团头鲂与三角鲂或长春鳊杂交后代的生长及形态对比分析

为了解鳊鲂鱼类及其杂交子代的生长状况及形态差异,对鲂属(Megalobrama)团头鲂(AA)、三角鲂(TT),鳊属(Parabramis)长春鳊(PP)自交群体及其杂交子代(AT、TA、AP和PA)共7个群体进行了生长对比,并运用多元统计方法对繁殖后代的生长性状、可数性状、可量性状和框架性状的形态学差异进行分析。在实验组1中,AA绝对增重率最高(0.36 g/d),分别是TT(0.15 g/d)、AT(0.30 g/d)和TA(0.27 g/d)的2.4倍、1.2倍和1.3倍,且AT和TA绝对增重率显著高于TT(P0.05)。在实验组2中,AA绝对增重率显著高于其他组(P0.05),分别是PP(0.14 g/d)、AP(0.17 g/d)和PA(0.15 g/d)的1.7倍、1.4倍和1.6倍。结果表明,团头鲂(AA)的生长速度显著快于三角鲂(TT)和长春鳊(PP)自交群体(P0.05),AT、TA、AP和PA这些杂交后代的生长速度基本介于双亲之间,即低于团头鲂而高于三角鲂或长春鳊。对9项可量性状和20项框架参数的聚类分析结果表明,杂交后代的主要形态特征较为接近母本,即TA与TT的亲缘关系较近,AT和AP与AA的亲缘关系较近,PA与PP关系较近。对7个群体进行判别分析,结果显示其综合判别率为86.30%。主成分分析获得了表示形态差异的3个主成分,其累计贡献率为95.81%,主成分1特征向量绝对值较大的各性状大多集中在鱼体的纵轴,即背腹轴方向,而主成分2性状大多集中在尾部,反映了尾部的体型特征。本研究为鳊鲂鱼类的杂交育种以及种质鉴别提供了基础资料。     

广义复相关系数及其在小麦育种上的应用

为了解决多个因变量Y和多个自变量X之间的相关分析,假设X与Y的联合正态分布已知,而且X与Y存在线性相依,提出广义复相关系数的定义、估计和检验。广义复相关系数是简单相关系数和复相关系数的自然推广,应用上更为方便。     

基于几何形态测量法的剑尖枪乌贼角质颚形态变化研究

研究生物体的个体发育有助于充分认识其个体形态变化规律,从而了解生物体结构的功能性与形态间的相关关系。为探究剑尖枪乌贼(Uroteuthis edulis)角质颚的生长变化规律,本研究使用几何形态测量学方法分析了不同性别及发育阶段角质颚大小和形态的差异,并揭示其背后的生态含义。结果显示,剑尖枪乌贼不同性别个体的角质颚大小在发育过程中存在一定差异,雌性个体角质颚大于雄性个体,但不同性别角质颚形态差异不显著(P>0.05)。主成分分析和薄板样条变形网格显示,角质颚形态由未成熟至成熟期呈渐变规律。在发育过程中,上、下颚的头盖和翼部变得更大,脊突更加凸出,颚角夹角逐渐变小;上颚喙部更加尖锐,但下颚喙部逐渐变得迟钝。多元回归分析显示,上颚在未成熟期形态变化较小,在亚成熟期和成熟期变化较大,亚成熟期和成熟期形态变化趋势相似;下颚在未成熟期和亚成熟期形态变化较大,成熟期形态变化较小,发育过程中形态变化趋势差异较大。研究表明,剑尖枪乌贼在发育过程中,角质颚形态随着其个体不断发育呈渐变规律,同时,角质颚存在异速生长现象,可能与剑尖枪乌贼发育过程中的摄食和环境变化有关。     

Rice quality profiling to classify germplasm in breeding programs

The objective of this work was to define a quality space for assessing rice varieties. Eleven long grain varieties, seven commercial and four new advanced lines were assessed to obtain complete quality profile considering appearance, physicochemical parameters, water absorption behaviour, pasting profile and textural attributes. Commercial varieties were chosen to provide the widest variation in properties, applying the variability analysis concepts of the Taguchi method, including Japonicas, Indicas, hybrids and aromatics. Quality parameters were measured in five different dimensions of quality space (totalling 50). Variable reduction techniques were applied to chose 3 parameters in each dimension (totalling 15 quality indicators) that would describe the whole space with greatest orthogonality, accuracy and yet explaining a significant proportion of the whole variance of data. The analysis of the quality space thus defined and similarities between varieties is illustrated with the conclusion of how the 4 new advanced lines perform in terms of quality behaviour, where it is concluded that one of them is very promising as an improvement over European (Indica) towards the behaviour of a pure Guyana (Indica), whereas 3 others have significant shortcomings in various aspects of the quality space compared to all others, albeit their greater closeness to Japonicas.     

Rates of piscivory predict pharyngeal jaw morphology in a piscivorous lineage of cichlid fishes

The pharyngeal jaw apparatus is a key innovation hypothesised to increase foraging efficiency and facilitate utilisation of novel resources among teleost fishes. Here, we tested whether dietary characteristics could predict pharyngeal jaw morphology among eight species of Neotropical Crenicichla. Additionally, we tested the hypothesis that pharyngeal jaws may impose a functional constraint on piscivory via pharyngeal gape. We quantified the shape of the lower pharyngeal jaw (LPJ) using linear and geometric morphometrics and quantified diet using the relative volumetric proportions of prey items. We used principal component analysis to describe major axes of variation in LPJ shape and dietary patterns. The major axis of dietary variation significantly predicted LPJ morphology, which was driven by a significant relationship between LPJ shape and rates of piscivory. We also found that rates of piscivory predicted size‐corrected LPJ depth. Size‐corrected pharyngeal gape also significantly predicted rates of piscivory such that pharyngeal jaws may constrain piscivory by limiting pharyngeal gape. Strong form‐to‐function linkage between pharyngeal morphology and trophic patterns suggests an adaptive quality of the pharyngeal apparatus but may also impose functional constraints when consumers must switch prey or when prey availability is temporally or spatially unpredictable.     

基于多元回归的牡丹花期预测

利用菏泽牡丹多年的气象要素的测定资料,采用多元回归以及逐步回归法,建立了气温、地温与牡丹花期关系的线性回归模型。该模型的预测结果与牡丹的实际盛花期基本吻合。该模型为确定菏泽牡丹花会的召开提供了依据。     

多元统计分析棉花品质性状的研究

[目的]探讨棉花纤维品质的基本动态与总体特征。[方法]以黄河流域区试的17个杂交春棉品种为材料,对其纤维品质性状进行相关分析、主成分分析、聚类分析与多元方差分析。[结果]各项纤维品质性状的变异系数从大到小依次为:麦克隆值>黄度>纺纱指数>比强度>纤维长度>反射率>伸长率>整齐度。前3个主成分方差累积贡献率达90.84%,第1主成分、第2主成分、第3主成分的方差贡献率分别为49.10%、25.36%和16.38%,依次为纤维品质综合因子、伸长率因子和整齐度因子。按纤维品质的相似度,聚类分析将17个杂交春棉品种划分为4大类。[结论]第Ⅰ类为优质棉品种,第Ⅱ类为亚优质棉品种,第Ⅲ、Ⅳ2类为中质棉品种。     

A study on the measurement for forest ecological benefit

IntroductionForesaw is importsnt part of national economy, notonly an industry but also a public welfare. Forestresource has ecological, economical and socialb6nedtS. At present, the study about forest ecologicalbenefit is mainly on measurement of physical quanhty, and less on measurement of economical quantity(Bat6man 1991, DWyer et al. 1992.) (how to transformphysical quantity to economical quantity). There existmany problems on research of measurement of forestecological benefitS. For ex…     

姬松茸辐射选育新株系数量性状的多元遗传分析

以9个姬松茸品种和辐射选育新株系为材料,对其进行数量性状的多元遗传分析。结果表明:遗传变异系数最大的数量性状为柄重,达到25.39%;其次为朵重,变异系数为17.70%;再次为盖重,变异系数为15.29%;变异系数最小为盖厚,只有6.14%。子实体中的各类氨基酸总量和农艺各性状之间存在一定的相关性,部分性状间相关性达显著至极显著。遗传主成分分析结果表明,14个性状可以缩减为4个主成分,遗传变异贡献率大小分别为44.21%、37.70%、8.47%、5.67%,总贡献率达96.05%。