Sensitivity of weedy rice populations to Quizalofop

Abstract Background: Rice lines displaying resistance to quizalofop-p-ethyl (quizalofop), an acetyl coenzyme A carboxylase (ACCase)-inhibiting herbicide, were developed to facilitate control of imidazolinone-resistant weedy rice (red rice), as well as other susceptible grasses. Objective: To assess the sensitivity of weedy rice accessions from Brazil to quizalofop. Methods: Two bioassays were conducted on the greenhouse from March to June 2016, in a completely random design with a two-factor factorial combination of treatments and four replications. The factor A was weedy rice accession and factor B was quizalofop rates (0, 25 and 50 g a.i. ha-1). It was assessed a total of 84 genotypes in the two bioassays, composed of 78 weedy rice accessions, 4 rice cultivars, and 2 lines resistant to aryloxyphenoxypropionate (AOPP) herbicides. Quizalofop was applied the 2-leaf stage. Weedy rice control was evaluated at 28 and 22 days after treatment (DAT), respectively for bioassay I and II, using a scale of 0% (no control) to 100% (dead). Results: All weedy rice accessions were susceptible to quizalofop, being controlled 100% with 50 g a.i. ha-1. Rice lines SC 964 and SC 965, resistant to AOPP herbicides, were not injured by quizalofop. Conclusions: quizalofop is an effective tool for weedy rice control in ACCase-resistant rice.

背景：为便于防控抗咪唑啉酮类杂草稻（红稻）及其他敏感禾本科杂草，科研人员培育了对精喹禾灵（quizalofop-p-ethyl）——一种乙酰辅酶A羧化酶（ACCase，acetyl coenzyme A carboxylase）抑制型除草剂——具有抗性的水稻品系。
研究目的：评估来自巴西的杂草稻种质对精喹禾灵的敏感性。
研究方法：2016年3月至6月于温室开展2组生物测定，采用完全随机设计，设置双因素析因处理组合与4次生物学重复。因素A为杂草稻种质，因素B为精喹禾灵施药剂量（0、25、50 g a.i. ha⁻¹，其中a.i.为有效成分，ha⁻¹为每公顷）。两组生物测定共纳入84份基因型材料，包含78份杂草稻种质、4个水稻栽培品种及2个芳氧苯氧丙酸酯类（AOPP，aryloxyphenoxypropionate）除草剂抗性水稻品系。精喹禾灵于供试材料2叶期施药。分别于施药后28天（生物测定I）和22天（生物测定II），采用0%（无防控效果）至100%（植株完全死亡）的分级标准评估杂草稻防控效果。
研究结果：所有供试杂草稻种质均对精喹禾灵敏感，施用量达50 g a.i. ha⁻¹时防控率达100%。对AOPP类除草剂具有抗性的水稻品系SC 964与SC 965未受精喹禾灵药害。
研究结论：精喹禾灵可作为防控抗ACCase抗性水稻田中杂草稻的有效工具。