小麦品种C591的抗条锈性遗传分析

C591是原产于印度的普通小麦品种,苗期和成株期均对中国小麦生产上流行的条锈菌(Puccinia striiformis f.sp.tritici)主要生理小种表现良好抗性。本文以感病品种Taichung29作母本、C591作父本通过杂交制备了F₁代、F₂代和BC₁代种子,用人工接种方法研究了C591及其杂交后代对小麦条锈菌不同生理小种的苗期抗性并进行了遗传分析。结果显示,C591与Taichung29杂交F₁代植株对小麦条锈菌条中19号、条中29号和条中32号小种均表现出与C591相似的高抗,说明C591中的抗条锈基因主要为显性表达。根据杂交F₂代、BC₁代植株的抗性分离情况和F1代植株及亲本的抗性表现,说明C591中至少具有3对抗条锈基因,针对条锈菌不同的生理小种其有效性是不同的。对条中32号小种的抗性受1对显性基因控制,对条中29号小种的抗性受1对显性基因和2对隐性基因的独立控制,对条中19号小种的抗性受2对显性基因独立控制。结果表明,C591作为抗源在我国小麦抗锈育种中具有较大应用价值。     

小麦条锈菌对三唑酮敏感性生测体系优化及其抗药性分子标记开发

条锈病是小麦上重要的真菌病害，严重威胁小麦的生产安全，施用杀菌剂是防治小麦条锈病的重要措施。三唑酮是防治条锈病的主要药剂，但长期单一、大规模使用三唑酮势必导致病原菌抗药性出现，由于小麦条锈菌是严格的专性寄生菌，目前测定条锈菌对杀菌剂的敏感性实验主要在活体小麦上进行，实验结果易受外界环境影响。本研究通过培养皿内离体小麦叶段培养，采取定量接种和软件读数的方法，对2021年西北核心越夏区60个小麦条锈菌菌株进行三唑酮敏感性测定，生测结果表明供试菌株平均EC₅₀值为0.543μg·mL^-1,抗性菌株7株，敏感菌株53株，11.67%的供试菌株对三唑酮具有低至中等水平抗性，分子标记结果与生测结果高度吻合。本研究通过优化三唑酮对条锈病防治效果的室内生测体系，使得结果更加稳定、重复性好，同时基于敏感/抗药菌株靶标基因序列分析开发了高通量的抗药性竞争性等位基因特异性PCR-单核苷酸多态性分子标记(KASP-SNP),旨在为防治小麦条锈病筛选高效杀菌剂，同时开展田间小麦条锈菌抗药性监测，了解抗药性分布及抗性水平，为小麦条锈菌抗药性综合治理提供科学依据。     

西藏小麦条锈菌群体结构与遗传多样性

为查明西藏小麦条锈菌Puccinia striiformis f. sp. tritici群体结构和遗传多样性,采用中国鉴别寄主和近等基因系鉴别寄主,以及竞争性等位基因特异性PCR-单核苷酸多态性（kompetitive al-lele specific PCR-single nucleotide polymorphism,KASP-SNP）分子标记对2017年采自西藏的150个小麦条锈菌菌系分别进行表型分析和基因型分析。表型分析结果显示,中国鉴别寄主将150个菌系区分为 12 个已知小种、6 个已知致病类型和 13 个未知致病类型,所有菌系均不能侵染中四和Triticum spelta album鉴别寄主。近等基因系鉴别寄主将150个菌系区分为88个毒性类型,这些毒性类型均不侵染携带抗性基因Yr5、Yr10或Yr15的品种。基因型分析结果显示,26对引物将150个菌系划分为73个基因型,表明西藏小麦条锈菌群体基因型丰富。基因流分析结果表明,波密县与洛扎县小麦条锈菌亚群体之间的基因流N_m最高,达5.86,米林县西部与波密县、洛扎县、巴宜县、米林县东部条锈菌亚群体之间的N_m较低,分别为0.25、0.34、0.42和0.67,表明西藏不同地区条锈菌群体之间基因交流强度差异较大。说明西藏作为我国小麦条锈病的独立流行区,条锈菌群体毒性结构复杂,遗传多样性高。     

小麦抗源武汉2号和品冬34的抗条锈性遗传分析

为明确小麦品种武汉2号和品冬34对小麦条锈菌流行小种的抗病性及抗病遗传规律,用小麦条锈菌生理小种CYR29、CYR31、CYR32、CYR33以及致病类型Su11-4、Su11-5、Su11-11、PST-Ch42在苗期接种小麦品种武汉2号和品冬34进行抗病性鉴定,并用武汉2号和品冬34分别与感病亲本铭贤169进行杂交,对F₂群体和F_2：3家系在温室进行苗期遗传分析。结果表明：武汉2号对CYR29和CYR32表现感病,对其它小种和致病型均表现抗病,且对CYR31的抗性由1对隐性基因控制;品冬34对所测试的小种和致病类型均表现高抗,且对CYR32的抗性由1对显性基因控制。     

麦二叉蚜在10个小麦品种(系)室内苗期生物学反应及抗性分析

为了评价不同小麦品种(系)对麦二叉蚜的抗性,应用每株麦苗上接1头蚜虫的方法,在温室内用5个指标(发育历期D_D、成虫与幼虫的体重差W_D、成虫在与发育历期相等时间内的产子数F、相对日均体重增长量MRGR和成虫在与发育历期相等时间内的日均产仔数R_m)测定了10个小麦品种对麦二叉蚜的抗性,并以此为基础用多元方差分析法、多目标综合判别法和聚类分析法评价了这10个小麦品种(系)对麦二叉蚜的抗性,结果表明,Amigo最不适于麦二叉蚜在其上取食,抗性最好,Batis抗性较好,其他品种抗性较弱。     

禾谷镰刀菌CYP51A基因对五种三唑类杀菌剂敏感性的影响

为进一步明确14α-脱甲基酶编码基因CYP51A在禾谷镰刀菌Fusarium graminearum对三唑类杀菌剂敏感性中的作用,利用Split-marker方法敲除禾谷镰刀菌CYP51A基因并获得敲除CYP51A基因的禾谷镰刀菌ΔFgCYP51A菌株,比较该菌株和野生型菌株PH-1对5种三唑类杀菌剂的敏感性变化。结果表明,ΔFgCYP51A菌株对丙环唑、戊唑醇、烯唑醇、三唑醇和三唑酮的EC₅₀分别为0.024、0.047、0.148、0.154和0.474 mg/L。ΔFgCYP51A菌株对戊唑醇、三唑醇、三唑酮和丙环唑的敏感性均显著增加,而对烯唑醇的敏感性无明显变化。表明FgCYP51A基因与禾谷镰刀菌对三唑类杀菌剂的敏感性有关。     

以Taichung29为背景的小麦抗条锈病近等基因系转育进展

自1988年起,系统开展了以Taichung29为背景的小麦抗条锈病近等基因系转育及其基础性研究。采用回交法和系谱法相结合的转育方法,以春性品种Taichung29为轮回亲本作母本,分别与25个抗性供体即中国小麦条锈病菌鉴别寄主和国际上重要的抗条锈基因载体品种杂交、回交和自交。通过基因推导分析、单体分析和SSR标记技术检测目的基因,选育抗条锈近等基因系,现已获得重要进展,成功选育出8个以Taichung29为背景的抗条锈病单基因近等基因系,即Taichung29*6／Yr1、Taichung29*6／Yr2、Taichung29*6／Yr5、Taichung29*6／Yr7、Taichung29*6/Yr9、Taichung29*6／Yr10、Taichung29*6/YrSpP、Taichung29*6/YrKy2。另有9个组合转育获得343个抗性稳定株系,正检测其目的基因,3个组合转至BC₆F₃,自交纯合筛选抗性稳定株系,5个组合转至BC₅,继续回交转育。     

河南省小麦赤霉病菌对咯菌腈的敏感性

为明确河南省小麦赤霉病菌Fusarium graminearum对咯菌腈的敏感性,采用菌丝生长速率法测定了咯菌腈对从该省11个地市分离的95株菌株的毒力,通过方差分析法及聚类分析法对测定结果进行了分析,并研究了咯菌腈与多菌灵、戊唑醇对病菌毒力的相关性。结果显示：咯菌腈对小麦赤霉病菌菌丝生长的最低抑制浓度为0.1 μg/mL;咯菌腈对供试95株菌株的EC₅₀范围在0.003~0.088 μg/mL之间,平均EC₅₀为0.011 μg/mL;敏感性频率分布图显示,病菌群体中存在着对咯菌腈敏感性较低的亚群体,但67.4%供试菌株敏感性频率呈正态分布,将此部分菌株的EC₅₀平均值0.007 μg/mL作为小麦赤霉病菌对咯菌腈的敏感性基线。方差分析及聚类结果均显示,同一县市内的菌株对咯菌腈EC₅₀的最大值和最小值之比为1.1~8.3;除周口市沈丘县的菌株外,其余县市的菌株对咯菌腈敏感性差异不明显,咯菌腈EC₅₀平均值变化范围在0.005~0.028 g/mL之间,最大值是最小值的5.6倍;小麦赤霉病菌对咯菌腈的敏感性与其对多菌灵、戊唑醇的敏感性之间无明显相关性。表明河南省小麦赤霉病菌群体中尽管存在着敏感性较低的亚群体,但可通过药剂复配进行防控。     

2008年我国主要麦区白粉菌群体对三唑酮和喹氧灵的敏感性监测

采用拌种离体叶段法对我国6个省(市)分离的小麦白粉菌108个和104个单孢堆菌株分别对三唑酮和喹氧灵的敏感性进行了测定,并对两者之间的交互抗性进行分析。结果表明,供试菌株对三唑酮的平均EC50为94.34mg/L,平均抗性水平达45.14倍,有97.25%菌株产生了抗性,其中高抗菌株(抗性水平40)占35.19%,中抗菌株占55.56%。河北菌株的抗性水平明显高于其他五省。小麦白粉病菌群体对喹氧灵的敏感基线为0.0059mg/L,且与三唑酮无交互抗性。此研究信息可为小麦白粉病抗药性持续治理措施的制定以及杀菌剂生产和使用策略提供依据。     

紫外线诱导小麦条锈菌毒性突变的研究

 以紫外线照射小麦条锈菌条中29号小种夏孢子诱发突变,用抗病小麦品种筛选毒性突变体,建立了7个毒性突变菌株,毒性突变率为10^-6~10^-4,各突变菌株都能正常感染其筛选品种,其毒性谱不同于任何已知小种。抗源品种群体对突变菌株有明显的抗性分化。研究证实毒性突变是该菌毒性变异的重要途径。     

Hymenopteran Parasitoids on Fruit-infesting Tephritidae (Diptera) in Latin America and the Southern United States: Diversity, Distribution, Taxonomic Status and their use in Fruit Fly Biological Control

We first discuss the diversity of fruit fly (Diptera: Tephritidae) parasitoids (Hymenoptera) of the Neotropics. Even though the emphasis is on Anastrepha parasitoids, we also review all the information available on parasitoids attacking flies in the genera Ceratitis, Rhagoletis, Rhagoletotrypeta, Toxotrypana and Zonosemata. We center our analysis in parasitoid guilds, parasitoid assemblage size and fly host profiles. We also discuss distribution patterns and the taxonomic status of all known Anastrepha parasitoids. We follow by providing a historical overview of biological control of pestiferous tephritids in Latin American and Florida (U.S.A.) and by analyzing the success or failure of classical and augmentative biological control programs implemented to date in these regions. We also discuss the lack of success of introductions of exotic fruit fly parasitoids in various Latin American countries. We finish by discussing the most pressing needs related to fruit fly biological control (classical, augmentative, and conservation modalities) in areas of the Neotropics where fruit fly populations severely restrict the development of commercial fruit growing. We also address the need for much more intensive research on the bioecology of native fruit fly parasitoids.     

Brief Guide for Authors

正Journal of Arid Land(JAL)is an international journal(ISSN 1674-6767;CN 65-1278/K)for the natural sciences,sponsored by the Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences and Science Press.It is published by Science Press and Springer-Verlag Berlin Heidelberg bimonthly.JAL publishes original,innovative,and integrative research from arid and semiarid regions,ad     

The parasitoid complex ofLiriomyza cicerina on chickpea (Cicer arietinum)

Liriomyza cicerina (Diptera: Agromyzidae) is an important pest on chickpea in Turkey. The objective of this study was to determine the parasitoids and rates of parasitism ofL. cicerina on chickpea (Cicer arietinum L.) during the 2005 and 2006 seasons in ?anl?urfa province, Turkey. Leaves with mines were sampled weekly and kept in the laboratory to observe and count emerging leafminer and parasitoid adults. Eight parasitoid species were collected: the braconidsOpius monilicornis Fischer andOpius tersus Foerster and the eulophidsDiaulinopsis arenaria (Erdös) andNeochrysocharis formosa (Westwood), which occurred in both the winter and summer seasons;Diglyphus crassinervis Erdös,Neochrysocharis ambitiosa Hansson,Neochrysocharis sericea (Erdös) andPediobius metallicus (Nees), which occurred only in the summer growing areas.Diaulinopsis arenaria was the predominant parasitoid with 4–7.7% parasitism rate whileN. ambitiosa andO. monilicornis were the second and third most predominant species. The results of these trials show that sinceDia. arenaria occurred throughout every season, it could potentially be used for control of the leafminerL. cicerina.     

Plant–herbivore asynchrony necessitates augmentative releases of the exotic beetle,Zygogramma bicolorata,to enhance the biological control of P arthenium hysterophorus

Systematic information on the quantitative impact of Z ygogramma bicolorata on the biology of P arthenium hysterophorus is crucial as the seeds of this weed continue to germinate from the accumulated soil seed bank throughout the year in the form of different germinating flushes, while the activity of the beetle ceases during winter as it enters diapause. Therefore, plant–herbivore interactions need to be explored to develop predictions of the overall impact of the introduced beetle on the weed. The findings revealed that defoliation by Z . bicolorata had a significant impact on the plant height, density and flower production in flushes F ₃, F ₄ and F ₅, but not in F ₁ and F ₂ that exhibited longer periodicity, profuse branching, a longer flowering period and maximum flower production and contributed mostly to the existing seed soil bank. Therefore, total depletion of the existing soil seed bank was not possible. Consequently, the effect of augmentative field releases of laboratory‐reared beetles was explored on F ₁ and F ₂ in February for three consecutive years (2011–2013). Before initiating the trial, random soil samples were taken from the plots that were assigned to the paired treatments (i.e. with the beetle and without the beetle [insecticide‐treated]) and it was found that the seed bank in those samples did not differ. The single release of Z . bicolorata adults at five per plant at the six‐leaf stage significantly reduced the soil seed bank, compared to without the biocontrol agent, irrespective of the flushes at the end of the season.     

Effects of the saprophytic leaf mycoflora on growth and productivity of winter wheat

The effects of the saprophytic mycoflora and its interference with cereal aphids on growth and yield of winter and spring wheat was studied in field experiments in 1980, 1981 and 1982.Yields varied between 5000 and 8000 kg dry matter of kernels per ha. The effect of the saprophytic mycoflora on yield was determined in different treatments: A) no control measures against cereal aphids and saprophytic and necrotrophic fungi, B) no control of cereal aphids, control of saprophytic and necrotrophic fungi, C) control of cereal aphids and control of saprophytic and necrotrophic fungi, D) control of cereal aphids and stimulation of saprophytic mycoflora and E) control of cereal aphids, no control of saprophytic and necrotrophic fungi nor stimulation of saprophytic mycoflora.Considerable differences in top densities of saprophytic mycoflora (10 times as large in A and D as in B and C) were determined. The consequences of these differences for the growth and productivity of wheat were minor. A negative effect of saprophytic mycoflora on the yield could not be detected in 1981 and 1982, whereas a small positive significant effect was found in 1980. This stimulation may have been due to competition between necrotrophic fungal pathogens and saprophytic mycoflora. As a result of favourable weather conditions necrotrophic fungal pathogens were very numerous in 1980 and could form an important yield reducing factor. Yield levels may effect the importance of the necrotrophic and saprophytic mycoflora as yield reducing factors. Additionally, in the presence of aphid honeydew captafol was found to be relatively ineffective against saprophytic fungi.     

Relationship Between Production of the Phytotoxin Prehelminthosporol and Virulence in Isolates of the Plant Pathogenic Fungus Bipolaris sorokiniana

A gas chromatographic method was developed to quantify the phytotoxin prehelminthosporol, which is a sesquiterpene metabolite of the plant pathogen Bipolaris sorokiniana. The toxin was extracted from mycelium or culture filtrates, pre-cleaned using solid phase extraction, and analyzed by gas chromatography as a trimethylsilyl-derivative. The detection limit of the method was 5ngl^–1 (signal to noise ratio 4:1) which corresponds to ca. 15ng prehelminthosporol per mg dry weight of mycelium or 15ng prehelminthosporol per ml culture filtrate. The total amount of prehelminthosporol (mycelium plus culture filtrate) increased with cultivation time when examined in six isolates of B. sorokiniana after 6, 9, 12 and 15 days of incubation. The screening experiment of 17 isolates for prehelminthosporol production after 8 days of incubation revealed significant differences in the toxin production between the isolates. The isolates with low toxin production had lower virulence towards barley roots compared to those with higher production of the toxin. However, the virulence did not increase with prehelminthosporol level among the high producing isolates. Prehelminthosporol was also analyzed in a number of related Bipolaris and Drechslera species. In addition to B. sorokiniana, three out of six Bipolaris species (B. setariae, B. zeicola, B. victoriae) produced prehelminthosporol, which indicates that ability to produce prehelminthosporol is conserved among closely-related Bipolaris species.     

Effect of botanical insecticides and bacterial toxins on the gut enzyme of the rice leaffolderCnaphalocrocis medinalis

The effect of botanical insecticides and bacterial toxins on gut enzyme activity of larvae of the rice leaffolderCnaphalocrocis medinalis (Guenée) (Insecta: Lepidoptera: Pyralidae) was investigated. Gut enzyme activities were affected by botanical insecticides and bacterial toxin individually and in combination. When fed a diet of rice leaves treated with botanical insecticides and bacterial toxins, in bioassays the activities of gut tissue enzymes — acid phosphatases (ACP), alkaline phosphatases (ALP) and adenosine triphosphatases (ATPase) — of rice leaffolder larvae were affected. When combined, the effect was more severe at a low concentration. Larvae that were chronically exposed to botanical insecticides and bacterial toxins showed a reduction in weight (59–89%) and exhibited a significant reduction in ACP, ALP and ATPase activities. The combination ofBacillus thuringiensis kurstaki and botanical insecticides caused a decrease of twofold in enzyme activity even at reduced concentration. A synergistic effect was found when botanical insecticides and bacterial toxins were combined at low doses. These effects were most pronounced in early instars. Clear dose-response relationships were established with respect to enzyme activity. In conclusion: (i) biopesticides are relatively safe and biodegradable; (ii) a synergistic effect of botanical insecticides and bacterial toxins was found; (iii) less expensive, readily available and naturally occurring biopesticides could be an alternative for organic and inorganic pesticides in controlling RLF. http://www.phytoparasitica.org posting Sept. 28, 2004.