19个广西审定丝苗型品种主要农艺性状与遗传多样性聚类分析

为了明确广西审定丝苗型品种的趋同程度与遗传差异,选用19个广西审定丝苗品种,通过18个主要农艺性状表型鉴定与聚类分析,并采用48对SSR标记进行遗传多样性分析。结果表明：基于农艺性状表型的品种间欧氏距离聚类,可分为4类,包含12个品种的类群农艺性状表型表现趋同;3个两系品种,2个常规稻,14个三系品种均被聚类在不同的大类中,说明育种方式不影响表型聚类,农艺性状表型差异多样。基于SSR标记的遗传距离聚类,所有品种可以被划分为4个类群,而不同类群之间的遗传差异也显而易见,遗传多样性丰富;具有相同母本,或采用相同父本的品种,基本归于同类。两种聚类结果的对比表明,育种中品种间会出现遗传关系较远,农艺性状接近的情况;也会出现遗传关系较近,农艺性状相差较远的情况。研究农艺性状表型鉴定与聚类和解析遗传多样性的结果可为广西丝苗型品种的选育和推广保护提供理论和技术支持。     

距离分析方法在小麦亲本选配中的应用研究

作者对距离分析方法在小麦亲本选配中的应用问题做了系统研究,本文是这一研究的总结报告。结果表明:1.遗传距离与杂种优势的关系受试验材料的影响。从聚类结果来看,在小麦育种中选择类间亲本进行杂交要优于类内亲本间的杂交。2.就性状选用方法而言,广义遗传力法要优于常规法和权重法。3.距离分析所反映的遗传差异不同于亲缘差     

不同密度下小麦新品系主要性状的综合分析

本研究旨在使小麦新品系快速的应用于农业生产,探讨不同的统计分析方法,以4种密度4个小麦新品系(种)的主要性状为指标,运用聚类分析以及TOPSIS法对其新品系进行综合分析。采用TOPSIS法对两个品系在不同的种植密度下的12个主要性状进行综合评价,其评判结果为:品系223综合性状最好,2138品系较差;品系223选择150万株hm2,品系2138选择240万株hm2。聚类结果分为三类:第一类是不同密度下品系2138的两个高密度下处理和对照品种,第二类是品系223在四种不同密度下的结果,第三类是品系2138在种植密度为150万株hm2和240万株hm2的结果。采用聚类分析和TOPSIS法相结合的分析方法,综合评判了不同种植密度下小麦新品系优劣,两者的综合评判的总趋势基本一致,用这两种方法结合评价新品系以及合适的栽培密度各有优势。     

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.     

苎麻核心种质构建方法

选用国家长沙苎麻圃的790份种质资源,在已有的25个性状数据的基础上,采用不同取样方法、不同系统聚类方法、不同遗传距离方法构建苎麻核心种质,用质量性状的多样性指数均值、表型保留比率均值和数量性状均值差异百分率、方差差异百分率、极差符合率和变异系数变化率等6个指标评价不同方法组合(取样方法、聚类方法、遗传距离)构建核心种质的优劣。选出合适的构建方法,构建苎麻核心种质。结果表明,不同的取样方法对质量性状和数量性状的遗传多样性影响不同,就质量性状的最大遗传多样性而言,选择优先取样+多次聚类随机取样方法比较适宜,而对数量性状的最大遗传多样性而言,选择优先取样+多次聚类变异度取样方法则较适宜。用优先取样+多次聚类随机取样方法取样时,采用最短距离法和重心法构建的核心种质最好,用优先取样+多次聚类变异度取样时,采用离差平方和法则是构建苎麻核心种质的最佳聚类方法。苎麻核心种质构建与质量性状的不同遗传距离无关,但数量性状以欧氏距离最佳。     

陆地棉品种与性状遗传差异的对应分析

本文通过3年的试验资料,运用对应分析的方法对40个陆地棉品种的10个主要产量和品质性状进行了研究,并利用因子距离探讨了品种与性状的分类及遗传差异与10个杂交组合 F_2代性状变异的关系。结果表明:对应分析能有效地同时揭示性状间、品种间及性状与品种间的关系,两年聚类结果品种符合率达77.5%,因子距离的大小与品种地理来源     

春小麦SSR标记与农艺性状、品质性状聚类结果的关联分析

以84份春小麦为材料,对SSR标记聚类结果和农艺性状、品质性状的聚类结果进行了关联分析,结果表明:SSR标记聚类与农艺性状聚类的对应关系主要表现在大类之间,各亚类之间无明显对应关系;与品质性状聚类间存在一定的对应关系,但这种对应关系并不明显。类间种质吻合率分析也表明,SSR标记聚类与农艺性状、品质性状聚类结果间的吻合率较低,最高上限分别为55.74%、54.55%,因此,在实际中应将不同的标记综合起来进行分析,以提高检测结果的准确性和可靠性。     

聚类分析在大豆“3414”试验设计中的应用

为了探讨大豆在"3414"试验设计下各个性状的关系以及对产量的影响,采用系统聚类的R型聚类法对‘安豆7号’在"3414"试验设计下的9个农艺性进行研究,采用中位数聚类法计算9个性状间的相关系数。结果表明:9个性状共划分为4个类,Ⅰ类为单株有效荚数、单株粒数、单株粒重、百粒重和产量,Ⅱ类为株高和主茎节数,Ⅲ类为有效分枝,Ⅳ类为底荚高度。剔除基因型对变量聚类的影响,明确了类间的典型指标,可为大豆品种的选育及性状相关研究提供参考。     

谷子顶三叶与主要农艺性状的相关性分析

为了明确谷子从早期品系到育成品种过程中顶三叶和其他农艺性状的变化规律,本研究利用41份育种品种和30份早期品系,在60万株/hm2种植密度下,分析育成品种和早期品系顶三叶性状的差异,以及与其他农艺性状的关系.结果 表明,育成品种顶三叶长度、宽度和面积总体上高于早期品系,而变异幅度低于早期品系;育成品种项三叶性状之间的相关性明显高于早期品系,而顶三叶与穗部性状之间的相关性低于早期品系;育成品种产量与顶三叶大小显著负相关,这种负相关关系主要存在于叶片较大的品种中,而在叶片较小的品种中并不存在.本研究结果为谷子品种选育中对顶三叶性状的选择提供参考.     

19个玉米自交系的数量性状和AFLPs的遗传差异比较研究

以3个新近选育和16个生产上常用骨干系总计19个玉米自交系为材料，比较它们在数量性状和AFLPs上的遗传差异。结果表明，表型数量性状与AFLPs数据的两种聚类结果都与自交系系谱有较好的一致性，且AFLP的吻合程度较高，两种聚类结果都一致把19个自交系所组配的生产推广优势组合的双亲分在不同的组或亚组；其中新选系中的21-ES、A318与其他骨干系在数量性状与AFLPs上有较大差异，被单独聚为一类；各自交系间的数量性状和AFLPs的遗传距离与其F1的中亲优势值呈正相关。     

Heterotic patterns in rapeseed (Brassica napus L.): II. Crosses between European winter and Chinese semi-winter lines

Chinese semi-winter rapeseed is genetically diverse from European winter rapeseed. Our objectives were (1) to evaluate the potential of semi-winter rapeseed for winter rapeseed hybrid breeding, (2) to assess the relative importance of general combining ability (GCA) vs. specific combining ability (SCA) among combinations between Chinese semi-winter and European winter rapeseed, and (3) to compare the strategies to predict heterosis based on parental genetic distance (GD) estimated from AFLP marker data and GCA for hybrid performance. Four winter male sterile lines from Germany as testers were crossed with 14 Chinese semi-winter rapeseed lines to develop 56 hybrids, which were evaluated together with their parents and commercial hybrids for seed yield, oil content and protein content under three environments in Germany. The Chinese parental lines were not adapted to local environmental conditions as demonstrated by lacking winter hardiness and poor seed yields per se . However, the hybrids between the Chinese parents and the adapted winter rapeseed lines exhibited high heterosis for seed yield. About 20% of the hybrids were significantly superior to the respective hybrid control under three environments. Additive gene effects mainly contributed to hybrid performance since the variance components of GCA were higher as compared with SCA. The correlation between parental GD and hybrid performance was found to be low whereas the correlation between GCA and hybrid performance was high and significant, with correlation coefficients of 0.95 for seed yield, 0.87 for oil content, and 0.91 for protein content, indicating that GCA can predict hybrid performance. These results demonstrate that Chinese semi-winter rapeseed germplasm has a great potential to increase seed yield in winter rapeseed hybrid breeding programmes in Europe.     

Selection environment and environmental sensitivity in barley

Summary Groups of 10 barley genotypes were selected for high grain yield under either high yielding (two groups) or low yielding conditions (two groups). The genotypes had a similar average grain yield across a wide range of yielding conditions, but differed in their linear response over environments (environmental sensitivity). The genotypes selected for high grain yield under low yielding conditions were less sensitive to changing environments than genotypes selected for high grain yield under high yielding conditions. The higher stability of genotypes selected under low yielding conditions was shown by both the linear regression analysis and the comparison of coefficients of variation. The use of a safety-first index showed that the probability of a crop failure of genotypes selected for high grain yield under high yielding conditions was between 1.8 and 2.7 times higher than for genotypes selected for high grain yield under low yielding conditions. The development of new cultivars for areas where a large proportion of the crop is grown by subsistence farmers should therefore be based on selection under low yielding conditions.     

3个大豆品种及其骨干亲本的亲缘关系和指纹图谱分析

为了研究江苏淮北地区大豆推广品种及其骨干亲本的亲缘关系和指纹图谱,以3个淮豆系列品种及其8份骨干亲本品种为试验材料,利用CTAB法提取基因组DNA,采用SSR分子标记对11份大豆品种进行亲缘关系和指纹图谱分析。结果显示：利用筛选出的46对SSR引物在11个大豆品种中共检测出125个等位变异,每对引物可检测到2~5个等位变异。使用非加权类平均法进行聚类分析,大部分供试材料间的遗传变异较小,遗传相似系数为0.5781~0.9609。SSR标记遗传距离为0.0391~0.4219,平均0.2773。从上述引物中选取5个核心引物构建的指纹图谱能够鉴别3个淮豆系列品种。上述结果不仅用于品种鉴定及其知识产权保护,还为有效选配亲本拓宽遗传基础提供了理论基础和技术支持。     

Genetic diversity of Tainan-white maize inbred lines and prediction of single cross hybrid performance using RAPD markers

To evaluate the genetic diversity of 13 maize inbred lines, and to determine the correlation between genetic distance and single cross hybrid performance, we employed the randomly amplified polymorphic DNA(RAPD)- a PCR-based technique. Six of these lines came from the Taichung population, and others derived from seven different sites. Forty different primers were used to give a total of 646 reproducible amplification products, 547 (84.7%) of them being polymorphic. Genetic divergence was determined using Jaccard's similarity coefficient, and a final dendrogram was constructed by UPGMA (unweighted pair-group method with arithmetical averages) cluster analysis in the CLUSTER procedure of the SAS system. The RAPD analysis was a useful tool in determining the extent of genetic diversity among Tainan-white maize inbred lines in the present case. Cluster analysis showed that the 13 inbred lines could be classified into distinct heterotic groups. There was no significant linear regression of grain dry weight heterosis value and mean performance of hybrids on genetic distance. And their coefficients of determination(R²) are small, so that predictive value is limited. The present results showed that the Jaccard's similarity coefficients based on RAPD data cannot be used to precisely predict the F₁ hybrids yield performance and heterosis value. This revised version was published online in August 2006 with corrections to the Cover Date.     

Yield potential and drought tolerance of segregating populations of barley in contrasting environments

Summary Using the traditional approach (selection for grain yield) it has been found that F₃ families derived from F₂'s selected under unfavourable conditions were more vigorous in the early stages of growth, taller, earlier in heading and with larger yields than F₃ families derived from F₂'s selected under favourable conditions. A high and negative correlation coefficient was found between the drought susceptibility index and grain yield at the driest site, whereas at the wettest site the correlation coefficients were lower and in some cases positive, indicating the existence of traits which are desirable under drought and undesirable under favourable conditions, or vice versa.Expected responses to selection for grain yield using different selection criteria indicated that selection under stress conditions is expected to be more efficient than selection under favourable conditions when dry areas is the target environment.Expected responses to selection for grain yield using different selection criteria indicated that selection under stress conditions is expected to be more efficient than selection under favourable conditions when dry areas is the target environment.Part of this work was supported by Opec Fund for International Development.     

Comparison of phenotypic and molecular marker-based classifications of hard red winter wheat cultivars

Genetic diversity is the basis for successful crop improvement and can be estimated by different methods. The objectives of this study were to estimate the genetic diversity of 30 ancestral to modern hard red winter wheat (Triticum aestivum L.) cultivars adapted to the Northern Great Plains using pedigree information, morphological traits (agronomic measurements from six environments), end-use quality traits (micro-quality assays on 50 g grain or milled flour samples for the six environments), and molecular markers (seed storage proteins separated using SDS-PAGE, 51 SSRs, and 23 SRAP DNA markers), and to determine the relationships of genetic distance estimates obtained from these methods. Relationships among diversity estimates were determined using simple (Pearson) and rank (Spearman) correlation coefficients between distance estimates and by clustering cultivars using genetic-distances for different traits. All methods found a wide range in genetic diversity. The genetic distance estimates based on pedigree had the highest values due to possible over-estimation arising from model assumptions. The genetic diversity estimates based on seed storage protein were lowest because they were the major determinants of end-use quality, which is a highly selected trait. In general, the diversity estimates from each of the methods were positively correlated at a low level with the exceptions of SRAP diversity estimates being independent of morphologic traits (simple correlation), SDS-PAGE, and SSR diversity estimates (rank correlation). However, SSR markers, thought to be among the most efficient markers for estimating genetic diversity, were most highly correlated with seed storage proteins. The procedures used to accurately estimate genetic diversity will depend largely upon the tools available to the researcher and their application to the breeding scheme.     

陆地棉遗传距离与纤维品质性状中亲优势及F1、F2表现的相关性研究

通过29个陆地棉品种(系)表型性状及SSR标记遗传距离聚类分析,依据遗传距离大小在不同类群中选择了8个遗传背景差异不同的陆地棉亲本,进行不完全双列杂交,共配制了28个组合,开展了陆地棉纤维品质性状F1、F2表现及其中亲优势与遗传距离之间的相关、回归分析研究.结果发现杂种F1、F2纤维上半部平均长度、整齐度指数、断裂比强度及其中亲优势均与表型及SSR标记遗传距离正相关,其中杂种F1纤维上半部平均长度与2种遗传距离均达到了显著水平,断裂比强度与SSR标记遗传距离达显著水平;伸长率的杂种F1、F2表现及其中亲优势均与表型及SSR标记遗传距离负相关,其中杂种F1伸长率与SSR标记遗传距离显著负相关.回归分析发现与遗传距离达到显著或极显著相关的纤维品质性状,均与对应遗传距离具有显著或极显著拟合的曲线模型.这些显著或极显著的纤维品质性状,可在育种实践中为利用杂种优势改良棉纤维品质提供参考信息.     

棉花杂交亲本距离估测与聚类分析方法的探讨

本研究利用四十个陆地棉亲本,经两年异地试验证明,以表型相关(r_p)矩阵代替遗传相关矩阵(r_g)作为距离分析的基础转换矩阵,不仅从统计角度分析是可行的;而且从应用角度分析,前者也具有相关结果一致性好,性状标准化合理,相关矩阵不会出现不正定性,年份之间可保证参与距离分析的性状完全一致,D~2估测结果一致性及聚类分析结果相符率高等优点.最长距离法的聚类范围大,并类合理且灵敏度高,聚类结果实用价值高,建议以表型相关矩阵(P)—主成份转换(C)—欧氏距离(E)—最长距离法(L).即PCEL法,作为棉花杂交亲本距离估测与聚类分析的适宜方法.     

张掖日光温室最低温度预报模型的主成分回归法构建

为了有效预报日光温室内部最低温度,减弱低温冷害对设施农业生产的影响。利用张掖日光温室内小气候数据及室外气象观测资料,选取8个影响日光温室最低温度的气象因子进行相关分析和统计检验的多重共线性诊断,应用主成分回归方法建立日光温室最低温度预报模型,并用模型模拟值与温室最低温度实测值比较对模型精度进行检验。结果表明：气象因子X₁、X₂、X₄、X₆、X₇、X₈间存在共线性的问题。通过主成分分析综合提取了3个主成分代替原来的8个变量,建立的温室最低温度预报模型通过α=0.01水平显著性检验,且模型精度检验表明,不同天气条件（晴天、少云—多云、阴天）的模拟值和实测值间R²在0.81~0.89之间,RMSE在0.90~1.16℃之间;不同时段（12月—次年2月）的模拟值和实测值间R²在0.82~0.89之间,RMSE在0.94~1.13℃之间。