小型西瓜核心种质构建

丰富的种质资源为作物育种和遗传研究提供了广阔的遗传基础,然而近年来急剧增加的种质资源数量给种质资源的保存、研究与利用带来了很大困难。构建核心种质为种质资源的研究和利用提供了便利条件。以410份小型西瓜种质资源为试验材料,基于6个果实性状数据,采用混合线性模型分析方法无偏地预测基因型值,计算种质间的遗传距离,采用不加权类平均法进行聚类分析,按照20%的抽样比率构建小型西瓜核心种质库。采用均值、方差、极差和变异系数4个指标评价核心种质库的优劣。结果表明,马氏距离优于欧氏距离,偏离度取样法优于优先取样法,基于马氏距离和偏离度抽样方法获取的82份核心资源能够代表原群体的遗传多样性。为小型西瓜种质资源的高效利用提供了重要理论依据。     

利用基因型值构建宁夏粳稻核心种质的方法

以250份宁夏粳稻为材料,根据7个农艺性状的遗传多样性,研究粳稻核心种质的构建方法.采用混合线性模型统计分析方法无偏预测材料各性状的基因型值,根据2种遗传距离(马氏距离和欧氏距离),3种取样方法(多次聚类随机取样法、多次聚类优先取样法、多次聚类偏离度取样法),8种聚类方法(最短距离法、最长距离法、中间距离法、重心法、类平均法、可变类平均法、可变法、离差平方和法),用均值、方差、极差、变异系数及秩次评价不同遗传距离、取样方法、聚类方法的优劣.结果表明,马氏距离优于欧氏距离;偏离度取样法优于优先取样法和随机取样法,聚类方法最好的是最短距离法、可变类平均法,适宜取样比例是15％.用马氏距离、偏离度取样法、15％取样比例、最短距离聚类法构建了37份宁夏粳稻核心种质.     

基于区间分析的框架结构不确定性损伤识别方法

考虑实际结构易受荷载、环境温度和测试噪声等不确定性因素的影响,笔者基于区间分析原理提出框架结构不确定性损伤识别方法。利用测试的结构加速度响应数据,建立向量自回归模型,并采用其系数矩阵主对角线的马氏距离作为损伤特征指标。基于粒子群算法建立区间优化求解方法,并与传统的区间组合法和区间叠加法对比。通过提出的区间重叠率指标和区间名义值分别实现损伤定位和损伤程度的识别。数值模拟和实验室框架结构试验结果表明,区间分析能在测试数据较少时实现损伤识别,为损伤识别在实际结构中的应用提供了理论基础和技术手段。     

基于NDVI的绿洲棉田土壤肥力质量评价方法研究

以天山北坡典型国营农场棉田为研究对象,探讨基于归一化植被指数(NDVI)的棉田土壤肥力质量评价方法.将棉花不同生育期表征长势的NDVI作为评价指标对棉田土壤肥力质量进行评价,再将NDVI与少量理化测定的土壤样点数据(有机质、有效磷含量等)共同作为评价指标,结合地统计方法与遥感影像聚类算法进行评价;并与完全基于土壤样品理化测定数据的评价结果进行比较、探讨基于NDVI评价方法对土壤肥力质量评价结果的准确性与可靠性.研究证明将NDVI与少量理化测定的土壤样点数据作为评价指标,能显著提高评价结果与棉田实际土壤肥力状况的一致性.基于NDVI的土壤肥力质量评价方法快速、简便,其评价结果可为研究绿洲棉田土壤质量及农业结构调整规划、耕地质量保护等提供科学依据.     

PI模型在乌兰察布市土壤生产力评价中的适用性研究

为了给乌兰察布市土壤生产力评价提供一种简单、实用、客观的评价方法,在PI模型及后人修正的PI模型(MPI)的基础上,结合研究区土壤特点,对PI模型进行了修正(MPI-Ⅱ),主要修改了MPI模型中有机质指标的计算方法,并增加了碳酸钙指标。利用MPI模型和MPI-Ⅱ模型,评价了43个土种的土壤生产力,并与研究区第2次土壤普查中综合评价法的评价值进行了比较。结果表明：（1）MPI-Ⅱ模型的评价值与综合评价法的评价值之间的相关性(R2=0.589,P<0.01)比MPI模型与综合评价法之间的相关性(R2=0.305, P<0.01)高,MPI-Ⅱ的评价值可能更接近研究区的实际情况;（2）总体而言,MPI-Ⅱ模型的评价值与综合评价法的评价值较一致,但有5种土壤的评价值差异较大,可能是综合评价法的主观性较强所致。因此,MPI-Ⅱ模型对研究区的土壤生产力评价可能有较好的适用性。     

基于欧氏距离理论的农业可持续发展评价方法与实证研究

基于欧氏标准化距离理论,构建了农业可持续发展评价理论体系与评价指标框架,包括评价函数、评价等级、评级指标、佳态系统与原点系统等。选取甘肃镇原县、宁夏吴忠市和山东桓台县2000-2012年数据作为实证案例,并在评价指标框架下构建评价指标体系,对3个不同类型的农业系统进行了验证性评价。结果表明：甘肃镇原县ASDI(可持续发展指数)范围[0.70,0.83],呈上升趋势,处于中持续与高持续状态;宁夏吴忠市ASDI范围[0.40,0.77],呈波动较大,6年处于非持续、其余年份主要处于中持续状态;山东桓台县ASDI [0.53,0.71],大部分年份小于0.6,处于不可持续状态。欧氏距离法评价结果与农业系统实际情况接近,分别代表了3类农业生态系统。甘肃镇原在有机废弃物(秸秆与畜禽粪便)还田利用、人均粮食、高职教育、人均收入、饮用水安全、农药施用与基尼系数等方面接近佳态系统,仅在氮磷施用上稍微超标,属物质良性循环类型;宁夏吴忠由于在作物单产、有机废弃物还田与人均粮食等方面接近佳态,但在施肥量、水体污染与土壤有机质等方面远离佳态,因而ASDI有较大波动,属传统与集约化并存类型;山东桓台水肥药投入水平较高,农业面源污染负荷大,导致地表水、地下水氮磷超标引起ASDI较低,属典型的集约化类型。     

重要胡麻栽培品种的抗旱性综合评价及指标筛选

以15份国内胡麻栽培品种为材料, 设自然降雨和正常灌水2个处理, 考察与抗旱性相关的7个农艺性状、8个生理生化指标及产量指标, 采用综合抗旱系数、因子分析、隶属函数、聚类分析和灰色关联度分析相结合的方法, 对其抗旱性进行综合评价、抗旱型划分和评价指标筛选。结果显示, 相关性状指标对干旱胁迫的反应及关联程度各异, 可优先选择与抗旱性关系密切的产量及其相关性状、光合作用因子、叶片抗氧化因子等相关生理生化性状;因子分析表明, 6个公因子可代表胡麻抗旱性90.89%的原始数据信息量。基于抗旱性度量值(drought resistance comprehensive evaluation values, D值)和加权抗旱系数(weight drought resistance coefficient, WDC值)的各品种抗旱性排序相近, 位居前6位的抗旱品种相同。各品种D值与综合抗旱系数(comprehensive drought resistance coefficient, CDC值)、WDC值、产量抗旱系数(yield drought resistance coefficient, Y值)之间均呈极显著正相关, 而各品种Y值与CDC、WDC值间极显著正相关;据D值将供试品种划分为5个抗旱级别, 可较好地反映品种的选育条件及适应地区。试验结果说明以D值为主要参数, 以WDC为辅助评价参数, 评价以产量为主要考量目标的胡麻抗旱性是适宜且准确的;以抗旱性综合评价方法进行胡麻抗旱性综合评价、抗旱型划分、评价指标筛选是准确的。     

普通菜豆品种苗期抗旱性鉴定

以不同来源的普通菜豆品种为材料,采用盆栽法,设正常供水和反复干旱2种处理,测定11项生理指标,采用灰色关联度理论进行苗期抗旱性指标筛选,通过加权抗旱指数(weighted drought-resistance index,WDI值)和抗旱度量值D(drought resistance comprehensive evaluation values,D值)对供试材料进行抗旱性综合评价并通过聚类分析划分抗旱等级。结果表明,不同指标与综合抗旱指数的关联度大小依次为叶片相对含水量(0.7726)、PSII最大量子产量(0.7607)、叶绿素含量(0.7435)、反复干旱存活率(0.7341)、生物量(0.7329)、茎叶干重(0.7314)、根干重(0.7192)、气孔导度(0.7159)、根冠比(0.7092)、株高(0.7086)、叶面积(0.6910)。基于加权抗旱指数和抗旱度量值D的评价结果存在一定差异,但不同材料的抗旱性排序大体一致。根据抗旱度量值D将供试材料分为高抗、中抗、敏感和高敏感4个级别,各占总数的10%、6%、58%和26%。综上所述,叶片相对含水量、PSII最大量子产量和叶绿素含量等10项指标可用于普通菜豆苗期抗旱性综合评价;加权抗旱指数与抗旱度量值D两种综合指标相结合能够提高鉴定结果的可靠性;50个参试普通菜豆品种中,白金德利豆、跃进豆、兔子腿、圆白菜豆和260205抗旱性强。     

粮食酸度回收率测定方法的首次探讨

首次探讨了粮食酸度回收率的测定方法,为评价粮食酸度测定结果的准确性提供了依据。采用2台JDDY型自动滴定分析仪分别测定面粉酸度的回收率,实验结果表明,回收率在97.4%~109.7%之间,测试值与理论添加值之间具有较好的相关性,线性相关系数分别为r=0.9986、r=0.9992,能够满足目前粮食酸度指标的品质检验要求。     

安徽省各茶区茶树品系遗传多样性分析及指纹图谱构建

为了解安徽省参加品比试验的各茶区茶树品系的遗传多样性,选取50对SSR引物对安徽省各茶区68份茶树品系进行分析,共检测出650个等位基因,平均每对引物的等位基因数为13个,50对引物扩增的片段长度在95～370 bp,有效等位基因(Ne)值为1.05～17.22,平均为6.10;观测杂合度(Ho)值为0.00～0.99,平均为0.38;期望杂合度(He)值为0～1,平均为0.62;各引物的Shannon信息指数(I)值为0.12～3.06,平均为1.86;多态信息含量(PIC)值变化范围在0.04～0.94,平均为0.72;基因流(Nm)值为0.11～4.45,平均为1.03。选出8对核心引物组合,构建DNA指纹图谱。聚类结果表明,68份茶树品系的居群可聚成3类,与居群的地理分布有一定的相似性,地理距离越近的品系,遗传一致度越大。利用SSR分子标记技术可以为安徽省茶树良种的改良和保护提供参考。     

不同遗传距离聚类和抽样方法构建作物核心种质的比较

以棉花种质资源168个基因型，5个纤维性状[2.5%跨长(mm)、整齐度(%)、强度(gf/tex)、伸长度(%)、麦克隆值]数据为例，用混合线性模型分析方法无偏地预测基因型值，利用得到的基因型值，分别采用2种遗传距离(马氏距离和欧氏距离)和7种系统聚类方法(最短距离法、最长距离法、中间距离法、重心法、类平均法、加权配对算术平均法     

Genetic differentiation and diversity upon genotype and phenotype in cowpea (<Emphasis Type="Italic">Vigna unguiculata</Emphasis> L. Walp.)

The evolution of species is complex and subtle which always associates with the genetic variation and environment adaption during active/passive spread or migration. In crops, this process is usually driven and influenced by human activities such as domestication, cultivation and immigration. One method to discover this process is to analyze the genetic diversity of those crops in different regions. This research first assessed the similarity and differentiation between genetic diversity of genotype and phenotype in 768 world-wild cowpea germplasm which were collected by USDA and US breeding programs. Totally 1048 genotyping by sequencing (GBS) derived single nucleotide polymorphisms (SNPs) and 17 agronomic traits were used to analyze the genetic diversity, distance, cluster and phylogeny. The group differentiation was analyzed based on both the genotype distances from 1048 SNP markers and the phenotypic (Mahalanobis) distance D2 from 11 traits. A consistent result of diversity in genotype (polymorphism information content, PIC) and phenotype (Shannon and Simpson index) indicated that the East Africa and South Asia sub-continents were the original and secondary regions of cowpea domestication. Both dendrograms built by genetic distance present relationship among different regions, and the Mantel coefficient showed medium correlation level (r = 0.58) between genotype and phenotype. The information of both genotypic and phenotypic differentiations may help us to understand evolution and migration of cowpea more comprehensively and also will inform breeders how to use cowpea germplasm in breeding programs.     

Temporal stability of multivariate genetic divergence in cacao ( Theobroma cacao L.) in Southern Bahia conditions

Stability of the genetic divergence among five non-commercial cacao cultivars at advanced ages was investigated over a five-year period (1986–1990). Cluster analysis was performed on five yield components measured on harvests from each crop year and on the data pooled over five years. The temporal stability was assessed by using clustering procedure, which involved the calculation Mahalanobis distance (D²) and of Tocher's algorithm applied to the distance matrix. The comparison of D² and of clusters based upon pooled analysis, and taken as the standard, with D² values and clusters obtained from each year showed a stable clustering pattern in the most favourable year. For the rest of the years, inconsistency in number and composition of clusters formed was observed. An optimum environment was shown to be important for better expressing divergence by D². Consequently, the evaluation of the genetic divergence among the studied cultivars may be conducted based on a single favourable year. This will result in considerable savings in man power, financial resources, and time which would be wasted should the evaluation be extended for several years.     

7个粳稻SSR和SRAP分子标记遗传距离比较及其与产量性状杂种优势的关系

本研究选用产量性状有显著差异的7个粳稻品种,按照Griffing双列杂交方法Ⅳ配制21个杂交组合,用SSR和SRAP分子标记分析亲本遗传距离及其与粳稻产量性状杂种优势问的关系,并比较分析两种分子标记在估算遗传距离时的差别.结果表明,每对SSR引物产生1～11条多态性带,平均3.8条,而每对SRAP引物组合产生1～15条多态性带,平均5.2条.SRAP引物所扩增的条带数和多态性何点数分别是SSR引物的3.3倍和1.3倍.两种分子标记对遗传相似系数较小的品种进行聚类分析时可获得一致的结果,但对遗传相似系数较大的品种进行聚类分析时所得结果并不一致;粳稻产量性状杂种优势的表现大小因件状和杂交组合不同而异;F_1杂种产量性状的表现与亲本自身的性状特点和互补关系密切,用SSR和SRAP分子标记遗传距离难以预测粳稻杂种后代的产量表现和杂种优势强弱.     

构建作物种质资源核心库的一种有效抽样方法

本文提出了基于基因型值构建作物种质资源核心库的抽样方法。 采用包括基因型与环境互作的遗传模型及混合线性模型统计分析原理, 无偏预测基因型值。 用基因型值计算基因型间的马氏距离, 并采用不加权类平均法进行聚类。 根据树型图, 确定合理的分类水平, 将群体分成若干不同的类群。 计算各基因型的平均离差度, 在各类     

基于SNP分子标记的泰山/泰科麦系列小麦遗传解析

对不同年份育成的21个小麦品种（系）进行全基因组扫描,通过分析遗传距离和染色体区段/位点,明确其亲缘关系远近和遗传差异。分析可知,获得的2029个SNP基因位点在B基因组拥有较高的遗传多样性,其次是A和D基因组;在7个同源群中,第3和第6同源群呈现出较高的遗传多样性,而第1和第4同源群的遗传多样性较低;21条染色体中,3A、1B、6B染色体的遗传多样性较高,而1A、6A的遗传多样性偏低。对21份供试材料依据审定（育成）年份分析其群体的平均遗传距离,不同年份品种间的平均遗传距离先增大后减小,遗传多样性逐渐降低;21份供试材料间的遗传相似系数在0.69~0.99之间,大致可聚为4个类群,同一年份的品种一般聚在一起,与其系谱关系吻合。构建并分析供试材料的基因型图谱发现,00s、10s和现在育成的小麦品种（系）共有SNP和共有染色体区段分别主要在A、D和B基因组,对应已发表性状同不同年份育种目标吻合。同时发现21份供试材料均含有25个共同SNP位点,分布在1A、5A、6A、7A、2B、3B、6B、1D、2D、3D和7D染色体上,且每条染色体上分布的SNP位点数目均不相同,通过对应已发表性状进一步证实在品种（系）组配与选育过程中注重产量、株高、分蘖数、抽穗期、灌浆速率和抗病等性状的选择。以上研究结果可为今后小麦新品种组配和选育提供参考依据。     

Estimation of genetic distance and its predictability of F<Subscript>1</Subscript> hybrid performance in barley

Heterotic performance of hybrids is dependent upon the amount of genetic variability among parents and combining ability of alleles at the loci associated with target traits. This study was carried out to determine if (1) pedigree-based genetic distance could explain molecular levels of genetic diversity, and (2) molecular marker-based genetic distance could predict the degree of hybrid performance in barley. The average value of Random Amplified Polymorphic DNA (RAPD)-based genetic similarity for all 58 genotypes was 0.641. Twenty-two hulless barley and eight malt barley varieties showed low levels of genetic diversity with higher similarity values than the average of all or of the hulled barley variety pool. Coefficients of parentage (COPs) computed for 1,653 pairs of 58 Korean barley varieties ranged from 0 to 0.984 with a mean of 0.048. Correlation between the genealogical and RAPD-based genetic similarity matrices was 0.256 (P < 0.01). Correlation values for the related and for all (related + unrelated) genotype pairs were almost similar to each other, indicating that the unrelated genotypes share a large portion of genomes alike in state, not identical by descent. RAPD-based genetic similarity estimates among parents were poorly correlated with their hybrid performance such as 1,000-grain weight (r = 0.34), biomass yield (r = −0.12), and grain yield (r = −0.04) for 11 genotype pairs of hulled barley. However, correlations between heterozygosity at marker loci and hybrid performance for biomass and grain yield slightly increased when two F1 hybrids were excluded in the analysis due to their low yield.     

Simulation of wheat growth using the 3D root architecture model SPACSYS: Validation and sensitivity analysis

SPACSYS, a model of C and N cycling in the soil–plant–atmosphere continuum that incorporates a detailed three-dimensional root growth sub-model, was tested for its ability to predict the growth and root length density (RLD) distribution of winter wheat. The root growth sub-model was parameterized using published or unpublished data for wheat and barley, and validated against an independent data-set from field experiments on wheat in the UK published in 1978. The model reproduced the experimental results well, accurately simulating total above-ground (r = 0.98) and root (r = 0.96) biomass. There was a slight tendency to over estimate root biomass before the start of stem extension and the rate of root loss after anthesis, suggesting that the partitioning coefficient for dry matter between shoot and root system overwinter and the rate of root mortality and the root decay constant after anthesis may require some adjustment. Simulations of rooting depth and RLD distribution over the season were also acceptable. Further simulation work investigated the sensitivity of root length and relative distribution in the soil profile to changes in specific root morphological traits. The total length of the root system was sensitive to changes in traits regulating the number of lateral branches a given root order can produce (the inter-branch distance, the maximum length of root and its apical non-branching distance) and the elongation rate of main axes. The distribution of the root system was most sensitive to the maximum elongation rate of main axes and their initial growth trajectory. The model will have applications in guiding the design of root system ideotypes for improved water and nutrient use efficiency and for investigating their effectiveness under a range of soil conditions and crop management regimes.     

Genetic effects and genetic relationships among <Emphasis Type="Italic">shrunken</Emphasis> (<Emphasis Type="Italic">sh2</Emphasis>) sweet corn lines and F1 hybrids

The objectives of this study were to quantify the components of genetic variance and the genetic effects, and to examine the genetic relationship of inbred lines extracted from various shrunken2 (sh2) breeding populations. Ten diverse inbred lines developed from sh2 genetic background, were crossed in half diallel. Parents and their F1 hybrids were evaluated at three environments. The parents were genotyped using 20 polymorphic simple sequence repeats (SSR). Agronomic and quality traits were analysed by a mixed linear model according to additive-dominance genetic model. Genetic effects were estimated using an adjusted unbiased prediction method. Additive variance was more important than dominance variance in the expression of traits related to ear aspects (husk ratio and percentage of ear filled) and eating quality (flavour and total soluble solids). For agronomic traits, however, dominance variance was more important than additive variance. The additive genetic correlation between flavour and tenderness was strong (r = 0.84, P < 0.01). Flavour, tenderness and kernel colour additive genetic effects were not correlated with yield related traits. Genetic distance (GD), estimated from SSR profiles on the basis of Jaccard’s similarity coefficient varied from 0.10 to 0.77 with an average of 0.56. Cluster analysis classified parents according to their pedigree relationships. In most studied traits, F1 performance was not associated with GD.