转基因耐除草剂玉米ZZM030对草铵膦、草甘膦及非靶标除草剂的耐受性评价

采用田间试验,鉴定小区随机区组排列,对转基因玉米ZZM030和对应的非转基因对照祥249进行不同用量的草甘膦、草铵膦及非靶标除草剂的喷施处理,分别在用药后7、14、28 d调查和记录成苗率、植株高度、药害症状,评价该转基因玉米品系的目标性状有效性和对非靶标除草剂耐受性。结果表明,转基因玉米ZZM030对草铵膦和草甘膦具有良好的耐受性,对玉米田其他常用除草剂阿特拉津和烟嘧磺隆也具有良好的耐受性,不耐受玉米敏感型除草剂精喹禾灵和稀禾啶。     

除草剂、杀菌剂的选择及药害的补救

１除草剂的选择近十年来，黑龙江省农垦总局植保站组织农药联网试验，对除草剂安全性进行系统评价，结论是水稻除草剂安全性直接影响水稻产量和品质。防除稗草最安全的是禾大壮、千金，其次是杀草丹、拜田净、瑞飞特、阿罗津、苯噻草胺、农思它、快杀稗，最差的是丁草胺。防阔叶杂草的除草剂最安全的是草克星（草灭草、草威、吡嘧磺隆）、农得时、威农、金秋、太阳星、排草丹，最差的是２甲４氯及２甲４氯的混剂。应注意９０％杀草丹乳油适用于南方、北方旱育苗床封闭除草用５０％杀草丹乳油安全有效。垦区属寒温带大陆性气候，其中五至六月…     

草铵膦在转基因抗除草剂杂交稻培中的应用效果研究

随着劳动力成本的不断提高和水稻耕作方式的革新,如何高效防除杂草成为当前水稻栽培中亟待解决的重要问题,转基因抗除草剂杂交稻的培育成功为此提供了重要途径.中国科学院亚热带农业生态研究所水稻组经过十多年的研究,成功培育了具有灭生性除草剂草铵膦抗性的“香125S/Bar68 -1”和“株1S/Bar68 -1”等多个转基因抗除草剂杂交稻组合,并进入到生产性试验阶段.近年来,课题组围绕草铵膦在转基因抗除草剂杂交稻大田栽培中的应用开展了系列研究,获得如下主要结果:(1)以转基因抗除草剂杂交稻“香125S/Bar68 -1”和常规杂交稻“株两优819”为材料,采用直播、抛秧和手插3种栽培方式,设置草铵膦除草、常规1次除草和不除草3种除草处理,初步探讨草铵膦除草剂的应用效果.结果表明:草铵膦除草剂对“香125 S/Bar68 -1”的直播、抛秧和手插3种栽培方式稻田中的杂草防除效果均比常规除草剂好,在直播栽培中的效果尤为显著.“香125S/Bar68 -1”在各处理间的主要经济性状表现优势为:抛秧和手插田草铵膦除草＞直播田草铵膦除草＞抛秧和手插田常规除草＞直播田常规除草.(2)以转基因抗除草剂杂交稻“株1 S/Bar68 -1”为材料,常规除草剂2次除草方式为对照,比较了草铵膦除草剂1次除草方式在直播栽培中的应用效果.结果表明:与常规除草相比,草铵膦除草对供试材料株叶形态无明显影响,但使田间杂草数量(主要为千金子)减少577％,同时显著增加了有效穗数和直链淀粉含量,极显著增加了千粒重,实际增产49.4％,节约成本37.5％.(3)以转基因抗除草剂杂交稻“香125S/Bar68 -1”为材料,常规除草剂2次除草方式为对照,比较了草铵膦除草剂1次除草方式在抛秧栽培中的应用效果.结果表明:草铵膦除草处理区杂草茎数(主要为双穗雀稗)仅为常规除草剂处理区的11.7％,实际增产12％,节约成本42％.(4)以转基因抗除草剂杂交稻组合“株1 S/Bar68 -1”为材料,采用草铵膦除草剂1次除草的除草方式,进行了手插和抛秧的栽培示范研究.结果表明,草铵膦1次除草效果良好,手插和抛栽区基本无可见杂草,手插栽培产量和有效穗数均比抛秧栽培高5.2％,但差异不显著.综合上述研究结果初步提出了转基因抗除草剂杂交稻栽培中应用草铵膦1次除草的技术要点为:草铵膦有效成分浓度0.6 g/L,每公顷用量480 ～ 960 L(有效成分剂量288～ 576 g/hm2),于分蘖盛期或末期(视杂草发生情况而定)紧挨冠层均匀喷雾,冒头杂草重点喷施.同时认为开展培育矮秆少蘖的转基因抗除草剂杂交稻应用于直播栽培研究、大田应用草铵膦同时除草除杂技术研究和草铵膦施用浓度及喷施技术研究等,将能进一步发挥转基因抗除草剂杂交稻的巨大优势.     

除草剂炔草酯对不同小麦品种幼苗期叶片抗氧化特性的影响

为了解小麦品种对除草剂炔草酯的耐性与抗氧化特性的关系,采用盆栽试验方法,以对除草剂敏感型品种宁麦16、中度敏感型品种扬麦15和耐药型品种淮麦23为材料,测定了炔草酯制剂处理后三个品种幼苗叶片MDA含量、叶绿素含量、SOD、POD和GSTs活性的变化。结果表明,炔草酯120mg·L-1处理15d后,宁麦16药害最重,MDA含量增加了56.41%,叶绿素含量下降了68.58%,SOD、POD和GSTs活性分别上升130.75%、123.06%,和23.33%;扬麦15叶片MDA含量增加32.05%,叶绿素含量和SOD活性无显著变化,POD和GSTs活性提高29.77%和28.30%;淮麦23叶片MDA含量、叶绿素含量和GSTs活性无显著变化,SOD和POD活性分别增加了225.96%和63.87%。当药剂浓度为240mg·L-1时,淮麦23叶片GSTs活性提高了41.11%,增幅高于宁麦16(16.67%)及扬麦15(23.58%)。说明敏感性不同的小麦品种对炔草酯的反应在抗氧化特性上存在明显差异,耐药型品种可能通过较高的抗氧化能力减轻除草剂的胁迫伤害。     

4种茎叶处理除草剂对不同生育时期田旋花的防除效果

为筛选有效防控棉田田旋花的除草剂,采用室内生测法研究了草甘膦、草铵膦、三氟啶磺隆钠盐、丙炔氟草胺4种茎叶处理除草剂对不同生育时期田旋花的防除效果。结果表明：4种除草剂对田旋花的防效依次为草铵膦＞三氟啶磺隆钠盐＞丙炔氟草胺＞草甘膦,且应在田旋花3～4叶期前进行防除。田旋花生长至7～8叶期时,可优选草铵膦进行防除,既可杀死杂草地上植株,又可抑制田旋花地下根茎的再生。     

安徽沿江棉区除草剂使用中的问题及对策

安徽沿江棉区以种植棉花、油菜、小麦为主，一般为两熟制。在当地广泛使用的除草剂类型主要有：（1）灭生性除草剂有10％草甘膦、62％草甘膦、40％草甘膦、百草枯等；（2）阔叶除草剂有苯磺隆、乙羧氟草醚、二甲四氯等；（3）禾本科除草剂有高效盖草能、精奎禾灵；（4）芽前除草剂有乙草胺、金都尔、床草净、野老等。灭生性除草因省工省时、除草效果好，备受农户青睐，在棉花生产中至少使用2次，即移栽棉花前使用一次，封行前再使用一次。     

油菜抗除草剂机理与种质创制研究进展

杂草是制约油菜生产的重要生物灾害之一,严重影响油菜的产量和品质。培育抗除草剂油菜品种是防除油菜田间杂草的经济、有效的途径。本文综述了已被广泛应用的草甘膦、草铵膦和ALS酶抑制类除草剂的作用机理、植物对除草剂产生抗性的机制以及国内外这三类油菜抗性种质的创制和研究进展,并提出了油菜抗除草剂种质的发展策略,加强抗性机制研究和基因的发掘力度,利用基因编辑等新技术创制抗除草剂油菜新种质,培育具有多种除草剂抗性的油菜新品种。     

水稻机插秧“插喷同步”封闭除草技术及配套除草剂防效对比

采用机插秧“插喷同步”技术,于2019年开展大田试验,分别施用4种除草剂（33%嗪吡嘧磺隆、19%氟酮磺草胺、25%双环磺草酮、300 g/L丙草胺+10%苄嘧磺隆）进行除草,对比各除草剂处理对水稻的安全性及对稻田杂草的防治效果。结果表明,药后水稻均未发生可见药害,参试除草剂安全性好;药后35 d供试除草剂对试验田总草防效达95.0%以上;与施用除草剂处理相比,未施药对照水稻产量损失严重,减幅12.5%~42.7%。可见,“插喷同步”技术是一种高效除草技术,供试4种除草剂均能有效防治杂草,降低除草成本,提高种稻效益。     

棉田生杂草如何防除好

近日来,本地很多棉农反映棉田杂草丛生,想使用除草剂防治,但一些除草剂的说明书上的杂草名称和地里的杂草“对不上号”,不知如何使用除草剂?对此,笔者解答如下。1杂草种类识别1.1一年生禾本科杂草。马唐(抓地草、拉秧草),牛筋草(蟋蟀草、半大墩),狗尾草(谷莠子、野谷苗),看麦娘(棒槌草),虎尾草(棒槌草、刷子头),蜱草(扁扁草),千金子(绣花草),画眉草(星星草)等。1.2多年生禾本科杂草。狗牙根(爬根草、护堤草),白茅(茅草、茅根),芦苇(苇子草、芦柴)等。1.3一年生阔叶杂草。马齿苋(马齿菜)、藜(灰灰菜)、反枝苋(英英菜、野苋菜),龙葵(野葡萄、…     

几种蔗田化学除草剂防效初报

通过对蔗草净、灭草威、玉米、阿特拉津加乙草胺４种除草剂防除蔗田杂草效果研究表明：４种度除草剂防除效果均较好,但以玉丰每公顷３０００ｍｌ用量的效果最佳,且持效期长,对甘蔗幼苗无药害,除草成本低,使用方便,是取代阿特拉津加乙草胺的理想除草剂。     

Weed management in no-till winter wheat (Triticum aestivum L.)

In general, effective weed control in no-tillage systems is based on the use of herbicides. However, the development of appropriate weed management strategies can help to reduce the amount of herbicides applied.     

Yield loss prediction models based on early estimation of weed pressure

Weed control thresholds have been used to reduce costs and avoid unacceptable yield loss. Estimation of weed infestation has often been based on counts of weed plants per unit area or measurement of their relative leaf area index. Various linear, hyperbolic, and sigmoidal regression models have been proposed to predict yield loss, relative to yield in weed free environment from early measurements of weed infestation. The models are integrated in some weed management advisory systems. Generally, the recommendations from the advisory systems are applied to the whole field, but weed control thresholds are more relevant for site-specific weed management, because weeds are unevenly distributed in fields. Precision of prediction of yield loss is influenced by various factors such as locations, yield potential at the site, variation in competitive ability of mix stands of weed species and emergence time of weeds relative to crop. The aim of the review is to analyze various approaches to estimate infestation of weeds and the literature about yield loss prediction for multispecies. We discuss limitations of regression models and possible modifications to include the influential factors related to locations and species composition in context of their implementation in real time patch spraying.     

A model to simulate yield losses in winter wheat caused by weeds,for use in a weed management decision support system

The ‘within-season’ module of the Weed Manager decision support system (DSS) predicts the effect of twelve UK arable weeds on winter wheat yields and profitability. The model and decision algorithm that underpin the DSS are described and their performance discussed. The model comprises: (i) seedling germination and emergence, (ii) early growth, (iii) phenological development, (iv) herbicide and cultivation effects and (v) crop yield loss. Crop and weed emergence are predicted from the timing and method of cultivation, species biology, and the weather. Wheat and weeds compete for resources, and yield losses are predicted from their relative leaf area at canopy closure. Herbicides and cultural control methods reduce weed green area index, improving crop yield. A decision algorithm identifies economically successful weed management strategies based on model output. The output of the Weed Manager model and decision algorithm was extensively validated by experts, who confirmed the predicted responses to herbicide application were sufficiently accurate for practical use. Limited independent data were also used in the validation. The development of the module required integrating novel and existing approaches for simulating weed seedling establishment, plant development and decision algorithm design. Combining these within Weed Manager created a framework suitable for commercial use.     

Effect of herbicide application on weed flora under conservation agriculture in Zimbabwe

Increased challenges of weed control in the smallholder farming sector of southern Africa have often resulted in small yields. The objective of this study was to evaluate the effects of different weed control strategies on weed flora and composition under conservation agriculture (CA) systems in Zimbabwe. This study was conducted at three on-station trial sites namely Domboshawa Training Centre (DTC), University of Zimbabwe farm (UZ farm) and Henderson Research Station (HRS) in a maize–soybean rotation for four seasons from 2009–2010 to 2012–2013 seasons. Hand weeding was done whenever weeds were 10 cm tall or 10 cm in circumference for weeds with a stoloniferous growth habit. Weed identification was done up to the weed species level, and the Shannon–Weiner diversity and evenness index was used to determine the response of weed flora to herbicides. Results showed that there were more weeds in the early years which decreased gradually until the final season. Weed species diversity was not affected by herbicide application and the results indicated that weed species diversity was small in CA systems. Annual weed species constituted a greater proportion of species, and species richness decreased with the duration of the study. Richardia scabra L. and Galinsoga parviflora Cav. were the most common dominant weed species at all sites and in all seasons. Moreover, herbicide application had no effect on the evenness of weeds in the plots but site characteristics had a significant effect on the distribution of weed species (weed species evenness). The results presented in this study suggest that herbicide application facilitates a depletion of weed seed bank/number of weeds over time. Thus, herbicide application in CA has potential to reduce weed density, species richness and species diversity in the long term which may lead to more labour savings and larger yields.     

Sustainable weed management in conservation agriculture

Sustainable crop production is necessary to ensure global food security and environmental safety. Conservation agriculture (CA) is gaining popularity around the globe due to its sustainable approaches such as permanent soil cover, minimal soil disturbance, planned crop rotations and integrated weed management. Weed control is the biggest challenge to CA adoption. Weed ecology and management is different in CA than in conventional agriculture. In CA, weeds expression, seed bank status, distribution, dispersal mechanisms, diversification, growing patterns and competition trends are complex and differ from conventional systems. It is due to reduced tillage of the soil and the flora that thrives in CA. Reduced tillage systems affect the efficacy of herbicides and mechanical weed control measures. So, it is an important task to find out the differences and to fabricate new management options. In this review, changing weed dynamics have been framed. A novel aspect of this review is the comprehensive account of sustainable weed management strategies in relation to CA. Modified tillage operations, improved cultural practices, bioherbicides, chemical herbicides, allelopathy, and crop nutrition have been identified as suitable weed management tools. None of these offers complete control but the integration of these tools in suitable combinations works efficiently. Weeds dominating CA and their responses to CA components are highlighted. For example, small seeded and perennial weeds are more abundant in CA. The role of herbicide resistance in weeds and herbicide tolerant (HT) crops in CA is also highlighted. Allelopathy and crop nutrition are discussed as modern weed management tools for CA. A detailed account of weed responses to fertilizer management options is also given. Integrated weed management compatible to cropping patterns and climatic conditions offers the best results in CA. Future efforts must be directed towards the optimization and integration of these weed management practices.     

Biology,impact, and management of Echinochloa colona (L.) Link

Echinochloa colona (L.) Link. is one of the most problematic weeds across the world. It is an annual C₄ summer grass, native to tropical and subtropical Asia, emerged as a serious and persistent threat in 35 cropping systems in more than 60 countries. E. colona is reported as an important associated weed species in transplanted and direct-seeded rice. Diverse ecotypes, high seed production, short seed dormancy, rapid growth, competitive potential, allelopathic interaction, and resistance against several herbicides makes it a more adaptable and persistent challenge in various agro-ecosystems. Development of resistance to recommended or higher doses of numerous herbicides, including ametryn, atrazine, bispyribac-sodium, clefoxidym, cyhalofop-butyl, fenoxaprop-p-ethyl, glyphosate, metribuzin, propanil, and triazine, is a serious concern for the farming and scientific community. Crop infestation with resistant E. colona biotypes may ultimately increase the weed control cost. Unfortunately, investigations on seed dormancy release, genetic diversity, allelopathic interference, and competitive ability of this weed are inadequate in accomplishing its appropriate control in different environments. Therefore, a comprehensive review is presented here to gather the existing information, to pin point key findings, and to highlight the research gaps in the biology, interference, and management of E. colona. Different management options have been discussed in relation with eco-biology of this noxious weed. The potential research endeavours have also been highlighted in order to provide an insight of its existing scenario and to facilitate the future management strategies.     

The critical period for weed control in dry-seeded rice

The critical crop-weed competition period in a dry-seeded rice system is an important consideration in formulating weed management strategies. Field experiments were conducted in the summer seasons of 2012 and 2013 at the Punjab Agricultural University, Ludhiana, India, to determine the extent of yield loss in two different rice cultivars (PR 114 and PR 115) with different periods of weed interference. Twelve weed control timings were used to identify critical periods of weed competition in dry-seeded rice. PR 114, a long-duration rice cultivar (145 d) having slower initial growth than PR 115 (125 d), was more prone to yield losses. In both years, 100% yield loss was observed where weeds were not controlled throughout the season. In weed-free plots, the grain yield of PR 114 was 6.39–6.80 t ha⁻¹, for PR 115, it was 6.49–6.87 t ha⁻¹. Gompertz and logistic equations fitted to yield data in response to increasing periods of weed control and weed interference showed that, PR 114 had longer critical periods than PR 115. Critical weed-free periods to achieve 95% of weed-free yield for PR 114 was longer than for PR 115 by 31 days in 2012 and 26 days in 2013. Weed infestation also influenced the duration of critical periods. Higher weed pressure in 2012 than in 2013 increased the duration of the critical period of crop-weed competition in that year. The identification of critical crop-weed competition periods for different cultivars will facilitate improved decision-making regarding the timing of weed control and the adoption of cultivars having high weed-suppressing abilities. This will also contribute to the development of integrated weed management in dry-seeded rice systems.     

Effects of water regime,nitrogen fertilization,and rice plant density on growth and reproduction of lowland weed Echinochloa crus-galli

Direct-seeded rice systems are increasing in Asia as farmers respond to the high labor cost and shortage of water. Echinochloa crus-galli is one of the most problematic and competitive weeds in direct-seeded rice systems. Because of concerns about excessive herbicide use, there is an interest in developing cultural weed management strategies. However, the design of such strategies requires a better understanding of the weed response to crop density, nutrition, and water regime. A study was therefore conducted in pots to determine the effect of water (flooded and aerobic), nitrogen (N) fertilization (0, 100, and 200 kg N ha⁻¹), and rice density [0, 4 rice plants (≈20 kg seed ha⁻¹), and 16 rice plants (≈80 kg seed ha⁻¹)] on the growth and reproduction of E. crus-galli. When grown alone, the growth and seed production of E. crus-galli were higher in flooded conditions than in aerobic conditions. However, no such differences were observed when E. crus-galli was grown with rice interference. E. crus-galli growth and seed production increased with increases in N rate. Irrespective of water regime and N rate, the growth and seed production of E. crus-galli declined with increases in rice density. At 100 kg N ha⁻¹, for example, E. crus-galli shoot biomass and seed production decreased by 84–86% and 82–87%, respectively, when grown with 16 rice plants compared with its growth without rice interference. The results suggest that growth and seed production of E. crus-galli can be greatly reduced by increasing rice seeding rate. However, there is a need to involve other weed management strategies to achieve complete control of E. crus-galli and other weed species.     

Growth and weed suppression ability of common and new cover crops in Germany

Cover crops have a wide-ranging influence on the agroecosystem and create multiple benefits for farmers. A major benefit of cover crops is the suppression of weeds during fall and winter, which can help to reduce soil tillage and herbicide use. However, only a small number of cover crop species are currently grown in Germany. To enlarge this number, four new cover crop species including tartary buckwheat, forage radish, red oat and grain amaranth were tested in comparison with common cover crop species such as white mustard, oilseed radish and phacelia. Emergence, soil coverage, dry matter production and weed suppression ability was assessed for all cover crop species. White mustard emerged faster than all other cover crops and produced the highest amount of shoot dry matter at both locations in southwest Germany twelve weeks after planting (WAP). Oilseed radish was the only cover crop that reduced the weed dry matter in all experiments eight WAP. Phacelia was able to reduce weed density by 77% at Meiereihof twelve WAP. Tartary buckwheat offered the highest soil coverage four WAP, produced the greatest shoot dry matter eight WAP and reduced weed dry matter by more than 96% at Meiereihof and Ihinger Hof twelve WAP. Forage radish produced the highest root dry matter and reduced spring weed density by more than 81% in all experiments. Red oat and grain amaranth emerged slowly, produced less biomass than other cover crops and did not suppress weed growth. The results show that tartary buckwheat and forage radish are well suited as new cover crops in Germany due to their fast growth and good weed suppression ability.     

江苏金坛水稻田杂草发生危害调查研究

为揭示江苏金坛稻麦轮作制水稻田杂草组成、发生等危害特点,于2014年10月调查不同区域、不同管理措施的90块水稻田。结果显示:金坛地区水稻田有12科21属23种杂草,其中外来入侵杂草2种;优势杂草种为鸭舌草(Monochoria vaginalis)、水苋菜(Ammannia baccifera)、稗草(Echinochloa crusgalli)、千金子(Leptochloa chinensis)、陌上菜(Lindernia procumbens)、多花水苋(Ammannia multiflora)。