Reduced fungicide inputs to controlPhytophthora infestans in potato cultivars with high levels of polygenic resistance

Summary Final disease ratings, apparent infection rates and areas under disease progress curves were used to calculate lower fungicide rates for potato cultivars with high levels of polygenic resistance toPhytophthora infestans. Areas under disease progress curves offered more reliable indications than final disease ratings or apparent infection rates. Control of epidemic development was achieved using 20–80% of the recommended application rates of mancozeb on plots of cvs Brodick. Cara and Torridon compared with full application rates on cv. Maris Piper.     

Cereal leaf beetle (Oulema melanopus (L.)) population densities and winter wheat yields

Grain yields of a soft white winter wheat cultivar, cv. Ionia, susceptible to cereal leaf beetle (Oulema melanopus (L.)), were determined when the crop was subjected to four controlled infestation levels of the beetle in caged plots over a 3-year period in Michigan. Although identical infestation procedures and insect numbers were used each year, the intensity of larval infestation and feeding damage varied with the year. Significant (P < 0·01) grain losses occurred in plots that had at least 9·0 larvae per stem. The greatest yield loss was 45% and occurred with 15 larvae per stem and 85% feeding damage. Beetle damage had a greater effect on kernel weight than on the other yield components. Although economic thresholds should be conservative to allow for environmental variations, it appears that soft white winter wheat can often withstand beetle infestation levels greater than the current economic threshold of three or more eggs and largae per stem before the boot stage or one or more large larvae per flag leaf during heading.     

不同土壤肥力条件下麦秆还田与氮肥运筹对杂交稻氮素利用、产量及米质的影响

以杂交稻F优498为材料,研究了高、低土壤肥力下麦秆覆盖与氮肥运筹对杂交稻主要生育期氮素吸收利用特征、产量及米质的影响,并探讨了不同土壤肥力下麦秆覆盖和氮肥运筹对结实期剑叶SPAD值与稻米品质的形成的影响。结果表明,不同土壤肥力下,麦秆覆盖均有效促进杂交稻各生育时期氮素积累,提高了氮素利用效率以及稻谷产量,增加了稻米蛋白质含量、稻米胶稠度,显著降低了稻米垩白度以及垩白粒率,且高土壤肥力下麦秆覆盖优于低土壤肥力下麦秆覆盖处理。同时,不同土壤肥力下麦秆覆盖处理,均以m基肥∶m蘖肥∶m穗肥为3∶3∶4的氮肥运筹模式最优,均能有效调节水稻灌浆结实期叶片SPAD值,提高水稻氮素吸收利用效率及稻谷产量;但稻米品质方面,高土壤肥力以m基肥∶m蘖肥∶m穗肥为5∶3∶2时最佳;而低土壤肥力可适当提高氮肥后移比例,以m基肥∶m蘖肥∶m穗肥=3∶3∶4最佳。相关分析表明,水稻灌浆期剑叶SPAD值与稻米出糙率、整精米率以及蛋白质含量显著或极显著正相关(r=0.47*~0.90**);与垩百度、垩白粒率负相关,但相关未达显著水平;而高土壤肥力下稻米品质各项指标分别与齐穗后19~27d剑叶SPAD值,低土壤肥力下麦秆覆盖与齐穗后13~19d剑叶SPAD值相关系数最大。     

小麦新抗源Centrum抗条锈性特征及遗传分析

为了明确小麦种质Centrum的抗条锈性特征及抗性遗传规律,分别在杨凌和天水两地对其进行成株期抗条锈性评价,并以CYR29、CYR31、CYR32、CYR33、Su11-4、Su11-5、Su11-7、CH42等8个条锈菌生理小种对其进行苗期抗谱分析,以CYR29和CYR32对Centrum与感病亲本Avocet S构建的BC1、F2和F3群体进行苗期抗条锈病遗传分析。结果表明,Centrum在杨凌混合小种圃和天水自然诱发圃成株期均为免疫反应,苗期对所有参试小种均表现为免疫或近免疫;抗病遗传分析表明Centrum对CYR29和CYR32的抗性分别由同一对显性基因控制。     

Effects of cultivar resistance and single fungicide application on rice sheath blight, yield, and quality

The increased number of sheath blight (Rhizoctonia solani)-resistant rice (Oryza sativa) cultivars available will allow producers to use less fungicide and avoid significant reductions in grain and milling yields. Among cultivars currently in cultivation in the southern United States, sheath blight resistance levels range from very susceptible to moderately resistant. A study was conducted to determine the response of cultivars, with different levels of susceptibility, to sheath blight inoculations and fungicide application and to determine the impact of sheath blight disease development on rice yield and quality. Sheath blight epidemics in field plots were initiated by inoculation at the panicle differentiation growth stage in 2006 and 2007. Azoxystrobin at 0.17 kg a.i. ha⁻¹ was applied at mid-boot. Inoculation significantly increased sheath blight severity and incidence and caused yield losses of 8% in moderately resistant cv. Jupiter to 40% in very susceptible cv. Trenasse. Milling yields were affected to a lesser extent. Fungicide treatments reduced sheath blight incidence and severity, regardless of cultivar except in Jupiter. Single azoxystrobin applications were effective in minimizing yield loss due to sheath blight in all cultivars.     

不同阶段夜间增温对小麦生长特性及产量的影响

全球变暖表现出夜间增温幅度大于白天的非对称性增温特性,为明确不同阶段夜间增温对小麦生长发育特征及产量的影响,以扬麦18为试验材料,采用被动式增温装置分别对小麦分蘖期至拔节期(NWT-J)、拔节期至孕穗期(NWJ-B)、孕穗期至开花期(NWB-A)三个不同阶段进行夜间增温处理,以不增温为对照(NN),研究不同阶段夜间增温...     

Effect of foliar treatments to durum wheat on flag leaf senescence, grain yield, quality and deoxynivalenol contamination in North Italy

Since the production of durum wheat in the drier areas of the Mediterranean Basin is characterized by high variability in terms of yield and grain quality, there is also considerable interest in developing durum wheat in the northern regions, where the pedo-climatic conditions can offer the possibility of obtaining grain yields with higher technological quality and stability. However, the climatic conditions in the northern regions make durum wheat more prone to fungal foliar disease, particularly to Septoria Tritici Blotch (Septoria tritici Rob.) and to Fusarium Head Blight (Fusarium graminearum Petch and Fusarium culmorum Sacc.), with the consequent occurrence of DON in grains.Field experiments have been conducted over two growing seasons at four sites in North West Italy to evaluate the effect of fungicides and foliar nitrogen fertilizer application on durum wheat yield and grain quality. Five combinations of foliar application were compared at each site and each year (untreated control, azole fungicide application at heading, strobilurin fungicide at the stem elongation stage and/or at heading, the addition of a foliar N fertilizer to a fungicide programme). The following parameters were analysed: Septoria Tritici Blotch (STB) severity, flag leaf greenness using a chlorophyll meter, grain yield, test weight, grain protein content, ash content, vitreousness, Fusarium Head Blight (FHB) incidence and severity and deoxynivalenol (DON) contamination. The collected data underline that the cultivation of durum wheat at the climatic conditions of North Italy is actually risky and needs a direct control of fungal disease, which would be able to reduce the development of both foliar and head attacks. The double treatment, with a strobilurin application during the stem elongation stage and azole at heading, results to be an essential practice and showed advantages in terms of the delay of flag leaf senescence (+27%), STB control (+31), FHB control (+11%), yield (+32%) and DON contamination (−45%), compared to the untreated control. Other foliar treatments at heading, such as strobilurin or foliar N fertilizer applications, do not seem to provide any further advantage, for either grain yield or quality. No significant effect of fungicide or foliar N fertilizer application was recorded on the protein or ash concentration or vitreousness.     

陇南、陇东和关中地区小麦条锈病远程预警系统

为有效预测预报小麦条锈病,采用跨平台动态网页语言JAVA和数据库管理系统MySQL,以近30年积累资料构建的模型为基础,结合专家经验,建立了陇东、陇南和关中地区小麦条锈病远程预警系统(http://wrs.nwsuaf.edu.cn)。本系统由条锈病预测、信息管理、用户登录和后台管理4个模块组成,可以实现小麦条锈病流行程度的长、中、短期预测,以及病害造成的损失预测和病害防治的关键时期预测。利用平凉、天水和宝鸡2000-2013年间的相关资料对该系统进行了检验,其长、中、短期预测准确率分别为85.7%、92.6%和92.6%,可实现小麦条锈病准确远程预测和数据管理。     

小麦贵协3号成株期抗条锈病基因的遗传定位

贵协3号对当前的条锈病流行小种表现为近免疫或高抗。为更好地利用贵协3号,拓宽小麦抗性育种资源,以Avocet S(来自澳大利亚的高感条锈病小麦品种)为母本、贵协3号为父本构建的F_2:7代重组自交系(RIL)群体为材料,运用集群分离分析法(BSA)并结合转录组测序(BSR-Seq)和小麦55K SNP芯片技术对抗条锈病QTL进行遗传定位。结果表明,共检测到有7个抗条锈病QTL,分别位于小麦1B(1)、2A(2)、2D(1)、5A(2)和6B(1)染色体上。其中位于2AS染色体上的 Qyr.gaas.2A在三个环境中均被检测到,置信区间为AX-108824773～AX-111675237(0～2.5 cM),对应的物理区间为15.87～31.89 Mb(16.02 Mb),可解释17.07%～34.59%的表型变异。为了进一步提高该QTL的定位精度,在2AS染色体目标区段内设计了103对SSR标记引物,并选择2AS染色体上已报道的22个SSR标记,在双亲、抗感池和RIL群体中进行筛选和验证。最终筛选出6个多态性标记(Xcfd36、Xwmc382、hls-2A-04、h...     

小麦品种里勃留拉和咸农4号持久抗条锈性特点分析

通过测定甘肃陇南持久抗条锈性小麦品种里勃留拉、咸农4号对小麦条锈病流行小种条中32号苗期、成株期的抗性,探讨和分析了它们持久抗条锈性的特点。结果表明,里勃留拉、咸农4号在苗期和成株期对条中32号均表现感病,在苗期抗性组分潜伏期、孢子堆密度、产孢强度、产孢期等指标上,里勃留拉与咸农4号和高感对照品种辉县红明显不同,咸农4号与辉县红基本相当。在成株期病害田间流行速率、病情指数、千粒重损失率等指标上,里勃留拉显著低于咸农4号和辉县红,咸农4号亦明显低于辉县红。里勃留拉和咸农4号的持久抗条锈性机理有所不同。     

氮肥施用对旱地秸秆覆盖冬小麦旗叶生理特性的影响

为给旱地保护性耕作小麦水肥高效利用提供理论依据和建立合理的氮素管理模式,在渭北旱塬研究了秸秆覆盖下氮肥用量及施用时间对小麦旗叶光合特性及衰老的影响。结果表明,施氮量没有显著影响小麦花后旗叶的叶绿素相对含量(SPAD值)、光合速率和蒸腾速率,高氮用量明显增加小麦旗叶中丙二醛的累积,加速了旗叶衰老。氮素分次施用有延缓小麦旗叶SPAD值下降从而延缓旗叶衰老的作用,但是没有显著影响小麦旗叶的光合速率和蒸腾速率。秸秆覆盖较不覆盖显著提高了小麦旗叶的SPAD值、光合速率和蒸腾速率,并延缓了旗叶的衰老,进而提高了灌浆后期籽粒的灌浆速率,有增加千粒重的趋势。小麦籽粒产量变化范围为3 123~3 714kg·hm-2,试验年度氮素调控和秸秆覆盖均没有显著影响小麦的产量。     

返青期断根对秸秆覆盖冬小麦产量及叶片光合特性的影响

为了解返青期断根对黄土高原旱地保护性耕作下小麦产量形成及水分利用的调控作用,在陕西长武县开展旱地秸秆覆盖条件下冬小麦返青期断根试验,分析了返青期断根对冬小麦籽粒产量、地上部生物量、收获指数、产量构成三要素、拔节期群体数量、生育期耗水量、水分利用效率、花后旗叶光合特性及衰老特性的影响。结果表明,返青期断根对冬小麦地上部生物量、穗数、粒重和生育期耗水量没有显著影响。与CK(不断根)相比,返青期断根后冬小麦拔节期总茎数减少了11.9%,开花期叶面积指数、花后旗叶叶绿素含量、光合速率和蒸腾速率提高,分蘖成穗率、穗粒数、籽粒产量、收获指数和水分利用效率分别增加了14.1%、10.5%、8.2%、10.4%、17.5%和20.4%。这说明返青期断根可促进秸秆覆盖条件下冬小麦分蘖成穗,增加花后旗叶光合作用,改善穗部结实特性,提高籽粒产量和水分高效利用。     

湖北省小麦种质资源的分布及农艺性状和抗病性评价

为了解湖北省小麦种质资源特性并发掘可供育种利用的优良基因资源,对保存的874份湖北省小麦种质资源从地理分布、农艺性状、品质及抗病性方面进行了统计分析和综合评价。结果表明：（1）湖北省小麦种质主要分布在平原和丘陵地区,江汉平原麦区分布数量最多,而鄂西北山地麦区小麦资源最为富集,除东经112°74′至114°15′之间、北纬31°18′至32°09′之间和北纬29°37′以南地区分布较少外,其他地区分布较为均匀;（2）供试小麦种质以具有长芒、白壳、红粒、弱冬性和中熟等性状为主,4个产量性状（株高、穗长、千粒重和穗粒数）和4个品质性状（硬度、沉淀值、粗蛋白和赖氨酸含量）的变异幅度大,多样性指数高;（3）抗病性以对根腐病、黄矮病和条锈病抗性最强,而对赤霉、叶锈、秆锈及白粉病的抗性较差;（4）各性状多样性指数从大到小依次为：千粒重＞粗蛋白含量＝赖氨酸含量＞株高＞穗粒数＞沉淀值＞穗长＞硬度＞条锈病抗性＝黄矮病抗性＞根腐叶病抗性＞成熟期＞赤霉病抗性＞根腐穗病抗性＞冬春性＞芒＞壳色＞白粉病抗性＞粒色＞叶锈病抗性＞秆锈病抗性。     

早稻直播覆膜旱作对灌浆成熟期根叶生理特性及产量的影响

 对早稻直播覆膜旱作与常规水作栽培对灌浆成熟期根叶生理特性及产量的影响进行了比较研究。与常规水作栽培水稻相比，直播覆膜旱作早稻千粒重显著下降，是导致产量明显下降的主要原因之一。而粒重的下降则主要归因于直播覆膜旱作较常规水作水稻灌浆成熟期根叶生理机能的衰退要快，表现为根系活力、叶片叶绿素含量、叶面积指数、净光合速率等下降较快，叶片超氧化物歧化酶、过氧化物酶等保护酶活性迅速下降，而丙二醛含量较高，使籽粒干物质积累受阻，揭示出提高灌浆成熟期根叶生理机能是进一步提高直播覆膜旱作早稻粒重和最终产量的重要途径。     

烯效唑对水稻氮代谢及稻米蛋白质含量的影响

以杂交稻组合汕优63为材料,探讨了烯效唑处理对水稻开花后剑叶和籽粒氮代谢、稻米蛋白质含量及产量的影响。结果表明,烯效唑处理后,籽粒灌浆前、中期剑叶内可溶性蛋白质含量提高,而成熟期其含量与对照基本相同,甚至略低于对照;烯效唑提高了强、弱势粒中谷氨酰胺合成酶活性以及强势粒发育前期的非蛋白氮含量,并促进其向蛋白氮的转化,使成熟期非蛋白氮含量低于对照,而各时期蛋白氮含量均高于对照,成熟期强、弱势粒中蛋白氮含量和单粒蛋白氮绝对积累量均得以提高;烯效唑提高了稻米内蛋白质含量和蛋白质产量,浸种和喷施处理蛋白质含量平均分别比对照高7.2%和8.3%,蛋白质产量平均分别比对照高13.1%和13.4%。     

不同落黄类型小麦品种的籽粒灌浆及叶片光合特性

为给不同落黄类型小麦品种的选育提供理论依据,研究了不同落黄类型小麦品种籽粒灌浆和穗、茎、叶对籽粒灌浆的贡献。结果表明,早衰落黄型、灰白落黄型、全身落黄型小麦品种籽粒灌浆特性、叶片叶绿素含量变化和旗叶光合速率均存在较大差异。早衰落黄型和灰白落黄型品种旗叶和倒二叶叶绿素含量衰减发生早,下降速度快,旗叶光合速率低,籽粒物质积累在灌浆前中期多而后期较少;全身落黄型品种叶绿素含量衰减发生晚,下降速度缓慢,旗叶光合速率高,穗、茎、叶对籽粒灌浆的贡献率较大,籽粒平均灌浆速率高,籽粒饱满指数较高。因此认为,全身落黄型是小麦高产育种选择的重要指标。     

化学调控剂不同施用方式对小麦抗冻性的影响

小偃22是陕西省主栽小麦品种之一,具有一定的耐条锈病性。为了明确小偃22耐条锈病性的生理机制,为利用生理指标变化进行耐病性小麦品种的鉴定提供依据,以小麦条锈菌条中32号小种接种小偃22和对照品种铭贤169,用LI6400型光合系统仪分别对小麦发病旗叶的光合作用和蒸腾作用等生理指标的日变化进行监测。结果表明,受条锈菌侵染后,小偃22和铭贤169叶片光合作用和蒸腾作用与健叶相比均有所变化,表现为光合速率降低,细胞间隙CO2浓度、气孔导度、蒸腾速率等有所升高。小偃22病叶的水分代谢较健叶的变化幅度小于铭贤169,光合速率、蒸腾速率和水分利用效率的变化幅度与铭贤169差异明显,说明小偃22感病后能维持较高的光合速率、水分利用效率和较低的蒸腾速率,起到一定的生理补偿作用,以降低条锈菌侵染造成的危害,进而起到较好的抗病保产效果。     

小麦灌浆中期旗叶黄化速率与产量性状及部分品质性状的关系

为了给高产、优质小麦育种和栽培提供参考依据,以50个小麦基因型为试验材料,研究不同小麦基因型间灌浆中期旗叶黄化速率的差异及其与产量性状和部分品质指标的关系。结果表明：（1）不同小麦基因型间灌浆中期旗叶黄化速率差异极显著;（2）灌浆中期旗叶黄化速率与穗粒数、千粒重和穗粒重呈负相关,相关系数（R）分别为-0.171、-0.405^**和-0.369^**;（3）灌浆中期旗叶黄化速率与蛋白质含量、湿面筋含量和沉降值的相关系数（R）分别为-0.085、-0.111和-0.045,相关不显著。     

水氮交互对弱筋小麦蔗糖含量和籽粒淀粉积累及品质的影响

为了解弱筋小麦产量和品质的水氮调控效应,于2003~2004年度在大田条件下研究了水氮因素及其交互作用对弱筋小麦旗叶蔗糖合成、籽粒淀粉积累、产量和品质性状的影响。结果表明,就弱筋小麦品种豫麦50而言,150kg/hm2的氮肥用量有利于促进旗叶蔗糖合成,增加籽粒淀粉积累量和籽粒产量,而氮肥施用量过多(270kg/hm2)或全生育期不施氮肥均不利于弱筋小麦产量和品质的形成;在试验条件下,灌拔节水 灌浆水(花后15d)有利于后期旗叶蔗糖合成和籽粒淀粉积累,其籽粒产量最高,品质性状最优;而灌拔节水(1水)或拔节水 灌浆水 麦黄水(3水)均不利于旗叶蔗糖合成和籽粒淀粉积累,导致籽粒产量和品质不同程度的下降。从水、氮的交互效应看,以全生育期施氮量150kg/hm2并保证拔节水和灌浆水是弱筋小麦较为理想的水氮运筹方式。     

栽培模式和花后去叶对小麦产量及其构成的影响

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,研究了不同栽培模式下花后去叶对产量及其构成的影响。结果表明,不同栽培模式对穗粒数、千粒重和籽粒产量的影响差异显著（P〈0．05）,集雨面栽培下穗粒数最多;全程覆膜、覆膜150d和集雨面栽培模式千粒重显著高于常规栽培和三密一稀栽培;全程覆膜栽培下籽粒产量最高。去叶处理对稳粒数、千粒重和籽粒产量影响差异显著（P〈O．05）,各去叶处理穗粒数均大于对照。不同去叶处理千粒重均小于不去叶对照。不同去叶处理籽粒产量大小顺序为去全旗叶〉对照〉只保留旗叶〉去1／2旗叶〉去旗叶、倒二叶。去叶处理对穗粒数、千粒重和籽粒产量的影响因栽培模式不同而有差异。