Identification of the mutation responsible for resistance to QoI fungicides and its detection in Ascochyta rabiei (teleomorph Didymella rabiei)

This study characterized a fragment of the cytochrome b gene from Ascochyta rabiei isolates collected in North Dakota, USA, that varied in sensitivity to quinone‐outside inhibitor (QoI) fungicides. The sequenced genomic DNA fragment contained a group I intron immediately after codon 131. The size of the cytochrome b gene was estimated to be over 4·6 kb. Multiple alignment analysis of cDNA and protein sequences revealed a mutation that changed the codon for amino acid 143 from GGT to GCT, introducing an amino acid substitution from glycine to alanine (G143A), which is frequently associated with QoI resistance. Based on this mutation, a diagnostic PCR assay was developed using an approach called mismatch amplification mutation assay. This method was successfully validated by testing a total of 70 A. rabiei isolates, of which 38 isolates were found to be QoI‐resistant. This fast and accurate PCR assay provides a very useful and simple screening method for QoI resistance in A. rabiei isolates.     

Mutations in sdh genes in field isolates of Zymoseptoria tritici and impact on the sensitivity to various succinate dehydrogenase inhibitors

Zymoseptoria tritici is the causal agent of septoria tritici blotch (STB), a foliar wheat disease important worldwide. Succinate dehydrogenase inhibitors (SDHIs) have been used in cereals for effective control of STB for several years, but resistance towards SDHIs has been reported in several phytopathogenic fungi. Resistance mechanisms are target‐site mutations in the genes coding for subunits B, C and D of the succinate dehydrogenase (SDH) enzyme. Previous monitoring data in Europe indicated the presence of single isolates of Z. tritici with reduced SDHI sensitivity. These isolates carried mutations leading to amino acid exchanges: C‐T79N, C‐W80S in 2012; C‐N86S in 2013; B‐N225T and C‐T79N in 2014; and C‐V166M, B‐T268I, C‐N86S, C‐T79N and C‐H152R in 2015. The current study provides results from microtitre and greenhouse experiments to give an insight into the impact of different mutations in field isolates on various SDHIs. In microtitre tests, the highest EC₅₀ values for all tested SDHIs were obtained with mutants carrying C‐H152R. Curative greenhouse tests with various SDHIs confirmed the findings of microtitre tests that isolates with C‐H152R are, in general, controlled with lower efficacy than isolates carrying B‐T268I, C‐T79N and C‐N86S. SDHI‐resistant isolates of Z. tritici found in the field were shown to have cross‐resistance towards all SDHIs tested. So far, SDHI‐resistant isolates of Z. tritici have been found in low frequencies in Europe. Therefore, FRAC recommendations for resistance management in cereals, including a limited number of applications, alternation and combination with other MOAs, should be followed to prolong SDHI field efficacy.     

Effect of azole fungicide mixtures,alternations and dose on azole sensitivity in the wheat pathogen Zymoseptoria tritici

The evolution of fungicide resistance in the cereal pathogen Zymoseptoria tritici is a serious threat to the sustainability and profitability of wheat production in Europe. Application of azole fungicides has been shown to affect fitness of Z. tritici variants differentially, so it has been hypothesized that combinations of azoles could slow the evolution of resistance. This work assessed the effects of dose, mixtures and alternations of two azoles on selection for isolates with reduced sensitivity and on disease control. Naturally infected field trials were carried out at six sites across Ireland and the sensitivity of Z. tritici isolates monitored pre‐ and post‐treatment. Epoxiconazole and metconazole were applied as solo products, in alternation with each other, and as a pre‐formulated mixture. Full and half label doses were tested. Isolates were partially cross‐resistant to the two azoles, with a common azole resistance principal component accounting for 75% of the variation between isolates. Selection for isolates with reduced azole sensitivity was correlated with disease control. Decreased doses were related to decreases in sensitivity but the effect was barely significant (P = 0·1) and control was reduced. Single applications of an active ingredient (a.i.) caused smaller decreases in sensitivity than double applications. Shifts in sensitivity to the a.i. applied to a plot were greater than to the a.i. not applied, and the decrease in sensitivity was greater to the a.i. applied at the second timing. These results confirm the need to mix a.i.s with different modes of action.     

小麦品种多样性对白粉病及产量和蛋白质的影响

 对品种多样性控制小麦白粉病的效果以及对产量和蛋白质的影响进行了研究,为利用品种多样性控制白粉病提供理论依据和技术支持。采用SSR技术分析5个小麦品种的亲缘关系;2008年和2009年按组合所含品种数为2、3、4和5个进行组合,在田间种植混种组合和单播小区,人工接种白粉菌,比较各小区中小麦白粉病的AUDPC值、产量和蛋白质变化。结果表明,5个品种亲缘关系相对较近;2个品种混合时以抗感搭配较好,随着抗病品种比例增加控病效果增强;2008年混合种植中有防治效果的组合占54.55%,相对防效为10.02%~47.58%,2009年有防治效果的组合占23.08%,相对防效在1.85% 到18.96 % 之间;在适当的组合中,如京冬8号/轮选987、京双16/京411/京冬8号对小麦白粉病有控制效果,混种不会影响产量和蛋白质含量;当有大量能克服本地品种抗性的外来菌源时混合种植的控病效果降低。品种多样性可以用做防治小麦白粉病的一项措施。     

不同耕作方式对冬小麦光合作用产量和水分利用效率的影响

豫西旱地大田条件下,对一次深翻、免耕覆盖、深松覆盖、传统耕作4种耕作方式冬小麦叶面积指数、旗叶光合特性、干物质积累与分配及小麦产量和水分利用效率进行试验分析.结果表明,在小麦生育后期,深松覆盖和免耕覆盖能有效延缓小麦旗叶叶绿素降解,维持较高的叶面积指数,改善旗叶光合性能,促进干物质积累,产量分别比传统耕作提高9.26%和10.22%,水分利用效率分别比传统耕作提高10.29%和15.57%.与传统耕作相比,深松覆盖灌浆中后期旗叶光合速率提高了5.48%,Fv/F0值提高了26.72%,Fv/F3m值提高4.88%,ψPSⅡ值和1-qP/qN值与其它耕作方武相比差异不显著.     

不同栽培模式和施氮对半湿润易旱区冬小麦籽粒灌浆特征的影响

在黄土高原南部半湿润易旱区,以土垫旱耕人为土为供试土壤,进行大田试验,研究栽培模式和施氮对冬小麦灌浆过程中籽粒体积、粒重和含水量的影响.结果表明,籽粒体积随灌浆进程的麦化符合一元二次方程,籽粒体积在灌浆起始阶段快速增长,之后缓慢增长至最大值,后期快速下降;对不同灌浆期籽粒体积和最大籽粒体积,小偃22大干小偃503,不同栽培模式其大小顺序为:集雨面栽培＞全程覆膜＞常规栽培,施氮对其影响不显著,各处理达到最大籽粒体积时间变化在24.3～25.7 d间,差异不大.各处理粒重均呈"S"型变化趋势,符合Logistic 生长模型;小偃22的最大粒重大干小偃503;而不同栽培模式的最大粒重表现为:地膜覆盖栽培＞常规栽培、集雨面栽培;施氮对小偃503最大粒重有促进作用,而对小偃22表现出一定抑制作用.从总体上看,小偃503的灌浆速率大干小偃22;常规栽培和集雨面栽培的灌浆速率大于覆膜栽培;施氮对灌浆速率的影响与对粒重的影响相反.不同小麦品种粒重的差异与灌浆进程有关,在灌浆前期小偃22与小偃503粒重差异不明显,在中后期,小偃22与小偃503粒童差异逐渐增大,灌浆结束时小偃22粒重显著大干小偃503.从收获时粒重和全灌浆期平均粒重看,均以集雨面栽培最大,全程覆膜栽培次之,常规栽培最小,与最大粒重有所不同.籽粒含水量随灌浆过程推进几乎均呈直线下降,但小偃22籽粒含水量大干小偃503;栽培模式和施氮对籽粒含水量影响较小.小麦粒重与籽粒体积和含水量间存在显著或极显著线性相关关系.     

Some effects of plant densities and carbofuran on the damage by Diopsis thoracica West,and Maliarpha separatella Rag. and yield of rice in Nigeria

Abstract

In a field study of the effects of plant densities and carbofuran on damage by Diopsis thoracica Westwood and Maliarpha separatella Ragonot, significant increases were recorded in the percentage of dead hearts and bored stems in widely spaced rice plants. Carbofuran treatments resulted in significant control of borers, the best treatment being that covering early growth up to 40 days after transplanting. There was a significant depression of yield components and total yield with closer spacing. Yield increases of 59%, 32% and 55% for the 1983 planting, and 55%, 35% and 50% for the 1984 planting, were recorded when carbofuran was applied to cover the periods 0 to 40, 40 to 80, and 0 to 80 days after transplanting, respectively.The percentage of dead hearts and bored stems increased with increasing seedling density. The yield components, however, did not show any significant differences.     

动植检查验基础保障平台的开发与应用

随着国际贸易往来和人员交流快速增长,国门生物安全形势日趋严峻,这对我国口岸动植检规范化建设提出了更高要求。为更有效地推动口岸动植检规范化建设,亟需掌握全系统口岸动植检技术设施、专业队伍、人员素质等要素建设现状和需求。本文基于应用信息化手段提升工作效率、全盘掌握建设现状、即时统计数据分析、为科学决策提供依据等理念,设计研发了"动植检查验基础保障平台"系统。推广应用该系统将显著提升全国口岸动植检规范化建设管理的系统性和科学性。     

免耕覆盖对春小麦灌浆期干物质积累特性及最终产量的影响

以常规耕作处理作对照,研究了免耕覆盖下春小麦灌浆期间干物质积累分配特性和产量变化,结果表明,高、低秸秆覆盖量下春小麦灌浆期间干物质积累量比常规耕作分别高16.1%、9.8%,免耕秸秆覆盖为春小麦籽粒和产量形成提供了更充足的物质来源;与常规耕作比,免耕覆盖处理的春小麦在花后21-28 d时干物质积累量有个快速增加阶段;在干物质的运转分配中,免耕覆盖对春小麦灌浆期积累的干物质在各个器官间的分配比例影响较小。相对于常规耕作而言,免耕秸秆覆盖处理提高了春小麦产量,其产量的增加主要依赖于花前光合产物的积累,对花后光合产物调用较少。低覆盖量下春小麦较常规耕作增产11.68%,高量覆盖较常规增产18.52%。     

不同植物生长调节剂对新疆棉花干物质积累、产量和品质的影响

通过大田试验研究了3种不同的植物生长调节剂及其施用方法对棉花干物质积累特性以及品质和产量的影响效应.试验设计为叶面喷施缩节胺、随水滴施多效唑、随水滴施促根剂和随水滴施多效唑+促根剂.结果表明:不同的化控处理棉株干物质积累均随生育期延长而持续增加,动态变化可用"S"曲线方程拟合.干物质积累速率呈单峰曲线变化,峰值出现在出...     

胺鲜酯对甜玉米叶片光合特征、籽粒糖分积累和产量的调控效应

以甜玉米金玉甜1号为试验材料,于吐丝期叶面喷施胺鲜酯(DTA-6),研究其对甜玉米叶片光合特征、籽粒粒重、糖分积累、光合作用关键酶磷酸烯醇式丙酮酸羧化酶(PEPCase)和核酮糖二磷酸羧化酶(Ru BPCase)及蔗糖代谢相关酶蔗糖磷酸化酶(SPS)和蔗糖合成酶(SS)活性动态变化的调控效应。结果表明:DTA-6处理显著提高了甜玉米籽粒灌浆期穗位叶叶绿素含量和光合速率,改善了PEPCase和Ru BPCase的活性;DTA-6处理显著促进了籽粒SPS和SS活性表达,处理后12 d籽粒中可溶性糖、蔗糖和淀粉含量比对照分别增加了8.4%、8.8%和8.9%;DTA-6处理显著促进了籽粒灌浆速率,提高了穗粒数和粒重,增加了产量,其中鲜穗产量、穗粒数和千粒重比对照分别增加了15.8%、9.6%和11.9%。研究结果证实,DTA-6可以显著改善甜玉米产量和品质形成,为其在甜玉米高产优质栽培中推广应用提供了理论依据。     

喷施组合型生长调节剂对不同品种小麦冬前分蘖和生长及抗寒性的影响

采用大田随机区组试验,比较研究了一种已获得国家发明专利的组合型生长调节剂对不同冬小麦品种（西农979、西农889、郑州831和小偃22）冬前分蘖和生长以及抗寒性的影响。结果表明：在播种后一个半月喷施该生长调节剂能显著提高西农979、西农889及郑州831的冬前分蘖数和地上生物量,但对小偃22的分蘖数和生物量没有显著影响; 与未喷施生长调节剂的对照植株相比,在一年中最寒冷的时间,喷施生长调节剂的西农979叶片中叶绿素、类胡萝卜素、可溶性糖和淀粉、可溶性蛋白质和脯氨酸含量以及SOD和POD活性均显著提高,而丙二醛含量显著降低,但谷胱甘肽和抗坏血酸含量没有显著变化,表明喷施该组合型生长调节剂有助于提高西农979的抗寒性能;而对其余三个小麦品种而言,这些与植物抗寒性相关的生理生化指标未受到显著影响。对产量性状分析结果表明,喷施生长调节剂后,西农979、西农889和郑州831的单株成穗数分别提高了19.0％、17.8％和5.3％,单位面积产量分别提高了16.9％、16.2％和5.9％,但是小偃22的产量基本没有受到影响。说明该生长调节剂对不同品种冬小麦的冬前分蘖和生长、抗寒性及产量的效应不同,其中对西农979冬前分蘖和生长以及抗寒能力的提高、还有增产效果最明显,但对小偃22的效应不明显。     

陇东黄土旱塬不同耕作方式及施肥处理对冬小麦产量和土壤肥力的影响

在陇东旱塬覆盖黑垆土的土壤上,通过3年冬小麦田间试验研究了不同耕作方式及不同施肥处理对旱塬冬小麦产量、水分利用效率(WUE)和土壤肥力的影响。结果表明:传统深耕配施有机无机肥有利于作物高产和提高WUE;免耕年限增加不利于产量的增加;随着耕作年限的延长,传统耕作和免耕配施有机无机肥土壤有机质含量均有不同程度提高,传统耕作土壤有机质含量从试验前的11.75 g/kg提高到13.0 g/kg,提高了10.6%,免耕土壤有机质含量从试验前的11.75 g/kg提高到13.93 g/kg,提高了18.6%。从产量、WUE和土壤养分等方面综合分析,在陇东旱塬以传统深耕配施有机无机肥有利于增加作物产量,提高WUE,改善土壤肥力状况。因此,传统耕翻配施有机无机肥是目前陇东黄土旱塬培肥土壤和抗逆减灾最为有效的措施之一。     

The effects of foliar spray application of silicon on plant damage levels and components of larval biology of the pest butterfly Chlosyne lacinia saundersii (Nymphalidae)

We investigated sunflower leaf palatability to Chlosyne lacinia saundersii Doubleday & Hewitson (Lepidoptera: Nymphalidae) in plants treated with silicon (Si) and subjected to mechanical injury. We also examined the effects of those treatments on plant development. The experimental study was carried out as a completely randomized design, consisting of the six treatments (10 replicates each): (1) control, (2) plants mechanically injured, (3) Si applied around the plant stem (Si drench), (4) Si drench + injured, (5) Si drench + foliar spray, and (6) Si drench + foliar spray + injured. Si drench + injured significantly reduced the percentage of caterpillar-injured leaves (CIL), leaf area consumed (LAC), and caterpillar weight (CW), leading to increased caterpillar mortality. The only intrinsic plant characteristic affected by the treatments was Si content (SiC), which was higher in plants treated with either Si drench + foliar spray or Si drench + foliar spray + injured. Negative correlations were observed between SiC and the variables CIL, LAC and CW, whereas positive correlations were observed between CIL and LAC, CIL and CW, and LAC and CW. The treatment strategy of Si combined with artificial mechanical injury affects leaf palatability and development of C. lacinia saundersii, conferring resistance to sunflower plants as a function of Si accumulation, although it did not increase crop vegetative variables.     

不同水氮处理对滴灌冬小麦生长、产量和耗水特性的影响

通过滴灌小麦大田试验,研究了不同灌水下限(灌水下限为田间持水量的45%、60%、75%)和施氮处理(45、111、146 kg·hm~(-2))对田间冬小麦生长、产量和耗水特性的影响。结果表明:灌水下限对小麦株高、叶面积指数和干物质的影响是显著的,且比施氮量影响更大。W3(灌水下限为田间持水量45%)和N3(施氮量45 kg·hm~(-2))处理不利于小麦株高、叶面积的增长。在小麦生长后期,增加灌水量和施氮量有利于小麦株高的生长。小麦的产量随着灌水下限的增大而增加;施氮量在0~111 kg·hm~(-2)时,冬小麦产量随着施氮量的增加而增加,超过111 kg·hm~(-2)时不再显著增加甚至抑制产量的增长;灌水下限和施氮量相对较小的处理有利于提高水分利用效率。不同水肥处理,小麦各生育期内耗水量和耗水模数都表现为灌浆完熟抽穗扬花期拔节孕穗期返青起身期。在此试验条件下,W2N2的处理(灌水下限为田间持水量的60%,灌溉定额为290 mm,施氮量为111 kg·hm~(-2))的干物质、产量和水分利用效率最大,是产量和效益兼优的最佳组合。     

苜蓿斑蚜为害对5种苜蓿品种(系)PAL、POD、PPO酶活性的影响

在室内将苜蓿斑蚜人工接种在不同抗性级别的苜蓿品种（系）幼苗上,苜蓿斑蚜为害后的3、7、10 d分别测定了5个品种（系）叶片中苯丙氨酸解氨酶（PAL）、多酚氧化酶(PPO)、过氧化物酶（POD）3种酶活性。结果表明,在试验期内,所有品种（系）叶片中的PAL活性在接虫后随着时间的增加而升高; PPO活性随天数增加呈下降趋势; POD与PAL酶的情况相同,随着为害时间的延长不断升高。HA 3感蚜后3种酶活性明显高于其他品种。     

不同食料对人工饲养的二化螟生长发育和产卵量的影响

以浙江省 3种主栽水稻品种浙辐 910、杂交稻 (Ⅱ优 3027)、秀水 11的稻苗为供试食料喂饲二化螟 ,研究了 3种食料对二化螟生长发育和产卵量的影响。结果发现 ,3种食料对二化螟的存活率及性比影响较显著 ,对其发育历期的影响仅在低龄时有显著差异。不同的食料对二化螟蛹和成虫大小及产卵量的影响不大 ;在同样的食料条件下 ,不同性别间的发育历期差别不大 ,但二化螟蛹及成虫的大小在两性间差异显著 ,初蛹体重、体长以及成虫体重、体长 ,都是雌性极显著大于雄性     

三种杀螨剂对双尾新小绥螨后代生长发育和繁殖的影响

为明确杀螨剂对双尾新小绥螨Neoseiulus bicaudus后代生长发育及繁殖的影响,采用联苯肼酯、三唑锡和哒螨灵对土耳其斯坦叶螨Tetranychus turkestani的致死中浓度处理双尾新小绥螨雌成螨,测定其后代各发育阶段的存活率、发育历期、寿命、雌性比例及繁殖力,构建亚致死条件下双尾新小绥螨后代的年龄-龄期两性生命表并模拟其种群增长模型,分析不同杀螨剂亚致死效应对捕食螨后代的影响。结果表明,联苯肼酯处理能显著缩短双尾新小绥螨后代的未成熟期（4.81 d）,显著延长双尾新小绥螨后代雌成螨的寿命（45.43 d）,且对存活率、产卵前期、雌性比例和净增殖率无显著影响。三唑锡处理降低了双尾新小绥螨后代雌性比例（0.37）并显著降低了其后代净增殖率（15.91）,对未成熟期、产卵前期和雌雄成螨寿命均无显著影响。哒螨灵处理对双尾新小绥螨后代的未成熟期、存活率、雌成螨寿命、产卵前期、和雌性比例均未产生显著影响,仅显著延长了雌雄成螨寿命（51.22 d和44.23 d）。经所建Timing种群模型模拟,3种杀螨剂处理后双尾新小绥螨后代种群均可以继续增殖,经过60 d无限制增殖后,联苯肼脂处理的双尾新小绥螨后代种群数量是对照的1.62倍,达4 976头;哒螨灵处理（2 101头）和三唑锡处理（983头）的种群数量较对照分别减少了31.43%和67.92%。表明联苯肼脂对双尾新小绥螨后代影响较小,是较为安全的杀螨剂。