谷子苗后广泛使用的茎叶处理除草剂主要是二甲四氯和2,4-滴异辛酯等,这些药剂只能防除田间的阔叶杂草[4-5]。抗除草剂烯禾啶的谷子品种应用广泛,但对其他类型除草剂的耐药性较低[6]。氰氟草酯（cyhalofop-butyl）是美国陶氏益农公司1987年开发的乙酰辅酶A羧化酶抑制剂,属于芳氧苯氧丙酸酯类除草剂,能够有效防除稗草和千金子等水稻田的禾本科杂草[7],同时对马唐（Digitria sanguinalis L.）、看麦娘和牛筋草（Eleusine indica L.）等属于C4植物的禾本科杂草也有很高的防效[8]。氰氟草酯还可以与其他除草剂复配,如五氟磺草胺和二氯喹啉酸等[9-10],以进一步扩大杀草谱和提高防效。
1 材料与方法
1.1 试验材料
谷子品种冀谷39和豫谷18由河北省农林科学院谷子研究所提供,冀谷39是采用杂交方法选育出的抗咪唑啉酮类兼抗烟嘧磺隆除草剂的品种,豫谷18为常规品种。室内生物测定试验使用的牛筋草和谷莠子（Setaria faberii Herrm.）种子是2019年采于河北省石家庄市堤上村。10%氰氟草酯乳油由山东绿霸化工股份有限公司生产。
1.2 测定项目与方法
1.2.1 杂草对氰氟草酯敏感性
室内生物测定试验于2020年在河北省农林科学院粮油作物研究所生物培养室进行,温度25℃,光照和黑暗各12h。在底部有孔的塑料花盆（8cm×8cm×10cm）中加入3/4的专用育苗土,花盆置于托盘中,托盘里加入适量水,通过底部虹吸的方式待水渗至土表后,置于植物培养室中,分别播入牛筋草和谷莠子种子后覆土1cm。植株2叶时进行间苗,每盆定苗10株,待植株3~4叶时使用3WP-2000型行走式喷雾塔用药,喷液量450L/hm2。试验用药按照表1进行,设6个处理,4次重复。药后18d测定植株地上部鲜重,鲜重抑制率（%）=（空白对照鲜重-处理鲜重）/空白对照鲜重×100。
表1 室内生物测定供试植物与除草剂剂量
Table 1
| 处理 Treatment | 豫谷18 Yugu 18 | 冀谷39 Jigu 39 | 谷莠子 S. faberii | 牛筋草 E. indica |
|---|---|---|---|---|
| 氰氟草酯 Cyhalofop-butyl | 15.625 | 200 | 15.625 | 15.625 |
| 31.250 | 250 | 31.250 | 31.250 | |
| 62.500 | 300 | 62.500 | 62.500 | |
| 125.000 | 350 | 125.000 | 125.000 | |
| 250.000 | 400 | 250.000 | 250.000 | |
| 空白对照Control | – | – | – |
由于氰氟草酯目前在谷田尚无推荐剂量,故以其在水稻田的推荐剂量90~120g a.i./hm2作为评价其对靶标植物敏感性的基本标准,当氰氟草酯对杂草的GR90（鲜重抑制率90%所需要的剂量）小于90g a.i./hm2时,该杂草对氰氟草酯高度敏感;GR90介于90~120g a.i./hm2时,该杂草对氰氟草酯中度敏感;GR90介于120~240g a.i./hm2时,该杂草对氰氟草酯一般敏感;GR90大于240g a.i./hm2时,该杂草对氰氟草酯不敏感。
使用DPS统计分析工具计算GR90,以靶标植物的生长抑制率几率值（y）和剂量对数值（x）为变量建立回归方程y=b+ax,通过方程计算出靶标植物喷施氰氟草酯后的GR90。
1.2.2 谷子对氰氟草酯的耐药性
谷子播种、培养、用药处理及调查的方法与1.2.1一致。
当氰氟草酯对谷子的GR10（鲜重抑制率10%所需要的剂量）大于240g a.i./hm2时,氰氟草酯对谷子安全;GR10介于120~240g a.i./hm2时,氰氟草酯对谷子较安全;GR10低于120g a.i./hm2时,对谷子不安全。
按照1.2.1的方法计算不同谷子品种喷施氰氟草酯后的GR10和GR50（鲜重抑制率50%所需要的剂量）。氰氟草酯对谷子和杂草的选择性指数（selection index,SI）和抗药性指数（resistance index,RI）分别按下式计算：SI=谷子GR10/杂草GR90,RI=抗性谷子GR50/敏感谷子GR50。
氰氟草酯对谷子和杂草之间的选择性使用SI进行评价,SI≥2.0时,氰氟草酯对谷子和该杂草的选择性高,1.0≤SI<2.0时,氰氟草酯的选择性一般,SI<1.0时,氰氟草酯的选择性差。
1.3 田间试验
田间试验设于河北省石家庄市马庄村,条播,行距40cm,密度45万株/hm2,小区面积20m2,田间管理措施一致。田间禾本科杂草为牛筋草、谷莠子和马唐,谷子品种为冀谷39,2020年6月21日播种。田间试验设计为完全随机区组排列,共设置5个处理,分别为氰氟草酯40、55、70、110g a.i./hm2和空白对照,重复4次。于杂草3~4叶期喷施除草剂,喷液量为525L/hm2。田间小区施药器械为HD400背负式喷雾器,扇形喷头,由新加坡利农私人有限公司生产。药后18d,每小区取1m2调查杂草的种类、株数和鲜重,同时取20株谷子测量株高和地上部鲜重。杂草株数防效（%）=（空白对照区杂草株数-处理区杂草株数）/空白对照区杂草株数×100,杂草鲜重防效（%）=（空白对照区杂草鲜重-处理区鲜重）/空白对照区杂草鲜重×100。
1.4 数据处理
使用Excel对数据进行整理计算,使用SPSS进行单因素随机区组方差分析,用Duncan氏新复极差法进行显著性多重比较。
2 结果与分析
2.1 室内杂草对氰氟草酯的敏感性
随着氰氟草酯剂量增加,对牛筋草的抑制作用迅速提高。15.625g a.i./hm2剂量对牛筋草的生长有轻微抑制作用,31.250g a.i./hm2剂量下牛筋草的生长受到严重抑制,62.500g a.i./hm2剂量时牛筋草全部枯死。15.625g a.i./hm2剂量对谷莠子的生长有抑制效果,31.250g a.i./hm2剂量下谷莠子的生长受到严重抑制,125.000g a.i./hm2剂量下谷莠子大部分枯死。
从图1可以看出,氰氟草酯对牛筋草和谷莠子的鲜重防效符合剂量―效应曲线,在15.625~125.000g a.i./hm2剂量下,鲜重防效随着剂量增加而迅速增加,剂量125.000g a.i./hm2时鲜重防效均达到90%以上。
图1
图1
氰氟草酯对杂草的鲜重防效
Fig.1
Fresh weight control effects of cyhalofop-butyl on weeds
由表2可知,氰氟草酯对牛筋草的GR50和GR90分别为10.19和45.02g a.i./hm2,对谷莠子的GR50和GR90分别为20.22和124.13g a.i./hm2。依据杂草对除草剂敏感性的评价标准,牛筋草对氰氟草酯高度敏感,谷莠子对氰氟草酯一般敏感。
表2 杂草对氰氟草酯的敏感性
Table 2
| 杂草 Weed | 回归方程 Regression equation | 相关 系数 r | 95%置信限 95% confidence limit (g a.i./hm2) | |
|---|---|---|---|---|
| GR50 | GR90 | |||
| 牛筋草 E. indica | y =3.00+1.99x | 0.94 | 10.19 （4.29~24.23） | 45.02 （29.16~69.51） |
| 谷莠子 S. faberii | y =2.88+1.63x | 0.98 | 20.22 （14.27~28.66） | 124.13 （93.88~164.11） |
回归方程中x为药剂剂量的常用对数,y为鲜重抑制率的几率值,下同
In the regression equation, x and y were the common logarithm of the cyhalofop-butyl dosage and the probability value of the biomass inhibition ratio, respectively, the same below
2.2 室内谷子对氰氟草酯的耐药性
由表3可知,氰氟草酯对豫谷18和冀谷39的GR10分别为13.70和284.05g a.i./hm2,依据安全性评价标准,豫谷18和冀谷39分别对氰氟草酯为高度敏感和不敏感。抗除草剂谷子品种冀谷39的RI是普通谷子品种豫谷18的9.65倍。
表3 谷子对氰氟草酯敏感性测定结果
Table 3
| 谷子 Millet | 回归方程 Regression equation | 相关系数 r | 95% 置信限95% confidence limit (g a.i./hm2) | RI | |
|---|---|---|---|---|---|
| GR10 | GR50 | ||||
| 豫谷Yugu 18 | y=1.33+2.10x | 0.94 | 13.70（6.25~30.04） | 55.86（35.57~87.73） | 1.00 |
| 冀谷Jigu 39 | y=4.61x-7.59 | 0.91 | 284.05（251.05~321.40） | 538.94（386.65~751.20） | 9.65 |
由表4可知,氰氟草酯在豫谷18与牛筋草和谷莠子之间的SI分别为0.30和0.11,均小于1.0,表明氰氟草酯在豫谷18与牛筋草和谷莠子之间无法安全作出选择。氰氟草酯在冀谷39与牛筋草和谷莠子之间的SI分别为6.31和2.29,均大于2.0,表明氰氟草酯在冀谷39与牛筋草和谷莠子之间的选择性高,可在冀谷39上安全地使用。
表4 氰氟草酯对不同谷子品种和杂草的选择性指数
Table 4
| 材料 Material | 剂量 Dosage | 谷子 Millet | 牛筋草 E. indica | 谷莠子 S. faberii |
|---|---|---|---|---|
| 豫谷Yugu 18 | GR10 | 13.70 | ||
| 杂草Weed | GR90 | 45.02 | 124.13 | |
| 选择性指数SI | 0.30 | 0.11 | ||
| 冀谷Jigu 39 | GR10 | 284.05 | ||
| 杂草Weed | GR90 | 45.02 | 124.13 | |
| 选择性指数SI | 6.31 | 2.29 |
2.3 田间氰氟草酯的杂草防治效果
结果（表5）表明,随氰氟草酯用药剂量的增加,田间禾本科杂草的株数防效和鲜重防效也随之提高。相同用药量下,氰氟草酯对牛筋草和谷莠子的鲜重防效高于株数防效,但氰氟草酯对不同种类杂草的防除效果有明显的不同。氰氟草酯的用药量在55g a.i./hm2时对牛筋草的株数防效为87.4%,鲜重防效达95.2%;氰氟草酯对马唐的用药量在110g a.i./hm2时株数防效和鲜重防效分别为97.0%和97.1%;氰氟草酯用药量低于70g a.i./hm2时对谷莠子的防效不佳,110g a.i./hm2时的株数防效和鲜重防效分别为67.2%和80.5%。氰氟草酯的防效从高到低依次为牛筋草、马唐和谷莠子,与室内生物测定结果一致。
表5 氰氟草酯药后18d杂草防效
Table 5
| 氰氟草酯 Cyhalofop-butyl (g a.i./hm2) | 株数防效Control effect of plant number (%) | 鲜重防效Fresh weight control effect (%) | |||||||
|---|---|---|---|---|---|---|---|---|---|
| 马唐 D. sanguinalis | 牛筋草 E. indica | 谷莠子 S. faberii | 杂草合计 Overall of weed | 马唐 D. sanguinalis | 牛筋草 E. indica | 谷莠子 S. faberii | 杂草合计 Overall of weed | ||
| 40 | 54.5c | 37.0b | 0.0c | 9.3c | 30.7d | 83.1b | 45.3b | 53.5b | |
| 55 | 69.7bc | 87.4a | 11.5bc | 45.2b | 54.3c | 95.2ab | 43.3b | 55.7b | |
| 70 | 78.8b | 92.9a | 19.1b | 52.2b | 77.5b | 97.5a | 47.5b | 60.2b | |
| 110 | 97.0a | 100.0a | 67.2a | 82.2a | 97.1a | 100.0a | 80.5a | 85.6a | |
同列不同字母为处理之间差异显著（P < 0.05）
The different letter in the same column indicate significant different at 0.05 level
2.4 田间氰氟草酯对谷子的安全性
图2
图2
氰氟草酯药后18d对冀谷39株高和鲜重的影响
不同字母表示处理间差异显著（P < 0.05）
Fig.2
Effects on Jigu 39 plant height and fresh weight after cyhalofop-butyl application 18 days
Different letter indicate significant different between treatments at 0.05 level
3 讨论
分子生物学和基因工程技术的进步使得选育并利用抗除草剂作物来有效防控田间恶性杂草成为现实[14-15],全球抗除草剂作物的种植面积迅速扩大[16-17]。目前谷田仍然缺乏安全的茎叶处理除草剂,因此开发抗除草剂谷子品种是解决这一难题的方向[18]。冀谷39是河北省农林科学院通过杂交方法选育出的抗咪唑啉酮类除草剂兼抗烟嘧磺隆的谷子品种,在生产上大面积推广应用,该品种对咪唑啉酮和烟嘧磺隆类除草剂的抗性已经很明确,但对芳氧苯氧丙酸酯类除草剂的耐药性鲜有报道,尤其是对禾本科杂草有良好防效的氰氟草酯的敏感性尚不明确。不同基因型作物对同一种抑制剂的敏感性是有差别的[19],同一基因型对同一靶标位点的抑制剂的抗药性也有差异[20]。本试验结果表明,氰氟草酯110g a.i./hm2对冀谷39的生长没有影响,而在氰氟草酯增加剂量后杂草和豫谷18植株的枯死比例迅速提高,说明冀谷39可以较安全地使用氰氟草酯来防除禾本科杂草。
氰氟草酯对杂草的研究多为水稻田的稗草、千金子等[13,21],对旱粮作物田的杂草研究较少。郭文磊等[22]在水稻田使用氰氟草酯90~120g a.i./hm2对牛筋草的防除效果为90.4%~94.5%,高于对马唐（89.0%~92.4%）的防效,与本研究的田间结果基本一致。氰氟草酯对马唐的敏感性随叶龄增加而降低,1~1.5叶期马唐对氰氟草酯的敏感性最高,3~4叶期马唐GR50的95%置信区间为20.84~29.97g a.i./hm2[23],与本研究结果部分相符,可能是不同生物型马唐的敏感性差异造成的。氰氟草酯对谷莠子的敏感性未见报道,对其近缘的狗尾草的敏感性仅有少量报道[7]。本研究结果表明,谷莠子对氰氟草酯一般敏感。
4 结论
常规谷子品种豫谷18对氰氟草酯敏感,不能使用氰氟草酯,而抗除草剂谷子品种冀谷39对氰氟草酯有较强的耐药性,可以较安全地使用其防除禾本科杂草,在杂草3~4叶期,茎叶喷施氰氟草酯能有效防控马唐、牛筋草和谷莠子等谷田禾本科杂草。其中牛筋草对氰氟草酯的敏感性最高,其次是马唐,谷莠子对氰氟草酯一般敏感。
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PMID:31378350
[本文引用: 1]
Chinese sprangletop (Leptochloa chinensis (L.) Nees) is one of the most troublesome grass weeds in rice in China. Seven suspected cyhalofop-butyl-resistant L. chinensis populations were collected from different rice fields with a history of cyhalofop-butyl use. The level of resistance and resistance mechanisms in seven populations were studied. Dose-response tests indicated that five populations (JS3, JS4, JS6, JS7 and JS8) had evolved high-level resistance (26.9 to 123.0-fold) to cyhalofop-butyl compared with the susceptible (S) population, and other two populations (JS2 and JS5) were still sensitive to the herbicide. Two acetyl-coenzyme A carboxylase (ACCase) genes were cloned from each population, and three different ACCase mutations (Ile-1781-Leu, Trp-1999-Cys, and Trp-2027-Cys) in ACCase2 gene were determined in different resistant (R) populations. In addition, no resistance-conferring mutations was detected in the R population (JS7), and ACCase gene expression was similar between the S and R populations. Thus, non-target-site resistance mechanisms may be involved in the JS7 population. Moreover, the patterns of cross-resistance of JS6 (Ile-1781-Leu), JS4 (Trp-1999-Cys), JS8 (Trp-2027-Cys), and JS7 (unknown resistance mechanisms) populations to other ACCase-inhibiting herbicides were determined. The JS6 and JS8 populations showed resistance to fenoxaprop-P-ethyl, metamifop, clethodim and pinoxaden, the JS4 population was resistant to fenoxaprop-P-ethyl, metamifop and pinoxaden, and the JS7 population had resistance only to fenoxaprop-P-ethyl and metamifop. These results indicated the diversity of the target-site mutations in ACCase gene of L. chinensis, and provide a better understanding of cross-resistance in L. chinensis, which would be helpful for the management of cyhalofop-butyl-resistant L. chinensis.Copyright © 2019 Elsevier Inc. All rights reserved.
不同叶龄千金子、稗和马唐对氰氟草酯和五氟磺草胺的敏感性
