Resistance to Glyphosate in Populations of Digitaria insularis

ABSTRACT: The intensive use of glyphosate can select resistant populations. This study aimed at evaluating the occurrence of glyphosate resistance in populations of D. insularis in agricultural areas. Three experiments were conducted in randomized block experimental design with four replications. The Resistance Degree (RD) was determined by a dose-response curve in the evaluated populations: Experiment 2012, São Camilo (R01 and R02) and Palotina (R03, R04 and S05-susceptible); Experiment 2013 Palotina (R06 and R12), Katueté/Paraguay (R07), Toledo (R08 and R10), Cascavel (R09), São Miguel do Iguaçu (R11), Dom Eliseu/Pará (S13-susceptible); Experiment 2015 Nova Aurora (R14), Iracema do Oeste (R15 and R16), Jesuitas (R17 and R18), Tupãssi (R19), Jotaesse (R20), Espigão Azul (R21) and Palmitopolis (S22- susceptible). In 2012, it was possible to confirm a moderate resistance (RD = 1.1 to 5.0) only in R03; and populations R01, R02 and R04 were highly resistant (RD>5.0). In 2013, populations R09, R10, R11 and R12 showed resistance, while R06, R07 and R08 were highly resistant. In 2015, the R14, R16, R18, R19 and R20 populations showed moderateresistance, and R15 and R18 were highly resistant. Only R21 was susceptible. It was found that 83% of producers use the no-tillage system, 100% use the succession soybean/corn with 90% transgenic varieties, 45% of producers cannot explain the procedure regulation/sprayer calibration. Around 62% use practices to prevent the selection of resistant biotypes. Resistance was confirmed in 89.5% of the populations. The adopted agronomic practices may explain these results.

摘要：草甘膦的大量使用会筛选出抗性种群。本研究旨在调查农业区域内D. insularis种群对草甘膦的抗性发生情况。本研究采用随机区组试验设计，设置4次重复，共开展3组试验。通过剂量-反应曲线确定供试种群的抗性程度（Resistance Degree, RD）：2012年试验涉及圣卡米卢（São Camilo，R01、R02）与帕洛蒂纳（Palotina，R03、R04及敏感种群S05）；2013年试验涉及帕洛蒂纳（R06、R12）、巴拉圭卡图埃特（Katueté/Paraguay，R07）、托莱多（Toledo，R08、R10）、卡斯卡韦尔（Cascavel，R09）、伊瓜苏河畔圣米格尔（São Miguel do Iguaçu，R11）以及帕拉州多姆埃利塞乌（Dom Eliseu/Pará，敏感种群S13）；2015年试验涉及新奥罗拉（Nova Aurora，R14）、西伊拉塞马（Iracema do Oeste，R15、R16）、赫苏伊塔斯（Jesuitas，R17、R18）、图帕西（Tupãssi，R19）、约泰塞（Jotaesse，R20）、埃斯皮冈阿祖尔（Espigão Azul，R21）与帕尔米托波利斯（Palmitopolis，敏感种群S22）。2012年，仅R03种群表现出中等抗性（RD=1.1~5.0），R01、R02及R04种群则为高抗性（RD>5.0）；2013年，R09、R10、R11与R12种群表现出抗性，R06、R07、R08种群为高抗性；2015年，R14、R16、R18、R19及R20种群表现为中等抗性，R15与R18种群为高抗性，仅R21种群表现为敏感。调查显示，83%的生产者采用免耕种植制度，100%采用大豆-玉米轮作体系，其中90%使用转基因品种；45%的生产者无法阐明施药规程或喷雾器校准方法。约62%的生产者采取了防控抗性生物型筛选的相关措施。本研究检测的种群中，89.5%被证实存在草甘膦抗性，当前采用的农艺措施或可解释上述研究结果。