Growth chamber, greenhouse and field experiments using conventional grain sorghum were conducted to (1) evaluate the differential response of grain sorghum hybrids to POST application of mesotrione at various rates and application timings, and (2) determine the physiology of tolerance of grain sorghum hybrids to mesotrione. Sorghum response ranged from susceptible to tolerant. Mesotrione dose-response studies on four sorghum hybrids revealed that injury symptoms were greatest in Pioneer 85G01 and least in Asgrow Seneca. Mesotrione applied EPOST (early POST) injured sorghum more than when applied at MPOST (mid POST) or LPOST (late POST) timings. Observed injury symptoms were not well correlated with grain yield and were transient, thus injury did not reduce sorghum grain yield. Foliar absorption or translocation of mesotrione in tolerant hybrids did not differ with that of susceptible hybrids but metabolism was more rapid in tolerant than in susceptible hybrids. Initial grain sorghum injury was severe and will likely be a major concern to producers.;Field and growth chambers studies were conducted on herbicide-resistant grain sorghum to (1) determine the effect of quizalofop rates, application timings, and herbicide tank mixes on acetyl-coenzyme A carboxylase (ACCase)-resistant grain sorghum injury and yield, and (2) determine if herbicide metabolism is an additional mechanism that could explain the resistance of ACCase- and acetolactate synthase (ALS)-resistant grain sorghum. Depending on rate, EPOST application caused the greatest injury while the least injury occurred with LPOST application. Crop injury from quizalofop was more prominent at rates higher than the proposed use rate (62 g ha-1) in grain sorghum. Sorghum grain yield was not affected by quizalofop regardless of rates or application timings. Weed control was greater when quizalofop was applied with other herbicides than when applied alone. Herbicide treatments except those that included 2,4-D caused slight to no sorghum injury. Results of the quizalofop metabolism study do not support the involvement of differential metabolism in the observed response of grain sorghum to quizalofop. Rimsulfuron metabolism by ALS-resistant sorghum is more rapid than the susceptible genotypes, thus explaining the observed rapid recovery of grain sorghum plants from rimsulfuron injury in the field.
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機譯：進行了使用常規谷物高粱的生長室，溫室和田間試驗，以（1）評價谷物高粱雜種在不同的施用率和施用時間對甲基磺草酮的POST施用的差異響應，以及（2）確定谷物高粱雜種的耐性生理對甲基磺草酮。高粱的反應范圍從易感到耐受。對四個高粱雜種的甲基磺草酮劑量-反應研究表明，傷害癥狀在先鋒85G01中最大，而在Asgrow Seneca中最小。 Mesotrione施用EPOST（早期POST）對高粱的傷害要比在MPOST（中期POST）或LPOST（后期POST）施用高。觀察到的傷害癥狀與谷物產量沒有很好的相關性，并且是短暫的，因此傷害并未降低高粱的谷物產量。耐性雜種中甲基磺草酮的葉吸收或易位與易感雜種沒有差異，但是耐性中的代謝比易感雜種更快。最初的谷物高粱傷害很嚴重，可能是生產者最關注的問題。對抗除草劑的谷物高粱進行了田間和生長室研究，以（1）確定喹唑磷的施用率，施用時間和除草劑罐混物對乙酰基的影響-輔酶A抗羧化酶（ACCase）的谷物高粱的傷害和產量，并且（2）確定除草劑代謝是否是可以解釋抗ACCase和乙酰乳酸合酶（ALS）的谷物高粱的抗性的另一種機制。根據比率，使用EPOST造成的傷害最大，而使用LPOST造成的傷害最小。 quizalofop對作物的傷害比以高粱的建議使用量（62 g ha-1）高的比率更為突出。高粱谷物產量不受quizalofop影響，無論其施用量或施用時間如何。與其他除草劑一起使用時，與其他除草劑一起使用時，雜草防治效果更好。除包含2,4-D的除草劑處理外，對高粱的傷害輕微至無。 quizalofop代謝研究的結果不支持差異代謝參與谷物高粱對quizalofop的觀察到的反應。抗ALS的高粱對利福磺隆的代謝比易感基因型更快，因此可以解釋該領域從利福磺隆的傷害中觀察到的谷物高粱植物的快速恢復。
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