A comparative analysis of the genetic relationships between rye cultivars using RFLP and RAPD markers

Summary The genetic similarities of eight closely related rye cultivars were estimated using two molecular marking techniques: restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD). Cultivars were evaluated for variation by 11 random cDNA and genomic clones used in combination with four restriction enzymes and 40 decamer primers. A total of 53 polymorphic RFLP fragments and 94 polymorphic RAPD fragments were observed. Based on the presence/absence of fragments, two genetic similarity matrices were calculated which were then used in cluster analysis. Differences between pair of cultivars were observed in RFLP and RAPD dendrograms. RFLP analysis produced estimates of genetic relationships more in accordance with the partially known pedigree of the cultivars than did RAPD analysis. The use of bulk samples of DNA in these analyses affected the sensitivity of RAPD assays more strongly. Dendrograms which took into account all fragments produced, either by RFLP or RAPD, reflected better the relationships between cultivars than did dendrograms based on only one type of marker. This reflects the importance of the number of markers used in determining the genetic relationships between genotypes.     

Sulfoxaflor and the sulfoximine insecticides: Chemistry,mode of action and basis for efficacy on resistant insects

The sulfoximines, as exemplified by sulfoxaflor ([N-[methyloxido[1-[6-(trifluoromethyl)-3-pyridinyl]ethyl]-λ⁴-sulfanylidene] cyanamide] represent a new class of insecticides. Sulfoxaflor exhibits a high degree of efficacy against a wide range of sap-feeding insects, including those resistant to neonicotinoids and other insecticides. Sulfoxaflor is an agonist at insect nicotinic acetylcholine receptors (nAChRs) and functions in a manner distinct from other insecticides acting at nAChRs. The sulfoximines also exhibit structure activity relationships (SAR) that are different from other nAChR agonists such as the neonicotinoids. This review summarizes the sulfoximine SAR, mode of action and the biochemistry underlying the observed efficacy on resistant insect pests, with a particular focus on sulfoxaflor.     

玉米株型和幅宽对套作大豆碳氮代谢及产量的影响

在玉/豆套作模式下,采用玉米株型与种植幅宽二因素裂区设计,研究了不同田间配置对套作大豆碳氮代谢与产量的影响。结果表明,较大幅宽和紧凑型玉米下,大豆被荫蔽的程度有所减缓,碳氮代谢变化趋势朝着利于产量形成的方向发展。主要表现为,茎叶中的碳氮含量和关健酶在各时期保持在较高的水平;R4期后叶片中的淀粉迅速降解为糖运至籽粒,而氮的下降速率缓慢。结合前期的研究,我们得出,R2是大豆经历光照转换的重要时期,该时期植株的碳氮代谢能力对大豆后期产量的形成起着重要的作用。而R6期大豆表现出来的碳、氮代谢水平,又能一定程度的反映产量水平。本试验条件下,对玉米、大豆两季作物的经济效益进行分析后得出,利于大豆生长,且保证全年高产,高效的最优组合为：与紧凑型玉米套作,大豆幅宽1.17m,玉米幅宽0.83m。     

梅花不同样本间亲缘关系的AFLP初步分析

 应用AFLP技术初步研究20个梅花株系间的亲缘关系，19对选择性引物扩增出清晰的总位点数918个，其中多态性位点324个，占总位点数的35.29%。采用SAS类平均法聚类分析AFLP数据，λ值为0.9759时，将20个梅花株系分为4个类群。半野生种曲梗梅的多态性位点数最高，'多萼朱砂'、'复瓣小宫粉'等梅花品种次之。在类群Ⅳ中，具有明显亲缘关系的两组亲本及其杂交子代各自聚为一组，表明AFLP技术和聚类分析方法可以用来研究梅花品种间的亲缘关系。'小宫粉'、'江南朱砂'和它们的子代亲缘关系密切，结果仍能区别其较小差异，这有助于解决梅花中存在的不同产地相同品种异名和同名而品种不同的问题。垂枝类梅花品种间有较近的亲缘关系或者遗传来源，支持枝姿作为梅花分类的重要形态特征，垂枝类品种属于梅花中比较进化的类群与其历史演化相吻合。本研究中所采用的DNA限制性内切酶酶切组合及所筛选的AFLP选择性引物对适合研究梅花品种间的亲缘关系和遗传多样性。     

白僵菌有关培养条件及其与毒力关系的研究

以麦麸、米糠、黄豆粉、蛋白胨、牛肉膏、蚕蛹粉作供试氮源,在３种动物性氮源的培养基上,白僵菌的产孢量及毒力均高于植物性氖源,其中以蚕蛹粉最优;在１６种不同碳氮比的培养基上,以碳氦比２（４０／２０）和１．５（３０／２０）产孢量和毒力为高;在８种不同ｐＨ值的培养基上,以ｐＨ５．５～６．５最适于产孢,ｐＨ６．３、７．０时,白僵菌的毒力明显较强。研究结果显示,菌落生长量和产孢量往往不一致,而产孢量与毒力则明显相关。     

兰花基因组DNA多态性RAPD分析

利用随机扩增多态DNA技术(RAPD)对兰属的3个品种春兰、春剑、蕙兰进行了分析与研究,建立了它们之间的DNA指纹图谱,找到了参试样品的特征谱带,并探讨它们之间的亲缘关系.结果从20条BA系列引物中筛选出能稳定扩增的10个引物,且对3个品种的植株进行扩增,共扩增出257条,其中243条具有多态性,分析结果表明春剑与春兰的相似系数较之与蕙兰的相似系数要高.     

AFLP初析小豆栽培和野生变种(Vigna angularis var.angularis and var.nipponensis)间演化与地理分布关系

 利用 12对AFLP引物 ,以饭豆标准品系M 0 0作对照 ,对来自中国、日本、韩国、尼泊尔、印度、不丹的 14 6份小豆栽培种 (Vignaangularisvar.angularis)和野生种 (Vignaangularisvar.nipponensis)种质的基因组DNA进行扩增 ,得到 313条多态性带。据AFLP多态性数据绘制的聚类图 ,可区分其中的 14 3份种质 ,表明小豆物种 (Vi gnaangularis)存在足够的遗传多样性 ,可用于资源材料的准确鉴别与分类。鉴于此 ,采用新开发的利用AFLP数据揭示核苷多样性的Innan’s进化树分析方法 ,进一步将 14 6份小豆资源分成 7个明显不同的地理演化群 ,即中国栽培种、日本栽培种、日本综合群 韩国栽培种、中国台湾野生种、中国野生种、尼泊尔 不丹栽培种和喜马拉雅野生种演化群。就上述地理演化群的遗传多样性、地理分布以及野生种与栽培种之间可能的演化关系进行了分析 ,初步认为栽培小豆至少应当有 4个不同类型的野生祖先和 3个不同的地理起源。     

Unknown‐parent groups in single‐step genomic evaluation

In single‐step genomic evaluation using best linear unbiased prediction (ssGBLUP), genomic predictions are calculated with a relationship matrix that combines pedigree and genomic information. For missing pedigrees, unknown selection processes, or inclusion of several populations, a BLUP model can include unknown‐parent groups (UPG) in the animal effect. For ssGBLUP, UPG equations also involve contributions from genomic relationships. When those contributions are ignored, UPG solutions and genetic predictions can be biased. Options to eliminate or reduce such bias are presented. First, mixed model equations can be modified to include contributions to UPG elements from genomic relationships (greater software complexity). Second, UPG can be implemented as separate effects (higher cost of computing and data processing). Third, contributions can be ignored when they are relatively small, but they may be small only after refinements to UPG definitions. Fourth, contributions may approximately cancel out when genomic and pedigree relationships are constructed for compatibility; however, different construction steps are required for unknown parents from the same or different populations. Finally, an additional polygenic effect that also includes UPG can be added to the model.     

Modelling dimensional growth of three street tree species in the urban forest of the City of Tshwane,South Africa

Tree height, crown height, crown diameter and stem diameter were measured for 282 trees of the indigenous species Combretum erythrophyllum, Searsia lancea and S. pendulina. Growth relationships were modelled using age as explanatory variable for stem diameter and subsequently stem diameter as explanatory variable for tree height, crown height and crown diameter. Coefficients are presented for predicting tree dimensions using a logarithmic function. There were strong correlations for stem diameter and age (r ² ≥ 0.75), and crown diameter and stem diameter (r ² ≥ 0.74) for all three of the species investigated. Correlations were weaker for tree height and stem diameter (r ² ≥ 0.63), and crown height and stem diameter (r ² ≥ 0.60) for S. pendulina but stronger for both C. erythrophyllum (r ² ≥ 0.83) and S. lancea (r ² ≥ 0.70) in both instances. The results can be used in forecasting the physical dimensions of these species as a function of time. The results could also be used in the process of modelling energy use reduction, air pollution uptake, rainfall interception, carbon sequestration and microclimate modification of urban forests such as those found in the City of Tshwane.     

不同性别类型黄连木的花序类型与分布及亲缘关系

利用筛选的14对SSR标记对9株雌雄同株黄连木上不同类型的花序进行基因型稳定性研究,同时对河南和河北地区140份黄连木样本进行UPGMA聚类分析,以探究其亲缘关系。结果表明:在河南马鞍山和西齐地区,雌雄同株树上两性花的数量多于混合花序的数量,雌花序和雄花序数量基本相等;而在河北老姑和杨家庵地区,混合花序的数量多于两性花的数量,雌花序的数量多于雄花序。雌雄同株树上不同类型花序的DNA条带没有差异,表明不同性别类型在同一株树上的可变表达不是DNA变异造成的。聚类结果表明,河南马鞍山和西齐地区3种性别类型黄连木样本的亲缘关系均较近;河北老姑和杨家庵地区雌雄同株树与雌雄同株树、雌树亲缘关系较近;来自不同地区的不同性别类型黄连木之间均表现出较近的亲缘关系,无明显的地域性。