小豆遗传差异、群体结构和连锁不平衡水平的SSR分析

利用57对小豆SSR标记和31对绿豆SSR标记,用5份日本材料作对照,对249份中国小豆种质进行遗传差异、群体结构和连锁不平衡(LD)分析。结果表明,共检测到630个等位变异,SSR位点等位变异数在2~17之间,遗传多样性指数范围为0.024~0.898,平均为0.574。15个不同地理来源群体间表现出显著的遗传多样性差异,其中中国云南最高,河北、天津最低。聚类分析将254份材料划分为3个类群,在一定程度上和地理生态环境相关。LD分析显示和其他作物相比,小豆LD衰减距离较短,最大衰减距离为5.8 cM (R²>0.1),基因组LD平均衰减距离小于1 cM (R²>0.1,P<0.001)。     

不结球白菜耐热变异体的生长与移栽及品质分析

以不结球白菜耐热变异体为供试材料，比较了不同浓度蒸糖，IBA和MET对试管苗生长及发根的影响；比较了不同基质，炼苗天数和保湿天数对试管苗移栽成活率的影响；测定了植株叶片的游离氨基酸含量和观察了植株田间的耐热、耐湿及抗病性。实验结果表明，培养基中添加2％蔗糖，0.1mg/L IBA和0.1mg/L MET有益于试管苗的健壮及发根；用珍珠岩作基质，5d炼苗和保湿10d可以提高移栽成活率；耐热变异体中存在氨基酸含量和耐热、耐湿、抗病性比原始品种提高的材料。     

分析中国栽培大豆遗传多样性所需SSR引物的数目

我国拥有极其丰富的大豆资源。传统的方法是根据农艺性状来分析其遗传变异，但农艺性状受自然环境和人为因素影响明显。随着大豆育成品种的增加，有限的表型变异已难以详细阐明我国2万余份大豆品种的遗传变异情况，需要从DNA分子水平深入研究我国大豆资源遗传变异分布规律。本研究以190份为大豆为初选核心种质的一个无偏样本。用60对SSR引物扩增，获得606个等位变异，平均每个位点有10个等位变异。位点多态信息量范围从0．55到0．99，平均为0．83。对190份大豆相似系数矩阵的标准误分析表明。SSR引物数增加到50左右时。再增加引物，标准误变化很小。共表型矩阵之间的相关性测验显示，当等位变异数达到570以上，相互之间相关性极显著。从实验材料中选取东北春大豆类型作为一个小样本进行共表型矩阵相关性分析也有类似结果。用SSR方法分析中国栽培大豆(G．max)遗传变异关系时，只有等位变异数达到一定的范围时，才能真实地反映出品种之间的遗传变异关系。当群体的遗传变异范围变得相对较小时。分析个体之间的遗传变异关系所需的等位变异数目也相应降低。结合SSR位点在大豆基因组中的分布和基因多样性水平。能够找到分析栽培大豆遗传多样性的核心SSR引物。只有获得等位变异数在570以上。才能客观地反映出中国栽培大豆遗传变异关系。     

甜玉米自交系测验种筛选的研究

选用9个普甜玉米（Zea mays L.sacchorata Sturt)自交系作测验种，用新选育的10个普甜玉米自交系作待测系，采用NCⅡ交配设计，对待测系配合力测定中的测验种进行筛选。结果表明：甜玉米自交系可筛选出用于测定甜玉米待测系的产量及农艺性状一般配合力的测验种；对测验种的株高选择不严格，而穗重、穗长、穗粗、行粒数、千粒重、生育期及秃尖长对测验种的选择较严格。     

早熟高产杂交油菜新组合黔杂185丰产稳产性分析

1994年—1996年度贵州省油菜区试的结果,反映了我省杂交油菜育种近年来在早热高产上有较大进展,尤以位居第一的黔杂185最为突出,还兼具适应性广、稳产性强的特点。分析表明:早熟油菜一旦高产,其稳定性也较强。还分析了不同品质产量构成三因素(单株角果数、角粒数、千粒重与产量构成的主次特点,特别对三因素的变异与产量变异的关系作了分类,不同类型的变异关系特点是提出相应的具有针对性的栽培管理措施的根据之一     

新品种预备试验资料的显著性测验方法探讨

国家和省级农作物新品种试验分为预备试验、区试和生产试验三个环节，使新品种试验走上更规范化道路。由于预备试验不需要多次重复，对试验结果采用直观分析法、这种分析方法简单易行，但对结论无概率保证。如果利用试验中对照多次重复结果估计试验误差，并测验各参试品种与对照的显著性，就会得出更符合客观实际的科学结论。     

筛选甜玉米自交系作测验种研究

选用9个普甜玉米（Zea mays L.saccharata Sturt)自交系作测验种，用新选育的10个普甜玉米自交系作待测系，采用NCⅡ交配设计，对待测系配合力测定中的测验种进行筛选。结果表明：甜玉米自交系可筛选出用于测定甜玉米待测系的产量及农艺性状一般配合力的测验种。穗重、穗长、穗粗、行粒数、千粒重、株高及生育期对测验种的选择不太严格；而秃尖长对测验种的选择较严格。     

异附加系数量性状的遗传分析方法

本文根据异附加系的细胞遗传特点结合数量遗传学原理，提出了异附加系数量怀状遗传分析方法。要点如下：（１）以异附加系为被测系、正常品种（系）作测验系，组配成各世代群体；（２）将异附加系分成两类，第一类是杂种分离世代中可区分亚世代，第 是其杂种分离世代中不可区分亚世代；（３）给出了第一类异附加系的各世代（亚世代）的遗传组成，均数分量和变异分量；（４）给出了第二异附加的遗传组成和均数分量。     

航天搭载玉米自交系SP3的变异研究

为了解航天诱变对3个玉米自交系SP3株系在主要性状上与地面同源对照种子的变异情况,研究其变异规律,为其后代的选育和研究提供理论依据。对诱变后代主要性状的变异幅度、变异系数和平均值与对照进行对比,并对性状平均值进行差异显著性测验。3个玉米自交系SP3株系的多数性状均产生明显变异,为选择不同类型的种质材料提供了基础。其中株系株型性状变异偏植株变矮,叶面积变小,利于选择矮杆叶疏的变异材料;果穗性状变异较小,选择意义不大;而生育期和雄穗性状的变异差异较大。航天诱变处理对不同材料不同性状的诱变效果差异较大,应根据具体的育种目标选择适合的诱变材料,从中选择有利的变异。     

水稻孕穗期耐热性QTLs分析

水稻籼粳亚种间杂种优势利用是提高水稻产量的重要途径。然而，异常高温或低温导致籼粳亚种间杂种育性下降是影响其优势利用的主要因素之一。本研究以USSR5（粳稻）/广解9号（籼稻）//USSR5回交群体为供试材料，构建了相应的分子连锁图谱，分别以高温处理下直接小穗育性及小穗育性热敏感指数为指标，对水稻孕穗期高温耐热性及其相对耐热性进行数量性状位点（QTLs）分析。结果表明，在第2、4和5染色体上检测到孕穗期耐热性相关的QTL各一个，对表型变异的解释率为6.4%~15.8%；在第4、8染色体上分别检测到与孕穗期相对耐热性相关的QTL，qhts-4和qhts-8，LOD值分别为3.81和2.86，对表型变异的解释率分别为16.8%和9.9%。对其进一步的上位性分析表明，有8条染色体的4对位点存在基因间互作，小穗育性耐热性除受主效QTL控制外，还受基因间互作及修饰基因的影响。     

回归分析中的模型偏差及其防止

研究了回归分析中的模型偏差(即分析模型和真实模型的差异)对估计数b和[AKY^〗的影响.结果表明,偏差存在时b和都成为有偏的估计数,也不能有效地测验回归均方的显著性.但是,如果在试验的某些水平上适当地设置重复,而试验因子的水平数又多于要估计的回归参数数,就能够有效地防止模型偏差.作为事例,评价了7个回归设计的优缺点.     

Heritability of oil content and the onset of flowering in a population of Dimorphotheca pluvialis

To develop efficient breeding strategies for the improvement of oil content and onset of flowering in Dimorphotheca pluvialis, narrow-sense heritabilities of these characters were estimated. Forty plant progenies were tested in 2 years and heritabilities were estimated from parent-offspring regression as well as from half-sib family variance components analyses. For oil content, the heritabilities estimated by means of parent-offspring regression were 0.36 and 0.33 for 1993 and 1994, respectively. The heritabilities obtained from the variance components analyses were 0.41 and 0.23 for the two years. Heritability estimates for onset of flowering showed more variation. From parent-offspring regression, the heritabilities were 0.72 and 0.37, and from variance component analysis the estimates were 0.53 and 0.19 for 1993 and 1994, respectively. The obtained heritability values and realized responses suggest that particularly in early selection generations, even with mass selection, considerable progress can be expected. Since correlation studies revealed neither phenotypic nor genotypic correlation between oil content and onset of flowering, selection for both characters can be undertaken independently.     

Designing an experiment with quantitative treatment factors to study the effects of climate change

Experiments for studying the effects of climatic change on ecosystems often involve manipulation of one or several quantitative treatment factors of interest. Response surface regression is the method of choice for these types of experiment. Here, we describe the development of a design of a free air CO₂ enrichment experiment with two quantitative treatment factors, that is, elevated temperature and CO₂ enrichment. The design strategy takes account of budget constraints imposing limitations on the number of plots with elevated temperature and CO₂ levels. The approach is based on polynomial regression models and is focussed on an efficient estimation of interaction between the two treatment factors. Extension to more than two factors is straightforward. An analysis of soil moisture data demonstrates the overall suitability of the proposed design to analyse non‐linear interactions of two (or more) global change factors.     

等位基因功能差异的统计遗传学分析及应用

等位基因的变异在各种生物中都是普遍存在的,并对基因的表达起着重要的调控作用。为了探索关联分析中品种数目(A)、平均等位基因多态信息含量(B)和候选基因总贡献率(C)对候选基因分析结果的影响,本研究采用经验贝叶斯(E-Bayes)方法探讨了上述因素对候选基因检测功效、遗传效应估计值的准确度和精确度以及假阳性出现频率等的影响。结果表明,(1) 随着A、B和C的增加,候选基因的检测功效和效应估计值的准确度和精确度明显提高,假阳性出现的频率降低。(2) B对检测功效有显著的影响。在B值保持较高的水平时,即使品种的数目保持较低的水平以及候选基因的总贡献率较低时,平均检测功效也可达到80%;当B值为中等水平时,需要较大品种数目才能使平均统计功效超过80%;当B值较小时,品种数目即使达到100,3种贡献率水平下的统计功效最高也未达到50%。(3) B对候选基因效应估计值的准确度和精确度有显著的影响。随着B的增加,候选基因效应估计的准确度和精确度增加。(4) B因素对假阳性频率也有显著影响。在实例分析中检测到4个基因与稻米糊化温度显著关联。因此,在进行等位基因功能差异的统计遗传学分析时等位基因多态性是主要的影响因素,同时较多的品种数和较高的贡献率对候选基因的统计功效、效应估计值的准确度和精确度也有重要影响。     

A Simple Experimental Analysis Method for Reinforced Concrete Bar System Structures - Sectioned Dropping Rigidity Method

In order to solve the problem that the internal force of statically indeterminate prestressed and reinforced concrete bar system structures is difficut to determine when the structures come to the non-elastic state, a simple analysis method of experimental structures' internal force-sectioned dropping rigidity method is brought forward.In this method, according to the loading state of bars, the bars are divided into limited segments by the level of rigidity dropping, and the relative level of each segment is enacted; then the dropping modulus of each segment rigidity will be found by debugging time after time, and the checking point is the key distortion which was gained from the experiment; it is considered that the internal force which is calculated by elasticity analysis at the dropped rigidity can reflect the real internal force of the structures.It is basically proved that the method, which is brought forward in this paper, is effective by comparing its results with those from the experiment of a large size prestressed frame of two spans and single floor, of which the internal force redistribution is considered.     

Breeding Potential of Root Chicory (Cichorium intybus L. var. sativum)

The objective of this study was to investigate the breeding potential of the inulin-containing root chicory which has potential as a new industrial crop. Polycross families and reference varieties were grown in field experiments at 3 locations to assess their performance and the amount of variation available for breeding. Significant variation between polycross families for all characters except for glucose content and the ratio total sugar/dry matter content was observed. Compared to ‘Fredonia’, 12 out of 72 polycross families gave between 15 % and 24 % more total sugar yield. Preliminary estimates for the heritability of two yield components were calculated by means of the parent-offspring regression analysis. Additive genetic variance seems to determine the inheritance of fructose and total sugar content. All findings suggest that the total sugar yield of root chicory can be considerably increased by breeding.     

Effect of soil disturbance on pedotransfer function development for field capacity

The increasing use of simulation models for design and analysis of land use management options has meant an increased need for detailed soil data. When such data are not available, pedotransfer functions (PTFs) can be used to estimate soil properties such as cation exchange capacity (CEC) and field capacity (FC) from other more readily available data. However, if PTFs for FC have been developed from disturbed samples, there is a doubt as to the accuracy of the prediction for in-situ soils. To determine the effect of soil disturbance on the estimate of FC and the development of PTFs, we determined FC on both disturbed and in-situ samples for soils from four contrasting agro-ecological environments in Mexico. Results suggest that PTFs for FC developed from in-situ samples can be used in simulation modeling, as 89% of the variation across the four contrasting soils was explained; soil organic matter (SOM) being the dominant factor in the function. However, caution is required in using PTFs for FC developed from disturbed soil samples as they overestimated in-situ FC for all soils except for the coarser textured soil. Other PTFs for FC from the literature were evaluated in terms of their qualitative and quantitative estimates of in-situ FC.     

Variation and covariation of agronomic traits and quality in triticale at low nitrogen input

The use of high nitrogen (N) inputs is becoming restricted in many countries due to environmental and economic considerations and reliable information is needed about parameters pertinent for breeding N-use efficient triticales (x Triticosecale Wittmack). This study reports estimates of variances, heritabilities, correlations, and regression for 36 triticales, grown at three locations for 2 years with two N regimes (zero and normal N supply). Eleven traits were assessed. A 45% mean reduction in grain yield by low N input was mainly the result of a 25% lower number of tiller-bearing spikes per m2 and 17% fewer kernels per spike, whereas 1000-kernel weight was little affected. Genotype-nitrogen interaction was of importance only in some environments and for certain traits. Heritability estimates at both N levels were similar and moderate to high. Correlations between N levels were high for nearly all traits. Regression analysis for grain yield revealed only few N-efficient triticales with lower than unity slope together with a high grain yield. Based on the genetic parameters, it is concluded that a special low input breeding programme does not appear to be necessary in triticale. The breeder can select at either of the N levels with similar response. But he should include tests in low productivity environments at some early stages in the breeding process to avoid loss of genetic variation for N-use efficiency.     

数量性状基因的完备区间作图方法

结合分子标记和表型数据的QTL作图已成为数量性状遗传分析的常规方法。复合区间作图是近10多年来广泛应用的一种QTL定位方法,但它在算法上有一些缺陷,致使QTL效应可能会被侧连标记区间之外的标记变量吸收,同时不同的背景标记选择方法对作图结果的影响较大,并且难以推广到上位型互作QTL的定位。针对这些问题,笔者提出完备区间作图方法。本文介绍了该方法的遗传和统计原理,并通过一个大麦加倍单倍体群体说明其在定位加性QTL和加性×加性互作QTL中的应用。完备区间作图包含两个步骤：首先利用所有标记的信息,通过逐步回归选择重要的标记变量并估计其效应;然后利用逐步回归得到的线性模型校正表型数据,通过一维扫描定位加(显)性效应QTL,通过二维扫描定位上位型互作QTL。这种作图策略简化了复合区间作图中控制背景遗传变异的过程,提高了对QTL的检测功效。     

Application of Slicing in Component-based System Regression Testing

In component-based system regression testing, the dependence model of component-based system should be built in order to confirm the part which will be affected by modify. Since high reusability and high complexity, the existing dependence models may not be applicable to component-based systems, a hierarchical dependence model is proposed to describe component-based. Through the forward slicing of modified points in the model, the modified and affected parts can be gotten, then traverse these parts and get affected testing path, thereby regression testing examples can be chosen effectively, the efficiency of regression testing can be improred.