Resistance of Barnyard Grass(Echinochloa crusglli) to Quinclorac in Double-harvest Rice Area in Hunan Province of China

[ Objective] The paper was to study the resistance of barnyard grass to quinclorac in double-harvest rice area in Hunan Province of China. [ Method ] Using whole-plant determination method, the resistance of 36 biotypes of barnyard grass to quinclorac in double-harvest rice area in Hunan Province was studied. [ Result ] The biotype collected from Lijiaping Town of Shaoyang County was the most susceptible barnyard grass to quinclerac, and the EC50 value was 70. 253 1 g a. i./hm2 , so it was recognized as the sensitive biotype. The biotypes collected from Caowei Town of Yuanjiang County （ HN3 and HN4 from direct seeding rice fields） and Zhongyukou Town of Nanxian County presented very high resistance to quinclorac ; the ECho values were 1 999. 122 5, 1 664.544 6 and 1 022.739 5 g a. i./hm2, and their resistance indexes reached 28.46, 23.69 and 14.56, respectively, indicating that these throe biotypes hod high level of resistance to quinclo- rac. EC50 values of about 22 biotypes were ranged from 144. 837 3 to 408.289 4 g a. i./hm2, and resistance indexes were ranged from 2.06 to 5.81, indicating that these biotypes hod produced resistance to quinclorac. EC50 values of other 10 biotypes were ranged from 98.032 6 to 138. 660 9 g a. i./hm2, and the resistance in- dexes were ranged from 1.40 to 1.97, indicating that the sensitivity of barnyard grass in these places was decreasing. [ Conclusion] The paper provided guidance for scientific and rational use of quinclorac in paddy fields.

Control Effects of Mixture of Metamifop and Cyhalofop-butyl on Annual Weeds Barnyard Grass in Direct-seeding Paddy Field

In order to explore the control effects of 10% metamifop EC and 20%cyhalofop-butyl OD on barnyard grass(Echinochloa crusgalli(L.) Beauv.) as well as their safety to rice in rice direct-seeding paddy field, field efficacy experiments were carried out in Taoyuan County and Hanshou County of Hunan Province. The results showed that the control effect of different pesticide treatments on barnyard grass was good, and the control effect reached more than 93%. Of which, 10% metamifop EC 2 250 mL/hm^(2)+20% cyhalofop-butyl OD 1 500 mL/hm^(2)had the best control effect,exceeding 99% and each treatment had no significantly ponisonous to rice. However,considering cost-saving and effect-increasing, it was recommended to use 10%metamifop EC 1 050 mL/hm^(2)mixed with 20% cyhalofop-butyl OD 1 050 mL/hm^(2)for the control of barnyard grass, which not only had the effect of controlling barnyard grass, but also was safety to rice.

Allelopathic Potential of Rice （Oryza sativa L.） Cultivars on Barnyard Grass （Echinochloa crus-galh~

Laboratory and greenhouse studies were conducted to assess the allelopathic potential of 12 rice cultivars on barnyard grass. Polyethylene glycol （PEG） was used to determine the influence of osmotic potential on the bioassay materials. Effect of different concentrations of stem, root, and leaf extracts of rice cultivars on seed germination, radicle and primary shoot length of barnyard grass seedlings, and rate of respiration of root pieces were investigated in the laboratory experiments. Shoot height and dry weight of weed stands were studied in the greenhouse, Also total peroxidase activity, chlorophyll pigment and mitotic index were determined. Results indicated that, among rice cultivars, Mehr, Tarom-mahali, G3, Nemat, and Shahpasand caused the most inhibition effects on investigated factors. Amol-3 showed the least negative effects on growth of seedlings and stands of barnyard grass. In laboratory, the Mehr cultivar demonstrated the maximum inhibitory effects by reducing barnyard grass seed germination percentage （88%）, radicle length （100%）, primary shoot length （83%）, and root respiration （85%） Cell division, expressed as mitotic index, was significantly reduced in the presence of rice aqueous extracts. Mehr cultivar had higher inhibitory effect on mitosis compared to Amol-3. In greenhouse, the same cultivar showed the maximum inhibitory effect by reducing barnyard grass height （45%） and dry weight （64%）. With increase in extract concentration, the inhibitory effect increased. Leaf extract from rice plants was more effective compared with the root and stem extracts. Comparison of rice cultivars and PEG indicated that any reduction in germination and growth of barnyard grass using rice extract concentrations of 5% and 10% must have been the result of allelochemicals in the extracts. Lower extract concentrations showed a more pronounced inhibitory effect in the laboratory as compared to the greenhouse studies. These results suggest that rice leaf extracts may be a source of natural herbicide.

Field experimental study on pullout forces of rice seedlings and barnyard grasses for mechanical weed control in paddy field

Pullout forces of rice seedling and barnyard grass were tested by universal testing machine controlled by WDW-5 type microcomputer to obtain the pullout forces of rice seedling and barnyard grass.The measured pullout force was used to improve the weeding rate and reduce the rice seedling damage rate caused by mechanical weeding device.According to the measured continuous curve of pullout forces of rice seeding and barnyard grasses in weeding period,the best range of force required to pull out barnyard grasses from soil with no injury and damage to rice seedlings was discussed.Reasons for the difference in the pulling force were analyzed.Results show that,with the increment of the number of single cell rice seedlings the pullout force increases.The pullout forces of single cell rice seedlings and barnyard grasses at first increased slowly reaching the maximum value followed by rapid drop and finally it remained steady.The minimum pullout forces recorded during rice seedlings at the first and the second weeding periods were 2.57 N and 9.70 N,respectively,while the minimum forces during the first and second weeding periods were recorded as 1.24 N and 7.51 N,respectively,for barnyard grasses.The results show that the pullout forces of weeding to rice seedlings and barnyard grasses should be within 1.24 N to 2.57 N and 7.51 N to 9.70 N respectively in the first and second weeding periods.

Resistance Level and Metabolism of Barnyard-Grass (Echinochloa crusgalli(L.) Beauv.) Populations to Quizalofop-p-ethyl in Heilongjiang Province,China

Eleven barnyardgrass populations were assayed. The highest resistant population was Geqiushan R with RI 125.45 resulted from the seed assay and 87.29 resulted from the whole plant bioassay followed by 853 R with RI 2.79 resulted from the seed assay and 6.04 resulted from the whole plant bioassay. The resistance level of other nine populations was low with RI 1.13-2.61 resulted from the seed assay and 1.48-3.63 resulted from the whole plant bioassay. The activity of an important metabolic enzyme glutathione S-transferases （GSTs） and three protective enzymes （SOD, POD, and CAT） were determined in vivo for Geqiushan R, 853 R, and Wudalianchi R. Compared with the S controls, the activities of POD in Geqiushan R, GSTs in 853 R, and Wudalianchi R were increased.

不同大豆品种浸提液对稗草和苜蓿的除草活性

为探索大豆在种植过程中潜在的化感作用,研究了6个不同大豆品种浸提液对稗草和苜蓿的除草活性。采用培养皿滤纸法、土壤封闭法和茎叶喷雾法测定了其对稗草和苜蓿的化感作用,并挑选出除草活性最高的大豆品种浸提液进行除草活性物质分析。结果表明:种子萌发试验中,在0.01 g/mL浓度下,2701品种大豆乙醇浸提液对稗草和苜蓿的根长抑制率分别是65.3%和62.0%、对二者的芽长抑制率分别是80.2%和17.5%,湘24品种大豆乙醇浸提液对稗草和苜蓿的根长抑制率为79.8%和70.9%、对二者的芽长抑制率分别是46.0%和35.6%;土壤封闭试验中,在0.01 g/mL浓度下,湘24品种大豆乙醇浸提液对稗草和苜蓿的抑制率为48.4%和35.2%;茎叶喷雾试验中,在0.01 g/mL浓度下,湘24品种大豆乙醇浸提液对稗草和苜蓿的抑制率为67.0%和93.6%,2701品种大豆乙醇浸提液的抑制率为76.4%和93%;除草活性物质追踪结果表明黄酮类次生代谢物质在浸提液中含量相对较高。由此可见,湘24、2701品种大豆乙醇粗提液具有一定的除草活性。

稗草EcHPPD基因的克隆及生物信息学分析

旨在克隆稗草对羟基苯基丙酮酸双氧化酶(HPPD)基因为探究其基因功能提供基础,从而更好地开发除稗剂。以稗草叶片为材料,用同源克隆和cDNA末端快速克隆(RACE)技术克隆EcHPPD基因序列,用生物信息学软件分析其特征。EcHPPD基因的编码序列全长1317 bp,其编码蛋白质由439个氨基酸组成,相对分子质量为46.659 kD,等电点为5.30。稗草与同处禾本科的Dichanthelium oligosanthes(OEL23409.1:8-249)的HPPD蛋白进化程度最为相近。EcHPPD三级建模蛋白结构由两条链构成,有2个Fe^(2+)结合位点,并能与吡唑特活性中心骨架通过氢键相互作用。EcHPPD可能与HGO、HPT1、TAT3、AT5G36160、TAT7等11个蛋白产生互作。本研究报道了EcHPPD基因序列并对其进行了生物信息学分析,为创制新的HPPD抑制剂提供理论依据。

应用二次通用旋转组合设计禾长蠕胞菌制剂配方

禾长蠕孢菌(Helminthosporium gramineum Rabenh.f.sp.echinochloae)是一种稻田微生物除草潜力菌。为提高其在田间应用的效果,本文以稗草为靶标杂草,前期筛选到的助剂(增效剂、溶剂油、稳定剂、乳化剂)为编码因子,采用二次通用旋转组合设计配方,根据各配方对稗草的致死率建立回归方程,并通过方差分析,对方程进行优化,最终优化得到禾长蠕孢菌孢子制剂的配方为:1.0 g孢子粉中添加0.25 mL大豆油、0.49 g羧甲基纤维素钠、0.1 mL SP-20,增效剂10%吡嘧磺隆WP 6.56 mg和2.5%五氟磺草胺OD 26μL。研究结果有助于HGE菌后续商品化应用。

旱稻(Oryza sativa)×长芒稗(Echinochloa caudata)远缘杂交后代结实率及杂种优势分析

以旱稻基因型旱 65(OryzasativaL .)为母本 ,稗草长芒稗 (Echinochloacaudata)为父本进行远缘杂交 ,获得实粒种子。连续 5年试验结果表明 :( 1 )F0 高度不孕 ,并伴有杂交种发育夭折现象。去雄 82 4朵小花 ,结实率为 1 2 1‰。 ( 2 )F1杂种优势明显 ,育性正常 ,结实率 92 2 6% ,单株产量超母本 80 3 9%。 ( 3 )F2 农艺性状分离严重 ,但育性无分离。群体 40 5株无不育株出现。选育出的优良变异单株“远F2 1” ,超亲优势为 55 64%。 ( 4)对“远F2 1”衍生F3株系 1 60株考种株穗数、株高、穗长、主茎穗一级枝梗数、穗总粒数、穗实粒数诸性状 ,平均超亲优势分别为 2 3 2 %、1 5 1 8%、47 2 6%、3 3 84%、2 4 2 6%及 2 1 62 % ,差异显著。 ( 5)F5光合速率测定 ,超母本2 9 72 %。远缘杂交对不同属间引入目的基因 ,非常有效。

稗草休眠特性及其解除

研究了稗草在不同环境条件下的休眠特性及其解除方法。结果表明,稗草种子在成熟后都将进入休眠,不同环境条件下其休眠期不一样。2004年7月采集的稗草种子在地下贮存条件下5个月就能打破休眠,且持续6个月一直处于休眠解除状态。室内常温条件下需12个月才能打破休眠,而冰箱中贮存12个月不能解除稗草种子的休眠。1 000.0 mg/L赤霉酸浸泡240 h和硫酸浸泡10-20 min均能解除稗草种子的休眠,但其他处理不能有效解除稗草种子的休眠。

五爪金龙中香豆素类物质含量及其对福寿螺、水稻和稗草的影响

在不同季节采集并测定了入侵植物五爪金龙不同器官中伞形花内酯(Umbelliferone(UMB))和东莨菪亭内酯(Scopoletin(SCO))的含量、同时室内分析了这两种物质的杀螺效果及其对水稻和稗草生长的影响、并研究了这两种物质在土壤中的降解情况。结果表明:五爪金龙植株中SCO含量高于UMB含量,两物质均是夏季含量最高,春季次之,秋冬季低,SCO夏季在茎中含量最大,秋冬季幼茎和幼叶中含量较高;UMB对福寿螺的毒杀力强于SCO,UMB浓度为C2(200μg/mL)时处理24 h对福寿螺的致死率达100%,而SCO浓度为C2时处理24 h对福寿螺的致死率仅为8%;SCO对水稻和稗草苗生长的影响较UMB强,在C0(50μg/mL),C1(100μg/mL)、C2浓度下均促进水稻及稗草苗的生长,而C3(400μg/mL)浓度下则抑制水稻和稗草苗的生长。UMB和SCO混合溶液比单一物质在相同浓度的杀螺效果及对水稻和稗草的生长影响要强;UMB和SCO在土壤中10 d内完全降解。入侵植物五爪金龙中的次生物质UMB和SCO在稻田中的生态效应值得进一步研究。

几种豆科牧草地上部水浸提液对稗草种子和幼苗的化感效应

用砂培法研究毛苕子(Viciavillosa)、紫花苜蓿(Medicagosativa.)、白三叶(Trifoliumrepens)、红三叶(Trifoliumpratense)和黄花草木樨(Melilotusofficinalis)花期地上部水浸提液对稗草(Echinochloacrusgalli)的化感效应。结果表明,供试草种水浸提液对稗草种子萌发和幼苗生长的化感作用具有明显的种间差异;其中对毛苕子和黄花草木樨种子发芽的抑制作用强于其它3种,抑制率达60%以上;紫花苜蓿对稗草幼苗生长的抑制作用强,特别是对根的抑制作用显著强于其它4个草种;白三叶和红三叶仅在水浸提液浓度0.1g/mL时,对稗草鲜根重表现出显著的抑制效应(P<0.05);此外,供试草种浸提液对稗草的化感作用,随着浓度的升高,抑制作用随之增强。

旱稻(Oryza sativa)/稗草(Echinochloa caudata)//高梁(Sorghum bicolor)三属杂种表现及分析

以旱稻基因型远F2 1 [旱 65 (Oryzasativa) 长芒稗 (Echinochloacaudata) ]为母本 ,高粱(Sorghumbicolor)基因型沈农 1 33为父本 ,进行属间远缘杂交 ,获得三属间杂交实粒种子。对杂交种F0 、F1、F2 代连续观察结果表明 :( 1 )杂交F0 代高度不孕 ,并伴有杂交种发育夭折现象发生 ,结实率仅为 2 63‰ ;( 2 )F1杂种优势明显 ,株高、穗长、1级枝梗数、小花数、结实粒数、结实率、千粒重诸性状超母本优势为 0 61 %～ 2 0 5 6% ;主茎叶片数多于母本 1片 ,总叶面积超亲优势为 1 1 95 % ;F1出现母本没有的红芒、红护颖和紫柱头 3个可遗传性状 ;( 3)F2 除在生育期、株高及穗长等性状发生分离外 ,其典型特征是穗型、芒性、芒色、柱头颜色。

浙江省稻田稗草对二氯喹啉酸的抗药性

应用琼脂法测定了浙江省稻区21个稗草生物型对二氯喹啉酸的抗性水平。结果表明,绍兴市郊(2003年)的稗草生物型对二氯喹啉酸最敏感,其EC50为0.3268mg/L。以其为敏感生物型,绍兴陶堰(2003年)和温州塘下(2003年)的稗草生物型对二氯喹啉酸的EC50分别为234.8、227.4mg/L,抗性比分别达到718.48和695.84,表明这两种稗草生物型的抗药性处于极高抗水平。浙江杭州(2003年)的稗草生物型对二氯喹啉酸的EC50为13.47mg/L,抗性比为41.22,表明该稗草生物型处于高水平抗性阶段。绍兴皋埠(2003年)的稗草生物型对二氯喹啉酸的抗药性还处于低水平抗性阶段,其EC50和抗性比分别为2.096mg/L和6.41。而其余16个稗草生物型对二氯喹啉酸的EC50为0.4953～1.315mg/L,抗性比为1.52～4.02,表明这些地方稗草生物型对二氯喹啉酸敏感。

4种酚酸类化感物质与丁草胺混用对稗草生长抑制的互作效应

室内生物测定阿魏酸、对羟基苯甲酸、香豆酸和水杨酸4种酚酸类化感物质与丁草胺混用对稗草生长的抑制效果。采用Gowing法分析互作效应,探讨利用水稻化感作用实施减量应用化学除草剂。结果表明:互作效应与物质的种类、浓度水平与比例密切相关。125 mg.L-1酚酸类化感物质与丁草胺混用,阿魏酸、对羟基苯甲酸和水杨酸对丁草胺表现增效作用,而香豆酸与丁草胺混用则为加成作用;500 mg.L-1阿魏酸和水杨酸与丁草胺混用表现加成作用,而500mg.L-1对羟基苯甲酸和香豆酸与丁草胺混用则产生拮抗作用。酚酸类化感物质与丁草胺等比例混用,水杨酸对丁草胺产生增效作用,其余3种物质对丁草胺表现加成作用。125 mg.L-1水杨酸、阿魏酸和对羟基苯甲酸与丁草胺混用后对稗草的抑制效果分别为丁草胺抑制效果的1.23、1.11和1.02倍,丁草胺与香豆酸混用处理的抑制效果稍微降低,为丁草胺单独应用抑制稗草效果的81%。

黑龙江省稻稗对二氯喹啉酸敏感性研究

利用滤纸法、琼脂法、整株生测法测定黑龙江省10个不同采集点稻稗种子对二氯喹啉酸的敏感性。结果表明,供试10个采集点均未产生明显抗性。其中,852农场采集点稻稗对二氯喹啉酸处于敏感性下降阶段,测得抗性指数分别为4.11、4.82、4.39;五常拉林采集点稻稗对二氯喹啉酸均最敏感;其他采集点稻稗对二氯喹啉酸敏感性介于二者之间。

旱稻×稗草远缘杂交研究

以旱稻基因型旱65为母本,稗草长芒稗为父本,通过杂交、回交技术,导入稗草高光效、速生快长基因,效果非常明显。

稗草对7种除草剂的敏感性及其生物测定方法的研究

应用滤纸法研究不同处理时间稗草(Echinochloa crusgalli)对7种除草剂的敏感性,并比较了稗草在滤纸法、琼脂法和盆栽喷雾法中对二氯喹啉酸的灵敏度,并应用琼脂法测定了7种除草剂的敏感性。结果表明:吡嘧磺隆(pyrazosulfuron-ethyl)以2 d的EC50值最低;五氟磺草胺(penoxsulam)、丙炔草酮(oxadiargyl)、二氯喹啉酸(quinclorac)和扑草净(prometryn)则以3 d的结果为最好;四唑酰草胺(fentrazamide)和嗪草酮(oxaziclomefone)以4 d的结果为最敏感。3种生物测定方法中稗草对二氯喹啉酸的敏感性以琼脂法为好,能达到快速、灵敏的目的。7种除草剂的敏感性大小(根据EC50值)顺序为:嗪草酮>四唑酰草胺>丙炔草酮>二氯喹啉酸>五氟磺草胺>吡嘧磺隆>扑草净。

水稻田除草剂三唑磺草酮的作用特性

为了明确水稻田除草剂三唑磺草酮(QYR301)的最佳施药条件,以稗草Echinochloa crus-galli和水稻Oryza sativa作为测试靶标,采用温室盆栽法研究了其施药适期、耐雨水冲刷性、温度和光照强度对其除草活性的影响。结果显示:三唑磺草酮对不同叶龄水稻具有较高的安全性,在有效成分360 g/hm^2的剂量下,对2叶期以后的水稻干重抑制率为0%;其除草活性与稗草的叶龄显著相关,其中2~3叶期的稗草最为敏感,有效成分30 g/hm^2的三唑磺草酮对其干重抑制率为95%~98%;三唑磺草酮具有一定的耐雨水冲刷能力,药后降雨间隔达到8 h以上,其除草活性与药后降雨间隔时间无显著相关性,在有效成分30~120 g/hm^2的剂量下,对稗草的干重抑制率为75%~93%;在20~35℃区间,三唑磺草酮药效稳定,对稗草的GR50值在44.6~51.4 g/hm^2之间;相较于中度光照(45%)和低光照(4%),高光照(100%)条件下三唑磺草酮对稗草的干重抑制率显著增加。分析表明杂草叶龄、降雨、温度和光照会显著影响三唑磺草酮除草活性,为使其发挥最大药效,应选择在水稻2叶期以后至稗草2~4叶期,天气晴朗,气温高于20℃的情况下施药;如药后8 h以内遇降雨天气,则需进行补喷。

微生物除草剂禾长蠕孢菌孢子助剂筛选

禾长蠕孢菌(Helminthosporium gramineum)是一株杂草生防潜力菌,对稻田稗草有较强的致病作用,并对水稻等主要作物安全,其活性成分孢子有望开发成微生物除草剂产品。为此,文章以生物相容性、分散力和稳定性等评判指标开展了禾长蠕孢菌孢子助剂筛选研究。结果发现,SP-20为表面活性剂、大豆油为溶剂油、羧甲基纤维素钠为稳定剂时,与孢子的生物相容性较好,对菌丝生长和孢子萌发都没有显著抑制作用。且添加SP-20后,孢子悬浮液I值为0.094,对孢子粉的分散性最佳。添加羧甲基纤维素钠作为稳定剂时,拟合直线斜率最小,为0.232,因此稳定性最好。以上助剂筛选结果将为禾长蠕孢菌孢子制剂的开发及其应用奠定基础。