Analysis of a Long-term Experiment with Repeated-measurement Models

Long‐term experiments are a classical case of repeated measurements. Traits are measured on the same experimental unit over many years so that correlations arise between the observations made on the same plot in consecutive years. This paper describes the analysis of a three‐crop‐rotation long‐term experiment. We analysed the yields of the crops and the organic carbon content in the topsoil over 30 consecutive years. Several variance–covariance approaches are discussed and the trait‐specific best fit is interpreted. Mixed models are used to describe the structure of the experiment. Both yields and soil organic carbon show a more or less pronounced variance heterogeneity. Especially for yields, the heterogeneity of cycles and years is dominant. The consideration of correlations results in a better model fit in all cases.     

Factors affecting the development of disease symptoms in potatoes infected by <Emphasis Type="Italic">Tobacco rattle virus</Emphasis>

Infection of potato plants with Tobacco rattle virus by its nematode vector can have different outcomes, including the development of spraing symptoms in progeny tubers. A novel syndrome described here comprises a generalized mottle in leaves on all stems, together with virtually total failure to produce daughter tubers. The outcome of infection depends partly on the potato genotype, but field trials with 15 varieties showed that the incidence and severity of spraing symptoms at three sites differed. There was no evidence that this was due to differences in virulence among the virus isolates at the sites, but it was probably the result of environmental differences that influenced the numbers and activity of the vector nematodes. At the most severely affected site, spraing symptoms were found in all varieties tested, except Record, including several that were not affected at the other two sites. Taking both severity and incidence of symptoms into account, the ranking of varieties was similar at each site. The incidence of spraing symptoms was greater in larger than in smaller tubers, and increased with later harvest dates, but did not increase when early harvested tubers were stored. Tobacco rattle viruswas detected in the roots of many of the weeds growing at one of the sites and in the roots of a few plants of the subsequent barley crop.     

猪伪狂犬病基因缺失疫苗的制备、安全性、免疫原性、保存期测定及区域试验

为了提供有效的伪狂犬病疫苗，用鸡胚成纤维细胞扩大培养了PrV HB-98突变株（TK^-/gG^-/LacZ^＋），研制了伪狂犬病基因缺失疫苗，并对该疫苗经肌肉接种、经口等免疫途径的最小免疫剂量进行了测定，同时也对4批疫苗的安全性、效力、免疫期和保存期进行了检测；同时将4批疫苗用于免疫23个猪场的母猪、新生仔猪和育肥猪进行区域试验。测定结果表明，疫苗经上述两种途径接种对不同阶段猪的最小免疫剂量均为10^5.0 TCID50；10倍免疫剂量的疫苗对初生仔猪、15日龄仔猪和妊娠母猪是安全的，免疫猪能抵抗强毒的攻击；疫苗在4℃和-20℃下分别可保存6个月和12个月。对伪狂犬病毒抗体阴性的70日龄商品猪和种猪的免疫期为6个月。田间试验表明，4批猪伪狂犬病基因缺失疫苗安全有效，并可用于仔猪发病时的紧急接种。为猪伪狂犬病基因工程疫苗的制备与应用提供了有力的依据。     

Nanostructured liquid crystalline particle assisted delivery of 2,4-dichlorophenoxyacetic acid to weeds,crops and model plants

Routine agricultural practices are heavily dependent on the use of surfactants, many of which are toxic to humans and detrimental to the environment. In proof of concept work we have previously shown the potential of nanostructured liquid crystalline particles (NLCP) to safely interact with plant leaf cuticular surfaces with minimal impact on epicuticular waxes. Here we demonstrate the use of NLCP to effectively deliver the auxin herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) to plant leaves in laboratory and field studies. In the laboratory, the physiological stress responses of lupin, Lupinus angustifolius (L.) (Fabaceae) towards NLCP spray applications were shown to be much reduced in comparison with application of two common surfactants. Phytotoxicity assays of 2,4-D loaded NLCP were used to validate the herbicidal effects on Arabidopsis thaliana (L.) Heynth. (Brassicaceae) and established a similarity with that of surfactant assisted 2,4-D delivery when tested at a concentration of 0.1%. Field trials were conducted to test the efficacy of NLCP-assisted delivery of 2,4-D in comparison with commercial surfactants for the control of the invasive weed wild radish, Raphanus raphanistrum (L.) (Brassicaceae), in wheat, Triticum aestivum (L.) (Poaceae) crop fields. Compared against Estercide 800, a commercially available 2,4-D formulation, NLCP assisted delivery of 2,4-D was effective at low concentrations of 0.03% and 0.06%. The crop yield remained similar for all the tested concentrations and formulations of 2,4-D loaded NLCP and Estercide 800. This is the first report to directly show that, as an alternative to conventional methods, NLCP can be used under both laboratory and field conditions to successfully delivery an agrochemical.     

The optimal nutrition of maize in the hungarian national long‐term field experimental network

In Hungary, maize is grown on 1 million ha and occupies more than 20% of the arable land. The rich assortment of maize cultivars of different vegetation periods and different responses to nutritional effects, water supply etc. gives the growers the possibility to choose the cultivars suiting best the site characteristics (Jolânkai et al. 1999). Among the cereals maize has the highest genetical potential. To utilize its yield and quality potential, soil types of high nutrient content and regular nutrient supply are required (Gyõrffy, 1979). Both over‐ and under‐fertilization have an unfavourable effect on the yield and quality of maize (Debreczeni, 1985). Crops can be supplied with the appropriate nutrient amounts only with the knowledge of soil characteristics in the different agro‐ecological regions (nutrient content, water supply, soil compactness, pH, nutrient supplying capacity etc.). In Hungary, a network of long‐term field fertilization trials with uniform fertilizer treatments has been maintained at nine experimental sites representing different agro‐ecological regions of the country. This experimental network gives a basis to test the nutrient responses of our main crops and calibrate their optimal nutrient supply (Kismányoky, 1991).     

两种底拖网渔业资源调查船捕捞效率标准化分析

渔业资源科学调查是开展渔业资源状况评价、物种保护和管理等分析的重要数据来源，当调查方式发生变化时，维持数据的时间一致性至关重要。因此，原位试验获取不同调查方式的捕捞效率校正因子（fishing power correction，FPC）成为资源状况评价的先决条件。本研究通过平行拖网对比试验分析了科学调查船“中渔科211”（试验船）和生产性渔船“浙嵊渔10201-10243”（标准船）在开展渔业资源调查时对不同种类或类群的渔获率差异。结果表明，标准船和试验船平均渔获率分别为（47.27~1836.72）kg/nmile²和（12.28~311.85）kg/nmile²。标准船主要种类为小黄鱼（），渔获率范围分别为（1.17~1113.26）kg/nmile²和（0~565.39）kg/nmile²；试验船主要种类为鳀（），渔获率范围分别为（0~277.59）kg/nmile²和（0~125.24）kg/nmile²。2种调查方式对不同种类/组的渔获率随深度变化趋势出现分化，其中总渔获率、鱼类、银鲳（Apogonichthys lineatus）、绿鳍鱼（）8个种类/组表现为相似的变化趋势；甲壳类、细点圆趾蟹（Erisphex pottii）5个种类/组变化趋势相反；头足类、小黄鱼、龙头鱼在各深度变化具有异质性特征。这种变化与网口垂直扩张和所在水层位置有关。均值比和Kappenman方法估计的总渔获率FPC分别为0.35（95%置信区间为0.24~0.61）和0.43（95%置信区间为0.27~0.70），各种类渔获率均值比结果显示，FPC变化范围在0.03~2.61，其中总渔获率、鱼类、头足类、小黄鱼和绿鳍鱼达到显著水平，建议对上述种类的资源丰度指标年际变化趋势分析时进行数据校正。标准船以近底层种类为调查对象，尤其在捕获经济种类方面表现出优良性能，但对完整生态系统代表性较弱。试验船适合浅水区调查，在深水区由于网口垂直扩张不足，且网位存在上浮现象，难以反映近底层生态系统。     

摩擦复充种型孔带式水稻精量排种器充种性能分析与验证

为解决杂交稻工厂化穴盘育秧低播量精密播种问题,提出了一种摩擦复充种型孔带式水稻精量排种器,对种子充填过程进行了力学和运动学分析,确定影响试验指标的影响因素分别为型孔方向角、型孔带速度、型孔带倾角和种层厚度。通过EDEM离散元软件仿真分析了种子多次循环重复充种过程和充种效果,并分别分析了型孔带速度、型孔带倾角、种层厚度对充种性能的影响规律。基于仿真分析结果进行了较优组合验证试验,结果表明:在型孔方向角为90°,型孔带倾角为43°,型孔带转速为0.11 m/s,种层厚度为50 mm时充种合格率为96.4%,多粒率为1.4%,漏充率为2.2%,种子破碎率为0.18%,效果较优。摩擦复充种型孔带式水稻精量排种器能够满足杂交稻低播量精密播种的农艺要求,研究结果为工厂化穴盘育秧精量播种机的设计提供参考。     

Genomewide association study reveals novel quantitative trait loci associated with resistance towards Septoria tritici blotch in North European winter wheat

Fungal diseases are a major constraint for wheat production. Effective disease resistance is essential for ensuring a high production quality and yield. One of the most severe fungal diseases of wheat is Septoria tritici blotch (STB), which influences wheat production across the world. In this study, genomewide association mapping was used to identify new chromosomal regions on the wheat genome conferring effective resistance towards STB. A winter wheat population of 164 North European varieties and breeding lines was genotyped with 15K single nucleotide polymorphism (SNP) wheat array. The varieties were evaluated for STB in field trials at three locations in Denmark and across 3 years. The association analysis revealed four quantitative trait loci, on chromosomes 1B, 2A, 5D and 7A, highly associated with STB resistance. By comparing varieties containing several quantitative trait loci (QTL) with varieties containing none of the found QTL, a significant difference was found in the mean disease score. This indicates that an effective resistance can be obtained by pyramiding several QTL.     

1．6％胺鲜酯对水稻生长影响及增产作用研究

[目的]研究1．6％胺鲜酯对水稻生长和增产作用。[方法]在田间小区试验条件下,研究试验药剂不同使用剂量对水稻生长、增产效果和田间应用安全性。[结果]1．6％胺鲜酯水剂制剂稀释1000—1500倍,连续用药2次,水稻增产率达6．51％以上,与对照药剂相当,对环境和作物安全。[结论]1．6％胺鲜酯水剂是调节水稻生长性状和增产增效较为理想的药剂。     

木醋液的杀线活性及对根结线虫病的防治效果研究

 【目的】初步探究木醋液对根结线虫2龄幼虫的抑制作用,以及木醋液及其配剂对根结线虫病的田间防治效果。【方法】采用浸渍法测定不同稀释浓度的木醋液对根结线虫2龄幼虫抑制作用,根据实验室测定结果设计小区试验,进行木醋液及其配剂对石榴根结线虫病、番茄根结线虫病的大田防治。【结果】不同稀释浓度的木醋液对4种常见根结线虫的2龄幼虫均有抑制作用,随着稀释倍数的增加,抑制作用减小。木醋液稀释浓度为150倍处理72 h时,北方根结线虫、花生根结线虫、南方根结线虫、爪哇根结线虫的校正死亡率分别达到了76.3%、78.４%、77.9%和72.2%。木醋液和木醋液配剂对石榴根结线虫病有较好的防治效果,防治效果分别达到了63.9%和50.5%。木醋液和木醋液配剂对番茄根结线虫病的防治效果,寻甸分别为54.1%和28.6%,个旧的为27.8%和19.6%。【结论】初步证明木醋液对根结线虫2龄幼虫有抑制作用,对石榴根结线虫病和番茄根结线虫病有防治效果,对防治根结线虫病有研究价值、应用价值和开发前景。