Rice cultivar tolerance to preemergence- and postemergence-applied fluridone

Fluridone was registered for use in rice production in 2023, offering a new herbicide site of action for growers. However, little information is available on the degree of rice tolerance to this herbicide. Field experiments conducted in 2022 and replicated in 2023 near Colt, AR, evaluated the tolera...

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Main Authors: Maria C.C.R. Souza, Jason K. Norsworthy, Pâmela Carvalho-Moore, Amar Godar, Samuel B. Fernandes, Thomas R. Butts
Format: Article
Language:English
Published: Cambridge University Press 2025-01-01
Series:Weed Technology
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Online Access:https://www.cambridge.org/core/product/identifier/S0890037X25000132/type/journal_article
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author Maria C.C.R. Souza
Jason K. Norsworthy
Pâmela Carvalho-Moore
Amar Godar
Samuel B. Fernandes
Thomas R. Butts
author_facet Maria C.C.R. Souza
Jason K. Norsworthy
Pâmela Carvalho-Moore
Amar Godar
Samuel B. Fernandes
Thomas R. Butts
author_sort Maria C.C.R. Souza
collection DOAJ
description Fluridone was registered for use in rice production in 2023, offering a new herbicide site of action for growers. However, little information is available on the degree of rice tolerance to this herbicide. Field experiments conducted in 2022 and replicated in 2023 near Colt, AR, evaluated the tolerance of 12 rice cultivars to fluridone, applied preemergence or at the 3-leaf growth stage, in separate experiments. Each experiment consisted of one cultivar. Fluridone rates included 0, 168 (1 × label rate), and 336 (2 × label rate) g ai ha−1 in all experiments. Visible injury varied between years in all experiments, likely due to different environmental conditions. In 2022, injury following preemergence applications of fluridone was below 25% across cultivars. In contrast, in 2023, injury ≥30% occurred to five cultivars, with a maximum of 58% observed for the cultivar ‘DG263L’. In both years, only three cultivars exhibited injury ≥20% following fluridone applications at the 3-leaf stage. Fluridone negatively affected shoot density, groundcover, chlorophyll content, and days to 50% heading in most cultivars when applied preemergence. When fluridone was applied to 3-leaf rice, at least one of the variables evaluated was negatively affected in two and nine cultivars in 2022 and 2023, respectively. Grain yield reductions of at least 18% were observed from eight cultivars in 2022, and a grain yield decrease from 9% to 49% from eight cultivars occurred in 2023 in the preemergence experiments. Fluridone applied to rice at the 3-leaf stage did not cause a yield penalty to any cultivar in 2022, whereas in 2023, a yield loss occurred from eight cultivars. Yield loss from the DG263L cultivar occurred at the 1 × rate in both experiments, indicating that this cultivar appears to be sensitive to fluridone, regardless of the application timing. Based on these findings, fluridone tolerance is cultivar-dependent. Furthermore, preemergence applications of fluridone to rice should be avoided.
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spelling doaj-art-d375d5c20c2e4bc68a996246a5e600c92025-08-20T03:58:40ZengCambridge University PressWeed Technology0890-037X1550-27402025-01-013910.1017/wet.2025.13Rice cultivar tolerance to preemergence- and postemergence-applied fluridoneMaria C.C.R. Souza0https://orcid.org/0000-0002-9378-9586Jason K. Norsworthy1https://orcid.org/0000-0002-7379-6201Pâmela Carvalho-Moore2https://orcid.org/0000-0002-4832-9062Amar Godar3https://orcid.org/0000-0001-9980-6562Samuel B. Fernandes4https://orcid.org/0000-0001-8269-535XThomas R. Butts5https://orcid.org/0000-0001-8310-0493Graduate Research Assistant, Department of Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville, AR, USADistinguished Professor, Department of Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville, AR, USAGraduate Research Assistant, Department of Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville, AR, USAPost Doctoral Fellow, Department of Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville, AR, USAAssistant Professor, Department of Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville, AR, USAClinical Assistant Professor, Extension Weed Scientist, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USAFluridone was registered for use in rice production in 2023, offering a new herbicide site of action for growers. However, little information is available on the degree of rice tolerance to this herbicide. Field experiments conducted in 2022 and replicated in 2023 near Colt, AR, evaluated the tolerance of 12 rice cultivars to fluridone, applied preemergence or at the 3-leaf growth stage, in separate experiments. Each experiment consisted of one cultivar. Fluridone rates included 0, 168 (1 × label rate), and 336 (2 × label rate) g ai ha−1 in all experiments. Visible injury varied between years in all experiments, likely due to different environmental conditions. In 2022, injury following preemergence applications of fluridone was below 25% across cultivars. In contrast, in 2023, injury ≥30% occurred to five cultivars, with a maximum of 58% observed for the cultivar ‘DG263L’. In both years, only three cultivars exhibited injury ≥20% following fluridone applications at the 3-leaf stage. Fluridone negatively affected shoot density, groundcover, chlorophyll content, and days to 50% heading in most cultivars when applied preemergence. When fluridone was applied to 3-leaf rice, at least one of the variables evaluated was negatively affected in two and nine cultivars in 2022 and 2023, respectively. Grain yield reductions of at least 18% were observed from eight cultivars in 2022, and a grain yield decrease from 9% to 49% from eight cultivars occurred in 2023 in the preemergence experiments. Fluridone applied to rice at the 3-leaf stage did not cause a yield penalty to any cultivar in 2022, whereas in 2023, a yield loss occurred from eight cultivars. Yield loss from the DG263L cultivar occurred at the 1 × rate in both experiments, indicating that this cultivar appears to be sensitive to fluridone, regardless of the application timing. Based on these findings, fluridone tolerance is cultivar-dependent. Furthermore, preemergence applications of fluridone to rice should be avoided.https://www.cambridge.org/core/product/identifier/S0890037X25000132/type/journal_articleFluridonericeOryza sativa L.Crop tolerancephytoene-desaturaserice injury
spellingShingle Maria C.C.R. Souza
Jason K. Norsworthy
Pâmela Carvalho-Moore
Amar Godar
Samuel B. Fernandes
Thomas R. Butts
Rice cultivar tolerance to preemergence- and postemergence-applied fluridone
Weed Technology
Fluridone
rice
Oryza sativa L.
Crop tolerance
phytoene-desaturase
rice injury
title Rice cultivar tolerance to preemergence- and postemergence-applied fluridone
title_full Rice cultivar tolerance to preemergence- and postemergence-applied fluridone
title_fullStr Rice cultivar tolerance to preemergence- and postemergence-applied fluridone
title_full_unstemmed Rice cultivar tolerance to preemergence- and postemergence-applied fluridone
title_short Rice cultivar tolerance to preemergence- and postemergence-applied fluridone
title_sort rice cultivar tolerance to preemergence and postemergence applied fluridone
topic Fluridone
rice
Oryza sativa L.
Crop tolerance
phytoene-desaturase
rice injury
url https://www.cambridge.org/core/product/identifier/S0890037X25000132/type/journal_article
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