利用SRAP标记分析玉米遗传多样性

相关序列扩增多态性(SRAP)是一种基于PCR的新型分子标记技术.本研究的目的在于探讨利用该标记进行玉米种质资源遗传多样性分析和杂种优势群划分的价值及可行性.利用22对SRAP引物对16个玉米自交系进行了遗传多样性分析,共扩增出197条具多态性的条带,平均多态性信息量为0.8847,平均多态性比率为59.8%.通过聚类分析将16个自交系分为5个群,其划分结果与系谱分析基本一致.该结果表明SRAP标记是一种适合于玉米种质遗传多样性研究的分子标记.     

四川地方玉米种质的SSR聚类分析

利用SSR分子标记方法研究28个玉米自交系的遗传变异。分析四川地方玉米种质的遗传基础,并进行SSR聚类分析,探讨四川地方玉米种质与国内主要杂种优势群的关系。结果表明：大部分四川地方玉米种质均可被划分到常见的几大杂种优势群中去,少数地方玉米自交系可形成单独的类群,四川地方玉米种质具有广泛的遗传基础;SSRs能较真     

Cluster analysis of RFLP data from related maize inbred lines of the BSSS and LSC heterotic groups and comparison with pedigree data

Summary In this study, 31 elite inbred lines of maize (Zea mays L.) were analyzed with 149 clone-enzyme combinations for their respective RFLP profiles. Objectives were (1) to determine the utility of RFLPs for estimation of genetic similarties among 16 inbred lines from the Iowa Stiff Stalk Synthetic (BSSS) and among 15 inbred lines from the Lancaster Sure Crop (LSC) heterotic groups and (2) to compare genetic similarities based on molecular markers with those based on pedigree information. Coefficients of genetic similarity (GS) and coancestry (f) between pairs of lines from the same heterotic group were calculated from RFLP and pedigree data, respectively. For lines from the BSSS heterotic group, cluster analyses based on RFLP and pedigree data revealed similar associations. GS and f values were closely correlated (r=0.70) for related BSSS lines. For lines from the LSC heterotic group, considerable discrepancies existed between the GS and f values, especially for those pairs involving inbreds Va22 and Lo924. Effect of selection and/or erroneous pedigree records are discussed as possible explanations for the low correlation of GS and f values (r=0.07) for related LSC lines. RFLPs seem useful for investigation of relationships among maize inbreds, verification of pedigree records, and quantification of the degree of relatedness.     

根据SSR标记划分优质蛋白玉米自交系的杂种优势群

利用SSR标记技术对18个优质蛋白玉米(QPM)自交系和4个代表国内主要杂种优势群的普通玉米标准测验种进行杂种优势群划分, 研究热带、亚热带QPM与温带玉米自交系之间的遗传关系. 从70对引物中筛选出39对扩增谱带清晰且具有多态性的SSR引物, 在供试材料中检测到134个等位基因变异, 平均多态性信息量为0.55. 根据扩增谱带建立0、     

四川省常用玉米自交系SSR遗传多样性分析

利用SSR标记研究了33个玉米自交系的遗传变异,初步进行了杂种优势群划分,从85对SSR引物中筛选出72对扩增产物具有稳定多态性的引物。72对引物在供试材料中共检测出289个等位基因变异,每对引物检测等位基因2～7个,平均4．01个,每个位点的多态性信息量(PIC)变化于0．277～0．792之间,平均为0．599。33个自交系之间的遗传相似系数变化范围为0．5866—0．9247,平均为0．7056。UPGMA聚类分析结果表明,33个供试自交系划分为4大类,其中第1类又分为6个亚类,分类结果与系谱来源基本一致,而且类间平均遗传相似系数均小于类内平均遗传相似系数,表明分类是合理的;同时生产上主要推广杂交种的亲本大多来自不同的大类或亚类;研究表明SSR标记可以进行玉米自交系遗传多样性分析,并用于杂种优势群的划分。本研究还筛选出14对不仅带型稳定、重复性好,而且PIC值较高的引物组成核心引物,可以对供试材料进行初步分析,并认为选用大约50对以上扩增产物稳定、多态性高的引物,对供试材料进行分析就可获得较可靠的划类结果。     

玉米自交系杂种优势类群与杂优模式构建的初步研究

以１５个来源不同的玉米自交系及其１０５个双列杂交组合为材料,通过ＲＡＰＤ分析技术及试验材料的多点田间鉴定,初步研究了玉米自交系杂种优势类群的划分和利用模式的构建。根据ＲＡＰＤ分类与杂种优势分类,系谱追踪的比较研究。认为ＲＡＰＤ技术在玉米自交系杂种优势群划分上应用是可行的。通过对杂优类群间Ｆ１产量,杂种优势与配合力的测定结果的综合分析,提出了７个杂种优势利用模式。     

利用DNA指纹技术进行玉米自交系类群划分新方法——遗传背景分析法

对52个待测玉米自交系和15个对照自交系进行DNA指纹分析，计算待测玉米自交系与各类群对照自交系之间的遗传距离，不用聚类分析方法，直接根据遗传距离进行类群划分，结果表明，与传统的聚类分析方法相比，遗传背景分析方法是十分有效的玉米自交系类群划分新方法，将52个玉米自交系主要分为5大类群，即瑞德群，黄改群，P群，旅大红骨群和兰卡斯特群，未发现新的优势类群，除了自交系黄C以外，其他所有玉米自交系的类群划分结果与系谱来源相吻合，并指出黄C属于瑞德群。     

Combining ability, heterotic patterns and genetic diversity of extra-early yellow inbreds under contrasting environments

Information on the combining ability, heterotic patterns and genetic diversity of maize (Zea mays L.) inbreds is crucial for the success of a hybrid program targeting the stress environments of West Africa (WA). Studies were conducted in 2011 at four locations in Nigeria to (i) determine the combining ability of 20 extra-early yellow inbred lines, (ii) classify the inbred lines into heterotic groups, and (iii) determine the genetic diversity among the lines. General combining ability (GCA) effects were greater than specific combining ability (SCA) effects across test environments suggesting that additive gene action was more important than the nonadditive in the set of inbred lines. The lines were classified into four heterotic groups based on SCA effects, and three groups based on heterotic groups’ specific and GCA, the GCA effects of multiple traits of inbred lines and molecular markers. TZEEI 79, TZEEI 67, and TZEEI 81 were the best inbred testers while TZEEI 95 × TZEEI 79 was the best single-cross tester. TZEEI 88 × TZEEI 66 and TZEEI 96 × TZEEI 73 were identified as ideal hybrids for further testing, promotion for adoption and commercialization in WA.     

Identifying heterotic groups and testers for hybrid development in early maturing yellow maize (Zea mays) for sub-Saharan Africa

Identification of heterotic groups and efficient testers, which are important prerequisites for the development of outstanding hybrids, has been a major challenge to its success, especially for early and extra-early germplasm. This study was carried out to (a) identify the most efficient heterotic grouping method for classifying a set of inbred lines and (b) determine the efficiency of testers in classifying inbred lines into heterotic groups. A total of 205 hybrids obtained by crossing 41 inbred lines with five standard testers were evaluated together with five hybrid checks under drought, low soil nitrogen (N), Striga-infested and optimal environments in Nigeria between 2014 and 2016. The heterotic group's specific and general combining ability (HSGCA) method was more effective in classifying the inbred lines into heterotic groups. Testers TZEI 17 and TZEI 23 were the most efficient across environments and could be invaluable for classifying other lines into heterotic groups and assessing combining ability of maize inbreds. In addition, these testers and heterotic groups represent an invaluable resource for development of outstanding hybrids in sub-Saharan Africa (SSA).     

基于SSR分子标记的玉米自交系遗传多样性分析

了解新选育自交系遗传背景,确定其所属的杂种优势群,是组配杂交组合,选育新的杂交种的关键措施。此研究利用SSR标记技术分析了46份玉米自交系的遗传多样性,结果表明：12对稳定的SSR引物共检测出45个等位基因变异,每个SSR的多态性信息量（PIC）的变幅为0.31~0.76,平均为0.57,显示了较高的多态性。聚类分析显示46个玉米自交系可划分为5个类群,每一类群内所包含的自交系与系谱分析的结果基本一致。研究结果还表明,快捷、准确鉴定种质资源亲缘关系的SSR分子标记技术可以广泛应用于育种实践,提高玉米优势组合选配的效率。     

SSR荧光检测解析224份山西玉米自交系的遗传结构与遗传关系

为利用杂种优势,对玉米自交系的遗传结构及遗传关系进行解析非常必要.本研究基于40个SSR位点的分析,对山西224份玉米自交系的遗传结构与遗传关系进行了解析.共检测出171个等位变异,平均每个位点4.28个;平均每个位点多态性信息量PIC、标记索引指数、基因多样性指数分别为0.44、2.02和0.50;有9份种质存在特异...     

基于高通量测序开发玉米高效KASP分子标记

SNP (Single Nucleotide Polymorphism)在基因组中数量多、分布广,适用于大规模、自动化基因型检测。本研究利用205份不同来源的玉米自交系全基因组重测序数据鉴定出一系列多态性高的二态性SNP位点并开发出700个KASP分子标记。其中, 202个在46个玉米代表系中得到验证的KASP标记进一步用于系统进化树构建及群体结构分析。结果显示,开发成功的KASP标记在染色体上分布均匀,平均PIC为0.463,平均MAF为0.451。基于KASP标记位点和总SNP位点的聚类分析结果高度吻合。KASP标记位点与总SNP位点的遗传距离相似性系数高达89.5%,能成功区分玉米的杂种优势群。该KASP标记可在玉米种质资源分析、连锁群构建以及杂种优势群划分等方面发挥重要作用。     

Assessment of heterotic patterns of tropical low-nitrogen–tolerant maize (Zea mays L.) inbred lines using testcross performance,morphological traits and SNP markers

Breeding efforts in West and Central Africa (WCA) have focused on the development of Low-N-tolerant (LNT) maize inbreds and their classification into heterotic groups. This study was conducted to classify LNT maize lines into heterotic groups using testcross performance, morphological and SNP markers and to compare the consistency of groupings by the three methods. Thirty-six LNT inbreds were crossed to two contrasting inbred testers to generate 72 testcrosses that were evaluated under low-N conditions in Nigeria in 2014. Also, the 36 inbreds and the two testers were evaluated for per se performance under similar conditions as the testcrosses in 2014 and genotyped in 2015 using 1,123,196 SNP markers. Based on testcross performance, 33 of the 36 LNT inbreds were grouped by the two testers. Morphological characterization from per se performance and genetic relationship by SNP markers classified the inbreds into four groups that were inconsistent with their pedigree. Correlation analysis showed non-concurrence of the three grouping methods. However, information from these groupings would assist in reducing the number of crosses to be made and evaluated.     

利用RFLP和SSR标记划分玉米自交系杂种优势群的研究

利用RFLP和SSR标记对29个玉米自交系进行杂种优势群划分,筛选出56个多态性RFLP探针酶组合,66对多态性SSR引物,分别在供试材料中检测到187个和232个等位基因变异。两种方法比较表明,SSR标记的平均多态性信息量(PIC,0.54)高于RFLP(0.42);但对供试材料的遗传多样性评价基本一致,平均遗传相似系数(GS)分别为0.64和0.62。综     

我国部分玉米自交系遗传关系和遗传结构解析

玉米自交系遗传关系和遗传结构的解析,对自交系类群划分和杂交组配具有重要的指导意义。本文选用玉米基因组的112个SSR标记对我国97个玉米自交系进行遗传关系和遗传结构分析,并评价了遗传距离聚类和模型聚类方法在玉米自交系遗传关系研究中的应用价值。结果表明,模型聚类方法更适于玉米自交系的遗传关系研究。解析自交系的遗传基础发现,各类群中均有大量自交系含有其他类群的遗传成分。根据模型聚类结果,97个自交系被划分为PB、Reid、塘四平头和旅大红骨4个类群。Reid群与旅大红骨群的遗传关系最近,与塘四平头群遗传关系最远。为了实现杂种优势模式的简化,4个类群可被简化为3大种质类群[A(旅大红骨群与Reid群)、B(PB群)、C(塘四平头群)],或2大种质类群[A(旅大红骨群、Reid群、PB群)、B(塘四平头群)]。研究结果为自交系的改良和利用及杂种优势模式确定提供了理论基础。     

Assessing the genetic diversity of Portuguese maize germplasm using microsatellite markers

A collection of Portuguese maize accessions representing a valuable source of genes for introduction into modern cultivars is stored at the Portuguese Plant Germplasm Bank (Banco Português de Germoplasma Vegetal—BPGV). To assess genetic diversity among inbreds, microsatellite analysis was carried out for 54 inbred lines representing the diversity of Portuguese dent and flint maize germplasm. Fifty American and other European elite inbreds were also analysed for comparison. Fifteen microsatellite loci distributed throughout the maize genome were chosen based on their repeat unit and base composition. A total of 80 alleles were detected with an average allele number of 5.33 per locus. Polymorphism information content (PIC) values and observed genetic distances showed the existence of large variability among inbreds. Cluster analysis indicated that almost all of the inbreds could be distinguished from each other and Portuguese inbreds were present in all clusters formed. These associations were consistent with the known pedigree records of the inbreds, confirming a mixed origin of Portuguese materials. Comparative analysis of microsatellite diversity among groups was established according to important traits for both breeding and line identification. This revealed that, although most of the genetic diversity (>95%) was attributable to differences among inbreds of different groups, the existence of phenotypic differentiation in endosperm colour, kernel type and cob colour could be suggested for grouping. These findings support the joint use of molecular and morphological traits in management of the germplasm collection. In this study, SSR markers proved to be effective to characterise and identify maize inbred lines, and demonstrate associations among them. This revised version was published online in July 2006 with corrections to the Cover Date.     

Combining ability amongst CIMMYT’s early maturing maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) germplasm under stress and non-stress conditions and identification of testers

CIMMYT (International Maize and Wheat Research Institute) Zimbabwe’s early maturing maize program, which aims to supply seed to approximately 4 million hectares of maize area in eastern and southern Africa, lacks adequate information on heterotic relationships among early maturing germplasm and has no early maturing testers for hybrid development. Open-pollinated varieties (OPVs) and hybrids are the products targeted for this region. Among the hybrids, three-way and double-cross hybrids are desired. Thus the use of single crosses as testers would be an appropriate choice for such a breeding program as one could potentially identify three-way combinations during the early generation test. A twelve-parent diallel was formed and crosses evaluated to identify heterotic groups and single-cross testers. Crosses were evaluated under four different environments in Zimbabwe, two optimal, one low nitrogen stress and one drought stress. P5 (an early maturing line from heterotic group A) and CML 395 (a late maturing inbred line from heterotic group B) were used as reference parents to establish heterotic groupings of germplasm used in the diallel. The single cross (P7/P8) was identified as a potential group A tester because of: (a) co-classification of inbred lines into heterotic group A, (b) good yields-9.8 t/ha (optimal), 3.4 t/ha (low nitrogen) and 2.1 t/ha (drought); and (c) good GCA effects for grain yield (0.49 t/ha) of line P7 while line P8 contributed to reduced height and anthesis-silking interval.     

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.     

糯玉米自交系SSR标记遗传多样性及群体遗传结构分析

为了解糯玉米种质的遗传基础,利用29对SSR标记对87份糯玉米自交系进行遗传多样性分析,共检测出180个等位变异,平均每个位点6个等位变异,多态性信息含量变幅为0.308～0.915,平均为0.572。材料间遗传相似系数为0.49～0.93,平均为0.66。通过聚类分析UPGMA (unweighted pair-group method with arithmetic means)方法在遗传相似系数0.64处将87份糯玉米自交系划分为4个类群,分别包含9、66、10和2份材料。此外,利用Structure群体遗传结构分析也将87份糯玉米自交系分为4个类群,分别包含24、25、19和19份材料;进一步分析表明,供试群体中大部分糯玉米自交系的遗传变异较单一。本研究为糯玉米新品种选育和遗传进化分析提供了种质基础和理论依据。     

Genetic diversity in tropical maize inbred lines: heterotic group assignment and hybrid performance determined by RFLP markers

Tropical maize inbred lines, eight derived from a Thai synthetic population (BR‐105) and 10 from a Brazilian composite population (BR‐106), were assayed for restriction fragment length polymorphisms with 185 clone‐enzyme combinations. The aim of this study was to investigate genetic distances among tropical maize material and their relationship to heterotic group allocation and hybrid performance. Genetic distances (GDs) were on average greater for BR‐105×BR‐106 lines (0.77) than for BR‐106×BR‐106 (0.71) and for BR‐105×BR‐105 (0.69) lines. Cluster analysis resulted in a clear separation of BR‐105 and BR‐106 populations and was according to pedigree information. Correlations of parental GDs with single crosses and their heterosis for grain yield were high for line crosses from the same heterotic group and low for line combinations from different heterotic groups. Our results suggest that RFLP‐based GDs are efficient and reliable to assess and allocate genotypes from tropical maize populations into heterotic groups. However, RFLP‐based GDs are not suitable for predicting the performance of line crosses from genetically different heterotic groups.