Investigating herbicide resistant ryegrass

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dc.contributor.advisorViljoen, Charneen_ZA
dc.contributor.advisorPieterse, P. J. en_ZA
dc.contributor.authorBestbeir, Louiseen_ZA
dc.contributor.otherStellenbosch University. Faculty of AgriSciences. Dept. of Agronomy.en_ZA
dc.date.accessioned2024-03-04T10:36:22Z
dc.date.accessioned2024-04-26T20:57:56Z
dc.date.available2024-03-04T10:36:22Z
dc.date.available2024-04-26T20:57:56Z
dc.date.issued2024-03
dc.descriptionThesis (MScAgric)--Stellenbosch University, 2024. en_ZA
dc.description.abstractENGLISH ABSTRACT: Multiple herbicide resistance is an escalating problem in weeds globally. Ryegrass (Lolium spp.) is a major weed in grain cropping systems with documented cases of multiple herbicide resistance across the globe to various amalgamations of glufosinate‑ammonium, glyphosate, acetyl CoA carboxylase, and paraquat. In South Africa, ryegrass plants that survived herbicide applications were tested for multiple herbicide resistance while concurrently investigating spray deposition and adaptations to ryegrass biology based on cropping systems, i.e., Conservation Agriculture ryegrass from Langgewens Research Farm (LS), and resistance. Herbicide applications on young ryegrass plants show a lower spray deposition in terms of Fluorescent Particle Coverage (%) on the adaxis (0.31% ‑ 1.28%) than abaxis (3.93% ‑ 18.13%). Dose-response models varied due to unexpected dose range extremes and showed no paraquat resistance in the LS ryegrass with a lethal dose (LD50) of 0.482X, where X is the recommended dose. Extreme resistance was seen in ryegrass plants from Welgevallen Experimental Farm with differences between the ryegrass plants from the trial field (WS = 11.787X) and the ryegrass plants along the trial field perimeter (WP = 21.727X). Spearman correlations between ryegrass biology and resistance found a strong negative association (r = ‑0.80) between seed weight, mean germination percentage and resistance. Lastly, Welgevallen plants were confirmed to be the first case of glufosinate‑ammonium, glyphosate and paraquat multiple herbicide resistance in a single ryegrass population.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Geen opsomming beskikbaar.af_ZA
dc.description.versionMastersen_ZA
dc.format.extent98 pages : illustrationsen_ZA
dc.identifier.urihttps://scholar.sun.ac.za/handle/10019.1/130530
dc.language.isoen_ZAen_ZA
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subject.lcshHerbicide resistanceen_ZA
dc.subject.lcshGlyphosate -- Physiological effecten_ZA
dc.subject.lcshPlants -- Herbicide toleranceen_ZA
dc.subject.lcshRyegrasses -- South Africaen_ZA
dc.subject.lcshHerbicides -- Application -- South Africaen_ZA
dc.subject.nameUCTDen_ZA
dc.titleInvestigating herbicide resistant ryegrassen_ZA
dc.typeThesisen_ZA
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