中国南瓜自交系的聚类分析(英文)

A cluster analysis was carried out based on Euclidean genetic distances through UPGMA method in Chinese pumpkin inbred lines.7 important agronomic traits of 46 Chinese pumpkin inbred lines were investigated.The result indicated that 46 pumpkin inbred lines were clustered into 4 groups and the inter-groups distances was larger than that in intra-group.The genetic distances of parents were related to F1 performance and the results of cluster would increase effectiveness in the Chinese pumpkin crossing breeding.     

Cluster Analysis of Chinese Pumpkin Inbred Lines

A cluster analysis was carried out based on Euclidean genetic distances through UPGMA method in Chinese pumpkin inbred lines.7 important agronomic traits of 46 Chinese pumpkin inbred lines were investigated.The result indicated that 46 pumpkin inbred lines were clustered into 4 groups and the inter-groups distances was larger than that in intra-group.The genetic distances of parents were related to F1 performance and the results of cluster would increase effectiveness in the Chinese pumpkin crossing breeding.     

Genetic Relation Analysis on Ramie [Boehmeria nivea （L.） Gaud.] Inbred Lines by SRAP Markers

The objective of this article is to reveal the variations of ramie inbred lines in DNA level and discuss their molecular background to provide a theoretical basis for ramie cross breeding. In the present study, the genetic relationships among 33 inbred line accessions and two wild types that originated from China and Brazil were estimated using sequence-related amplified polymorphism （SRAP） markers. The results showed that 33 out of 81 primer combinations turned out to be polymorphic and 332 polymorphism bands were obtained. On the basis of the appearance of the markers, the genetic relationships were analyzed using unweighted pair-group method of arithmetic average cluster analysis （UPGMA）, and the genetic Jaccard similarity coefficients were calculated. The inbred-lines originating from China and Brazil formed a cluster suggesting a possibility that the Brazilian cultivars could have developed from cultivars introduced from China. Within ramie inbred-lines, the groupings also indicated that the greatest genetic relationship among cultivars was correlated to the region of origin of cultivars. The results provided the evidence that SRAP was an efficient approach, suitable for taxonomic analysis of ramie inbred lines, To the authors＇ knowledge, this is the first application of SRAP marker on the systematics of ramie inbred lines.     

Determination of the Number of SSR Alleles Necessary for the Analysis of Genetic Relationships Between Maize Inbred Lines

The amount of molecular marker information has considerable impact on the results of studies of crop germplasm genetic relationships in crop. The number of alleles required to reveal genetic relationship in maize inbred lines is a theoretical issue that needs to be addressed. In this study, 112 pairs of SSR （simple sequence repeat） primers and 97 maize inbred lines were selected to study the relationship between the number of inbred lines and the number of SSR primers and alleles required for a stable cluster. The results showed that the number of SSR primers is not tightly associated with the stability of the cluster analysis results, while an increase in the number of alleles can significantly improve the stability of cluster analysis results. The number of inbred lines （X） is significantly associated with the number of alleles required for stable cluster analysis （Y）, and the regression equation is Y- 600.8xe（-15.9/x）. This equation can be used to calculate the number of SSR alleles required for a genetic relationship study of maize inbred lines. These results provide a reference for determining of SSR alleles number in genetic relationship analysis of maize inbred line and other crop germplasm.     

Genetic Structure of Native Sheep Populations in East and South Asia

Variations of structural loci among 4 sheep populations in China were examined by the method of multiloci electrophoresis, and similar data from 11 sheep populations were taken as basic references to analyze the genetic structure of the native sheep populations in East and South Asia. The results showed that the average heterozygosity and effective number of alleles among 15 populations were 0.2746 and 1.559, respectively. Mongolian sheep possessed the largest average heterozygosity and effective number of alleles. Genetic diversity of sheep populations in Mongolia, China, Vietnam, Bangladesh and Nepal was reduced in this order. The coefficients of genetic differentiation were between 0.0126 and 0.3083, with the average of 0.148, demonstrating that genetic variations lay mainly in populations with 85.2% of the total variations. There exists no correlation between geographical distances and genetic distances. Gene flow was smooth among most populations, which led to inconsistency between geographical distances and genetic distances. The 15 native sheep populations in East and South Asia could be divided into two groups： One group included part populations of China and Mongolia, and the other included Yunnan populations of China, and part populations of Nepal and Bangladesh. Other populations did not cluster together and divide into the above-mentioned two groups. Tills study indicated genetic differentiation of the 15 native sheep populations in East and South Asia was relatively low, geographical isolation was not the main reason affecting genetic differentiation, and the fifteen sheep populations could be divided into two groups according to phylogenetic relationships.     

Genetic Diversity of Recurrent Selection Populations with Ms2 Gene Assessed by Gliadins in Common Wheat （Triticum aestivum L.）

The male-sterile lines with Ms2 gene were highly evaluated in recurrent selection in wheat （Triticum aestivum L.）. Three populations C6 （population after six cycles of selection）, C7 （population after seven cycles of selection）, and C8 （population after eight cycles of selection） were constructed through recurrent selection with 12 parental materials （P）. Acid polyacrymide gel electrophoresis （A-PAGE） analysis was used to identify gliadin patterns and evaluate the genetic diversity in 12 parents and three populations. A total of 63 bands were identified, of which 17 polymorphic bands and 7 unique bands were present in populations and seven polymorphic bands and four unique bands were present in parents. The number of polymorphic and unique bands decreased gradually from C6 to C8, especially for to- and y-gliadins. The genetic distances in C6, C7, and C8 were calculated. The distributions of genetic distance were different in three recurrent selection populations. From C6 to C8, the genetic distance was 0.2687, 0.2652 and 0.1987, respectively. Statistically significant differences were detected between C7 and C8 with the T value of 37.9718. The result of cluster analysis based on genetic similarity matrix of three populations fitted well to those of principle coordinates analysis （PCoA）. Compared with 12 parents, almost all individuals of three populations are new genotypes. Most of the individuals from C6 and C7 could be divided into two groups, while most individuals of C8 were in one cluster. In conclusion, the results indicated that the genetic diversity was decreased severely according to the information revealed by A-PAGE, although some variations could be created in the recurrent selection. It was necessary to introduce diverse germplasm based on the genetic database of recurrent population to maintain and improve the breeding efficiency in the further program.     

Studying the physiological and yield responses of sunflower inbred lines to full and limited irrigation

In order to study the physiological and yield responses of sunflower inbred lines to full and limited irrigation, an experiment was conducted in the growing season of 2014–2015 in the research field of the Agricultural Research Station in Khoi, Iran. Water withholding was imposed in the flowering stages from R4 (initial flowering) to R6 (full flowering). The results showed that the main effect of irrigation and inbred lines and the interaction effect between irrigation and inbred lines in terms of the proline and protein contents, the catalase, peroxidase, and polyphenol oxidase activities, and seed yield in all inbred lines, and relative water content(RWC) were significant at 1% level. Water withholding in the flowering stage increased the proline content and the catalase, peroxidase, and polyphenol oxidase activities, whereas limited irrigation decreased the protein content and seed yield in all inbred lines and RWC. The lowest protein content and the highest catalase, peroxidase, and polyphenol oxidase activities were observed in BGK 39 under limited irrigation condition, while BGK 37 revealed the highest proline content in such circumstances. The highest seed yield was seen in BGK 1 and BGK 375 in full irrigation condition. Limited irrigation increased the proline content by 49.51%, compared to that of full irrigation condition.     

Differential Gene Expression in Response to Drought Stress in Maize Seedling

To provide the useful information for the choice of molecular marker used in marker-assisted selection of drought tolerance, it is necessary to find out more candidate genes and fulfill the information gaps in gene expression regulation under drought stress. In this study, we isolated four differentially expressed cDNA fragments from leaves of a droughttolerant inbred line by suppression subtractive hybridization and reverse Northern hybridization, and validated their differential expression patterns among six inbred lines with different drought tolerance in response to drought stress by quantitative real-time PCR. Sequence similarity analysis indicated that two of four differentially expressed cDNA showed homology to gene DegP encoding trypsin-like serine protease, and gene PGAM-i encoding cofactor-independent phosphoglyceromutase, respectively. Expressions of the genes corresponding to four cDNA fragments was decreased at 6 h after drought stress treatment in most of the six inbred lines, and then returned to the control level with further stress in three of the tolerant inbred lines. The expression of the gene PGAM-i and the genes corresponding to fragments E4 and F4 were increased to a high level in tolerant inbred line 81565. In the two drought-sensitive inbred lines （Dan340 and ES40）, the expression of these genes was still down-regulated. The probable mechanisms of these genes in response to drought stress were discussed. These results indicated that the drought-tolerant inbred lines upregulated the expression of the drought-tolerant candidate genes, in contrast, drought-sensitive inbred lines downregulated the expression of the genes.     

A Classification of 45 Maize Inbred Lines Used in China with RFLP Markers

The classification of heterotic groups is essential to maize breeding because knowledge of heterotic groups could be interest to both the combination of outstanding hybrids and the improvement of elite inbred lines. RFLP has provided a powerful tool to assign maize inbred lines into heterotic groups. In this investigation, 45 inbred lines, used widely in south and southwest China, were chosen for RFLP analysis,among which 4 lines came from American, representing different heterotic groups in U.S. corn belt. 54 RFLP core markers covering 10 chromosomes of maize were used. A total DNA of each sample was digested with EcoR I, BamH Ⅰ and Hind Ⅲ . The procedure of RFLP was employed as described by a manual from maize RFLP lab at University of Missouri, Columbia. A total of 860 bands were detected among 45 inbred lines based on RFLP analysis, which were involved in 212 loci. Alleles at each locus ranged from 2 to 9 with an average of 4.06. In total, The 45 inbred lines were classified into 6 heterotic groups according to RFLP data with Ward‘s method. 3 heterotic groups, including Mo17, B73 and Oh43 respectively, seemed to be the same to U. S. heterotic groups. 21 inbred lines, most of which derived from Chinese local germplasm, were classified together into two heterotic groups, indicating domistic germplasm was different from U. S.germplasm at the molecular level and played an important role in maize hybrid production in China. Two inbred lines from tropic germplasm were assigned in the same group. These results provided useful information for our understanding maize heterotic groups and heterotic patterns in China.     

Study on Physiological Maturity and Natural Drydown Rate in Maize

Physiological meturity stage,kernel water content in physiological maturity and natural drydown rate of 42 maize inbred lines and 8 hybrids were studied in field test.The results showed that the late and mid-late and mid-early inbred lines and hybrids tested reached their physiological maturity stage at 50-60d and 45-50d after silking,respectively,and at this time the water content of kernel was 28%-42%and 26%-40,respectively,The drydown rate of the inbred lines and hybrids tested had significant differences and had significant correlation with ear diameter and ear position.The late line Ji16,mid-late lines Ji846 and ZaC546,the mid-early line Longkang 11 and the early line Dong91 were moisture quick-loss inbred lines and cound be used in fast drydown maize hybrid breeding program.     

中国南瓜自交系的聚类分析

为提高中国南瓜杂交育种中亲本选配的预见性,该试验以48个中国南瓜自交系为材料,以7个重要农艺性状的调查数据为基础,采用欧氏距离和UPGMA法,对其进行聚类分析。结果表明,48个南瓜自交系被聚为4类,类间距离大于类内距离,聚类结果与F1代表现相关,对南瓜杂交育种具有一定的指导意义。     

16个南瓜自交系遗传特征的初步研究

选用16个具有代表性的南瓜自交系,采用多系测交法组配了64个杂交组合,随机抽取14个杂交组合进行分析。结果表明,南瓜自交系的杂交后代普遍存在杂种优势。在这14个杂交组合中,单果重的中亲优势均为正值,其平均值为1.51;可溶性固形物的中亲优势为正值的杂交组合共10个,占整个杂交组合的71.43%,平均值为0.08。在16个南瓜自交系中,单果重一般配合力最高的是129,可溶性固形物一般配合力最高的是053。16个自交系被分成3个类群。     

中国南瓜经济性状遗传初探

对55个中国南瓜自交系及其23个F1代4个重要经济性状进行调查,分析了各性状的变异程度、性状间的相关及杂种一代的优势表现.结果表明,各性状在不同材料间差异明显,平均变异系数达35.88,反映了中国南瓜遗传资源相当丰富.单果质量与产量呈极显著正相关(r=0.5574);而可溶固形物含量与单果质量及产量呈显著负相关,相关系数分别为-0.3872和-0.3142;果形指数与单果质量、可溶固形物含量、产量相关性则无显著相关性.南瓜产量和单果质量的正向杂种优势明显,杂交育种潜力较大;而果形指数负向超优势明显,F1趋向扁盘状.     

33个糯玉米自交系遗传主成分和距离分析

对33个糯玉米自交系的数量性状进行遗传主成分分析,初步认为自交系遗传主成分与它的一般配合力有一定的联系,并初步提出评选糯玉米自交系优劣的遗传主成分标准。测定33个糯玉米自交系遗传距离共528个,最小为0.51,最大是11.5,2.1～6.0的占84.8%。根据遗传距离,将33个糯玉米自交系聚为17类,其类间距离大于类内距离。糯玉米自交系间遗传距离大小与地理差异、亲缘关系无必然联系,同一品种自交后代选育出的姊妹系间也可具有较大的遗传距离。糯玉米自交系间遗传距离与糯玉米杂种F#-1单株粒重平均优势指数之间呈显著正相关,相关系数r=0.603**。     

利用SSR标记研究爆裂玉米自交系的遗传变异及其与普通玉米的遗传关系

 利用113对多态性SSR引物研究了来源于8个基础材料的26个爆裂玉米自交系的遗传多样性及其与分属6个杂种优势类群的20个普通玉米骨干自交系的种质关系。在26个爆裂玉米自交系间共检测出301条带，平均每个位点的等位基因数为2.66个，多态性信息量为0.068～0.217，平均遗传距离为0.357。利用SSR数据进行聚类分析，将46个供试自交系分为爆裂和普通玉米自交系两大类；26个爆裂玉米自交系分为8个类群，高杂种优势组合的双亲自交系均属于不同类群，而在同一类群自交系间尚未组配出具有高杂种优势的组合；普通玉米自交系的分类结果与以往研究和育种实践相一致，表明SSR标记技术可以用于爆裂玉米自交系间的遗传多样性研究。不同类群爆裂玉米自交系与各类群普通玉米自交系的平均遗传距离为0.549～0.672，应根据两类自交系间的遗传关系对爆裂玉米自交系实施有针对性的分群改良。     

亲本间数量性状遗传距离在高赖氨酸玉米育种中的应用初探

以八个高赖氨酸玉米自交系考查产量品质等16个性状作亲本间遗传距离研究,同时以相应的杂种一代作验证。结果表明,基于性状间遗传相关的主成分值可以较充分地概括众多育种性状的遗传信息,以主成分为基础的遗传距离可以较充分地反映出亲本间的遗传差异,用类平均法比用最短距离法对亲本进行聚类能较好地反映出亲本间的关系。遗传距离与超标优势间不存在明显的相关关系。超亲优势这一参数在高赖氮酸杂种玉米育种中无实际利用价值。一个亲本与其它所有亲本的遗传距离的平均(~2)与该亲本的一般配合力效应(GCA)有曲线关系的趋势。在一定范围内~2与GCA 呈直线关系,r(~2,GCA)=0.7896(P<0.1121)。直线回归方程为GCA=-0.6341+0.8D~2。~2与由该亲本构成的优良组合的比例间存在着显著的线性关系,r(~2,优良组合比例)=0.9027(P<0.05)。因此可望用~2来预测亲本的 GCA 及获得成功的把握性,从而减少实测配合力的大量繁重劳动,提高育种效率。以单位面积赖氨酸产量为指标能较好地概括高赖氮酸玉米育种的目标。     

籽用南瓜优质自交系白粉病抗性初步评价

为了筛选出优质的籽用南瓜白粉病的抗性自交系,在自然发病条件下,鉴定了30份籽用南瓜自交系白粉病的抗病性。结果表明:无免疫和高抗类型;抗病类型为2份,占所有鉴定自交系的6.7%;中抗类型为11份,占所有鉴定自交系的36.7%;其余为感病类型17份,占所有鉴定自交系的56.7%。籽用南瓜自交系对白粉病的抗性都存在显著差异。     

利用SSR标记研究南斯拉夫玉米自交系遗传变异及杂种优势群预测

 利用113对SSR多态性引物对9个南斯拉夫玉米自交系和国内18个不同类群玉米自交系进行遗传多样性分析,进而研究GD,GH,SCA及杂种优势与F₁产量的相关性,探讨预测杂种优势的可能性。结果表明:（1）利用SSR标记将27个供试自交系分为6类,我国自交系的分类结果与其系谱来源和以往研究结果基本一致,PA,PB和四平头类群自交系分别各归为一类;南斯拉夫自交系ZPL01,ZPL06,ZPL09,ZPL10和ZPL02归为第Ⅰ类, ZPL03,ZPL05,ZPL04与Mo17和丹232归为第Ⅱ类群, ZPL07与综3和综31归为第Ⅲ类;（2）SCA与对照优势及其与F₁穗粒重呈极显著正相关,而GD,GH与F₁穗粒重和对照优势的相关仅长葛点达到显著水平,利用SCA或对照优势可以较好地预测F₁的产量表现,而GD和GH的预测效果较差。