparison to the last one (26 spk pl-1); however, the third cohort presented a higher potential for flower (flwrs) production per spikelets (spklt) (13.5 flwrs spklt-1) in detriment to the first two (11.9 and 12.12 flwrs spklt-1). Fecundity was 20,300 and 13,830 seeds pl-1 for susceptible and glyphosate-resistant plants, respectively, and presented density-dependent regulation. A knowledge of Italian ryegrass’s demographic parameters provides valuable information for identifying particularly vulnerable life-history processes and developing population dynamics models that can contribute to designing more rational control strategies.
Highlights
Italian ryegrass (Lolium multiflorum Lam.) is an annual plant and a native of Southern Europe and currently distributed in temperate and humid subtropical climate regions worldwide (Terrel, 1968)
Italian ryegrass has evolved resistance to herbicides commonly used in winter cereal crops in Brazil, which increases the complexity of weed management in such crops
Seeds of the glyphosate-resistant Italian ryegrass population were collected from an area with a long history of herbicide resistance (> 15 years), and the glyphosatesusceptible Italian ryegrass population was harvested in an area close by < 2 km with a known history of susceptibility to glyphosate
Summary
Italian ryegrass (Lolium multiflorum Lam.) is an annual plant and a native of Southern Europe and currently distributed in temperate and humid subtropical climate regions worldwide (Terrel, 1968). Italian ryegrass has high biomass accumulation; it is used as forage production in integrated systems and as soil cover in conservation ones. As a weed, it is highly competitive, especially with winter cereals, and can reduce the wheat grain yield by up to 90% (Trusler et al, 2007). In Brazil, Italian ryegrass has evolved resistance to herbicide from three modes of action, including enolpyruvylshikimate-phosphate synthase (EPSPS), acetolactate synthase (ALS), and acetyl-CoA carboxylase (ACCase) inhibitor herbicides (Weed Science, 2020). Italian ryegrass has evolved resistance to herbicides commonly used in winter cereal crops in Brazil, which increases the complexity of weed management in such crops. A better understanding of weed biology can help identify the most vulnerable stages of the plant life cycle, adopting more efficient management strategies
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
