Abstract
AbstractSeed shatter is an important weediness trait on which the efficacy of harvest weed seed control (HWSC) depends. The level of seed shatter in a species is likely influenced by agroecological and environmental factors. In 2016 and 2017, we assessed seed shatter of eight economically important grass weed species in soybean [Glycine max (L.) Merr.] from crop physiological maturity to 4 wk after maturity at multiple sites spread across 11 states in the southern, northern, and mid-Atlantic United States. From soybean maturity to 4 wk after maturity, cumulative percent seed shatter was lowest in the southern U.S. regions and increased moving north through the states. At soybean maturity, the percent of seed shatter ranged from 1% to 70%. That range had shifted to 5% to 100% (mean: 42%) by 25 d after soybean maturity. There were considerable differences in seed-shatter onset and rate of progression between sites and years in some species that could impact their susceptibility to HWSC. Our results suggest that many summer annual grass species are likely not ideal candidates for HWSC, although HWSC could substantially reduce their seed output during certain years.
Highlights
Grasses such as giant foxtail (Setaria faberi Herrm.), yellow foxtail [Setaria pumila (Poir.) Roem. & Schult.], and large crabgrass [Digitaria sanguinalis (L.) Scop.], each resistant to several herbicide sites of action (Heap 2019), are among the most common and problematic grass weeds in Downloaded from https://www.cambridge.org/core
We plotted spatial heat maps to visualize regional to continental patterns in the rates of combined grass weed seed shatter during the weeks following soybean maturity
As in our study of broadleaf weed phenology (Schwartz-Lazaro et al 2021), cumulative percent seed shatter was lowest in the southern U.S regions and increased moving north through the states (Figure 1)
Summary
Grasses such as giant foxtail (Setaria faberi Herrm.), yellow foxtail [Setaria pumila (Poir.) Roem. & Schult.], and large crabgrass [Digitaria sanguinalis (L.) Scop.], each resistant to several herbicide sites of action (Heap 2019), are among the most common and problematic grass weeds in Downloaded from https://www.cambridge.org/core. Plants of many annual weed species shatter seeds at crop maturity in the United States (Davis 2008; Norsworthy et al 2014; Schwartz-Lazaro et al 2017; Walsh et al 2018). Lower seed retention (41% at harvest, and 32% at 1 mo later) of E. crus-galli in soybean was reported from Arkansas (Schwartz-Lazaro et al 2017).
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.
