An extended interspecific gene pool available to peach and almond breeding as characterized using simple sequence repeat (SSR) markers

Genetic diversity, as revealed by eighteenSimple Sequence Repeat (SSR) markers inthirty almond [P. dulcis (Mill.) D.A.Webb], twenty fresh-market peach [Prunus persica (L.), Basch], fifteenprocessing clingstone peach cultivars, andten rootstocks, established the geneticrelatedness among cultivars andcharacterized the variation within andbetween species. One accession each of thewild Prunus species, P.davidiana [(Carriere) Franch] and P.webbii [(Spach.) Vieh.], was included inthe analysis. The number of presumedalleles revealed by the SSR analysis rangedfrom one to six in peach whereas almondcultivars showed a range of three to nine.Peach cultivars clustered into ten groups,which are in general agreement withdocumented origin. Most processingclingstone peach cultivars clusteredseparately from fresh-market freestonecultivars supporting a distinct origin. Twomajor clusters were observed in almond withone containing California cultivars and theother containing European cultivars and theimportant California cultivar Mission.Results establish the value of SSR markersfor distinguishing different geneticlineages and characterize an extensive andlargely unexploited inter-species gene poolavailable to peach and almond breedingprograms.     

农用地分等因素法与样地法比较——以重庆市九龙坡区为例

以重庆市九龙坡区为例,对农用地分等中的因素法和样地法及其结果进行了比较。结果表明:①虽然两种分等方法在分等原理、计算方法等方面不同,但是其分等结果在等别面积和空间一致性方面差异较小;②因素法分等较复杂,不利于技术人员理解和掌握;③样地法分等简便易行,易于掌握,但建立跨区域的因素指标体系方法还不成熟。     

适合我国东北寒冷地区栽培的桑树品种鉴定试验

为了选拔适合我国东北寒冷地区栽培的桑树品种,对北方地区保存、引进的15份桑树品种资源材料进行了大面积生产鉴定试验。综合各品种的抗寒性和产量性状成绩,选拔出龙桑一号、辽鲁11号、桲椤桑3个性状较为突出的品种。3个品种在年均气温2.6℃、年均降雨量350 mm左右的干旱寒冷地区栽培,枯梢率分别为12.4%、21.3%、18.0%,桑叶产量分别达到10500、8700、11280 kg/hm2,具有抗寒性强、产叶量高的特点,适合作为东北寒冷地区养蚕用桑和生态经济林建设栽植的桑树品种。     

Comparison of the VIDAS and IMMULITE‐2000 methods for cortisol measurement in canine serum

Background: Serum cortisol concentration is often measured in dogs for the diagnosis and monitoring of adrenal disease. An enzyme‐linked fluorescent assay (VIDAS method) on the MiniVidas analyzer has been validated for the measurement of cortisol concentration in human serum and could have applications for canine samples. Objective: The aim of this study was to compare canine cortisol results obtained using the VIDAS method with those obtained using the IMMULITE‐2000 immunoassay, which has previously been validated for canine serum. Methods: The concentration of cortisol in 40 canine serum samples was determined concurrently with the VIDAS and IMMULITE methods, the latter as the reference method. Pearson's correlation coefficient, linear, and Deming regression analyses and Bland–Altman analysis were used to compare the 2 methods. Acceptability of the new method was judged using a medical decision chart (MEDx chart). Results: Cortisol concentrations obtained with the IMMULITE method ranged from 23.1 to 1380 nmol/L. Correlation (r=.977) and simple linear regression (slope=1.0722, confidence interval [CI] 0.996–1.148; intercept=?4.799, CI ?42.838 to 33.240) revealed no proportional or constant error. Based on Deming regression and a Bland–Altman plot the 2 methods gave comparable results. The MEDx chart indicated that performance of the new method was good at decision limits of 40, 132, and 480 nmol/L. Conclusion: Results of the VIDAS method were comparable to those of the IMMULITE‐2000 reference method such that the VIDAS may be used as an alternative assay to evaluate serum cortisol concentration in dogs for the diagnosis of adrenal disease.     

Comparison of Soil Clean-up Standards for Trace Elements Between Countries: Why do they differ? (9 pages)

Goal, Scope and Background

In the nineteen nineties most European countries issued legislation on soil protection, including soil contamination. In the case of a presumed contamination, soil investigation mostly follows a stepwise approach starting with a preliminary investigation, then an in-depth investigation and, finally, remediation. Soil clean-up standards are often foreseen as trigger criteria to determine the need for an in-depth soil investigation or for remediation. There are however large differences in soil clean-up standards. This is partly because of the different roles of soil clean-up standards in each legislative framework and partly because of differences in the soil clean-up standard (SCS) derivation procedures. Despites these differences there are large similarities in the concepts of the derivation procedures for clean-up standards. A better understanding of the differences in clean-up standards is needed. In order to clarify the variation, the background of the clean-up standards for a selected number of countries was investigated. The objective of this paper is to investigate the underlying reason why country-wide generic soil and groundwater clean-up standards of eight trace elements (cadmium, chromium (III), copper, mercury, lead, nickel, zinc and arsenic) differ between the selected countries.

Main Features

To avoid misinterpretation of the differences in application of the clean-up standards, a short overview of the legislative role of clean-up standards is given first. Differences in model concepts and parameter values are discussed, followed by a comparison of the generic soil and groundwater clean-up standards for trace elements and a discussion on the sources of variation. The influence of the use of ecotoxicological criteria and data for the derivation of soil clean-up standards will be discussed in more detail. Selected countries were Canada, the Flemish Region (Belgium), France, Germany, Great-Britain, the Netherlands, Norway, Sweden, Switzerland and United States of America (USA).

Results and Discussion

When soil clean-up standards for eight trace elements (cadmium, chromium (III), copper, mercury, lead, nickel, zinc and arsenic) were compared between the selected countries differences of more than a factor 1000 arose. Notwithstanding the use of similar derivation procedures, differences were caused by the use of different software models with their specific input data, boundary conditions and applied protection criteria for humans and the ecology. Ecotoxicological criteria tend to lower the soil clean-up standard for the selected trace elements.

Conclusions

In the countries that are included in this study, clean-up standards are used is different ways, this is for the determination of the necessity for remediation or for the need for further soil investigation. This paper shows a wide variation in the clean-up standards, which has further implication on the decision for remediation or further investigation and, hence, the financial costs of soil management. All the clean-up standards have as primary goal the protection of human health. A number of countries also include the protection of the ecological function of the soil. Differences in selected software model, (standard) parameters values, selected human toxicological and ecotoxicological criteria, are reason for a substantial variation in the clean-up standards for trace elements.

Recommendations and Perspective

. Is this variation justified? The derivation of soil clean-up standards involves - besides scientific elements - political elements, like differentiation in landuse types (agricultural, residential, recreational, industrial), receptor at risk or protection level. It is obvious that harmonization of these elements will be complicated. However, a European action programme, like the thematic strategy for soil protection, could initiate this process of harmonization. Nevertheless, soil-clean-up standards could never be uniform over the whole of Europe because they include country specific elements (geographical, ethnological) and political decisions.     

农用土地经济定级中两种方法的比较研究——以新疆一四八农场为例

以新疆一四八农场为例，对农用土地经济定级中的模拟作物产量法和综合土地质量法及其结果进行了比较，结果表明：（1）两种方法定级程序基本一致，在地方性区域内的定级结果均较为准确，且一致性较大；（2）模拟作物产量法结果的区域可比性强，但方法复杂；（3）综合土 地质量法方法简便易行，但结果的区域可比性差；（4）两种方法结合，能有效地建立便于比较和纳入全国体系的农用土地经济等级指数。     

陕北"一户一田"和"一组一田"耕地细碎化整治模式与绩效评价

耕地细碎化是当前制约中国农业现代化发展的重要因素,如何解决耕地细碎化问题已经成为推动小农户和现代农业有机衔接的必然路径。该研究基于实地农户调研数据和半结构访谈内容,对陕北榆林市榆阳区首创的"一户一田"和"一组一田"2种耕地细碎化整治模式进行系统剖析,并采用双重差分(Difference-in-difference, DID)模型定量分析2种模式的绩效差异。研究发现:1)"一户一田"模式是农民自发的产权重组和分散流转,并与政府支持的土地整治项目叠加与综合;"一组一田"模式是一种"以家庭承包经营为基础、统分收放自如的双层经营体制"创新模式,也是产权改革、统分流转、土地整治与统分经营管理的有机结合。2)"一户一田"和"一组一田"两种模式均能有效解决耕地细碎化问题,显著增加耕地面积,实施后耕地面积增加率分别为6.02%和57.58%;同时也使得农业机械化水平有所提高,显著提升农业生产效率与作物产量,作物产量增加率分别为12.54%和19.87%,"一组一田"提升更为明显。3)2种模式均有利于提高农户收入,"一户一田"主要是通过增加农业种植收入来提高总收入;"一组一田"对农户收入提升更加显著,除增加农业收入外,也通过产业转型增加了务工收入。与"一户一田"模式相比,"一组一田"模式更能够促进集中连片、规模扩大、设施完善、经营现代化的高标准农田建设。为解决耕地细碎化问题,应加强政策引导和支持,挖掘村内能人价值,明晰合作社、分社和农民的责、权、利关系等,促进小农户和现代农业发展有机衔接。     

牛病毒性腹泻病毒检测方法研究进展

引起牛病毒性腹泻/黏膜病(bovine viral diarrhea—mucosal disease,BVD—MD)的病原为牛病毒性腹泻病毒(Bovine viral diarrhea virus,BVDV),牛感染后会出现与其他腹泻病相似的症状,仅通过临床表现和病理观察很难做出准确鉴别;其次持续感染(PI)牛是该病主要传染源,如何鉴别、净化牛场中PI牛十分重要。为了检测BVDV病原和净化PI牛,选择一种最佳的检测方法非常重要。文章对目前常用的不同BVDV检测方法进行了比较分析。不同检测方法在敏感性、特异性等方面均存在差异。实际应用时应根据检测目的综合考虑,选择适宜的检测方法。     

非洲猪瘟病毒核酸定性检测方法比对

为提升兽医实验室非洲猪瘟病毒核酸检测能力和质量控制水平,积累检测经验,以更好地开展非洲猪瘟检测,2020年7月,参加了北京市农业农村局组织的“非洲猪瘟实验室检测能力比对”项目。本次比对同时选用《非洲猪瘟检疫技术规范》(SNT 1559—2010标准)中的普通PCR方法、荧光定量PCR方法以及商品化试剂盒,对5份验证样品开展非洲猪瘟病毒核酸检测和结果比对。比对发现,3种检测方法结果一致,样品检测结果与预期一致,结果满意。此次比对确认了实验室现有检测方法能够满足非洲猪瘟病毒核酸的日常检测需求,同时提升了实验室人员的检测能力,积累了检测经验,可为非洲猪瘟防控提供有力的技术支撑。     

基于非洲猪瘟病毒标准物质的荧光PCR检测试剂盒初步评价

为探究非洲猪瘟病毒(African swine fever virus,ASFV)标准物质作为试剂盒评价体系的可行性,比较了市场上5种主流品牌ASFV荧光PCR检测试剂盒的检测性能。使用ASFV P72基因核酸标准物质作为模板,根据5种试剂盒说明书分别进行相应的荧光定量PCR检测,结合扩增曲线、Ct值,分析不同试剂盒的敏感性、可重复性以及所需反应时间。结果显示:5种试剂盒的阴性、阳性对照均成立,最低检测限均为5.9×10^-1拷贝/μL;4个厂家的试剂盒线性关系R2>0.98,其中最优的R²=0.994,离散度最小;各试剂盒的实际反应耗时与理论反应耗时均有一定差异(0.20~0.96 h)。结果表明,各生产厂家使用P72基因作为靶基因研制的ASFV荧光PCR检测试剂盒都可以使用ASFV标准物质作为评价体系,来评判试剂盒的检测性能。本试验为各实验室不同样品检测的ASFV荧光PCR检测试剂盒选择提供了一种可用的评价方法。