马铃薯遗传资源多样性的SRAP分析

采用SRAP分子标记，对44份马铃薯品种的遗传多样性进行了分析。结果显示, 随机抽取27对SRAP引物，对基因组DNA进行特异扩增，其中23对引物扩增出多态性条带，共获得104个多态性条带, 多态性引物比率达85.2%, 平均每对引物产生4.5个多态性条带，表明SRAP标记具有较高的多态性比率。44份种质资源的SRAP标记遗传距离为0.147-0.741。当遗传距离D=0.67时，将44份种质资源分为四大类群，包括一个复合类群和三个独立类群。其中复合类群可进一步分为7个亚群。从而在DNA水平上证明了所研究马铃薯种质资源具有丰富的遗传多样性。     

广西地方食用木薯种质资源遗传多样性分析

为研究广西地方食用木薯材料的遗传多样性,以48份广西地方食用木薯为试验材料,分析其变异系数、遗传多样指数、聚类分析、多态性和遗传相似性系数。结果表明,收集的木薯材料的平均表型变异系数为37.9%,平均遗传多样性指数为0.807,其中主茎分叉角度的变异系数最大,为86.7%,块根内皮颜色的遗传多样性指数最大,为1.842。13对SSR引物共扩增出118个条带,其中多态性条带为106个,多态性比率为86.23%;分子标记聚类结果发现,遗传相似性系数在0.415~1.000之间;通过对比发现表型聚类和分子聚类结果不一致,其中表型聚类发现类群划分与地理来源之间没有关联,但与株型性状有一定的关联;在遗传相似系数为0.62时,SSR分子标记聚类为两类材料,第一类材料地理分布无规律,第二类材料大多分布在桂南。本研究结果表明,广西地方食用木薯资源遗传多样性具有一定的丰富度,可为创制优异食用木薯种质资源和新品种选育奠定基础。     

47份水稻品种资源的ISSR遗传多样性分析

为研究广东省惠州市种植的常规水稻品种的遗传多样性,本实验利用ISSR标记对47份水稻品种资源进行遗传多样性检测。从49条引物中筛选出5条重复性好,条带清晰的引物进行PCR扩增,共扩增出53条带,每个引物可以扩增出9～13条带,平均为10．6条,其中47条具有多态性,比率为88．7％。不同水稻品种间遗传相似系数变幅为0．319～0．936,平均达0．691,说明ISSR标记能够揭示材料间较高的遗传多样性。通过聚类,从分子水平对水稻品种资源的遗传关系进行分析,并对47份水稻品种资源进行分类,ISSR标记能将47份水稻品种完全区分开,为水稻品种资源的研究利用提供参考。     

37份龙眼种质资源亲缘关系的ISSR分析

本研究利用ISSR技术对37份龙眼种质资源进行遗传多样性检测。研究结果表明,从100条ISSR引物中筛选出7条重复性好,条带清晰的引物对37份龙眼品种基因组DNA进行扩增,共扩增出54条带,其中43条具有多态性,比率为79．6％。不同龙眼品种间遗传相似系数变幅为0．69～0．97,平均达0．83,说明ISSR标记能够揭示材料间较高的遗传多样性。UPGMA聚类结果表明,ISSR标记能将37份龙眼品种完全区分开,并能将来源于中国、越南和泰国的37份龙眼品种分别聚类到中国、越南和泰国三大品种群,说明龙眼品种资源的亲缘关系与地理因素有关,三个国家的龙眼品种之间存在较大的遗传差异。本研究结果将为为龙眼品种资源的研究利用提供参考。     

SCoT分子标记在猕猴桃遗传多样性分析与变异鉴定上的应用

我国猕猴桃(Actinidia)种质资源极其丰富,可为猕猴桃遗传改良和资源利用提供广泛的背景材料,而从实生苗群中筛选变种是猕猴桃新品种培育途径之一。本研究以17份猕猴桃品种(系)(其中2份红阳变异系、1份金桃变异系)为材料,采用目标起始密码子多态性(start codon targeted polymorphism,SCoT)对其遗传多样性和变异进行分析。结果表明,基于优化后的适宜于猕猴桃SCoT-PCR反应体系,从64条引物中筛选出42条引物对17份猕猴桃材料扩增出487条清晰的条带,其中多态性条带为470条带,平均多态性比率为95.1%。17份猕猴桃材料之间的遗传距离范围在0.153~0.693,平均值为0.492。变异株桂乐1号、桂乐2号与对照红阳的遗传距离分别为0.276和0.299,金桃变异与金桃的遗传距离为0.539,3个变异株系均与对照有一定的亲缘关系与遗传距离。聚类分析表明,在遗传距离为0.460的水平上,可以将17份猕猴桃材料分为4组。桂乐1号、桂乐2号与对照红阳归为第Ⅲ组,金桃变异与对照金桃则未能聚为同一组。SCoT分子标记可以对猕猴桃性状变异进行初步鉴定,为进一步开展变异新品种的早期鉴定和保护提供技术参考,以及为猕猴桃种质资源遗传多样性分析及其分类提供理论支持。     

利用目标起始密码子多态性(SCoT)分子标记分析梨遗传多样性

目标起始密码子多态性(start codon targeted polymorphism,SCo T)是一种新型的遗传分子标记技术。本研究采用单因素水平设计方法,优化并建立梨的适宜SCo T分子标记体系,通过SCo T标记技术,分析了安徽省砀山县的43份梨(Pyrus spp.)的遗传多样性和亲缘关系。结果表明,优化后梨SCo T-PCR反应体系:10×Easy Taq Buffer(含2 mmol/L Mg2+)2.5μL,模板DNA终浓度30 mg/L,上下游引物终浓度1.0μmol/L,d NTPs终浓度0.2 mmol/L,Taq DNA聚合酶1.0 U,总体积为25μL。随机选取2个DNA模板进行引物筛选,最终从67条引物中筛选出16条扩增条带清晰且有差异性的引物,共扩增出145条带,其中多态性条带有126条,多态性比率为86.1%,每条引物平均扩增出9.1条带。SCo T标记的43个梨材料遗传相似性系数为0.517~0.931,平均值为0.685。聚类分析表明,在遗传相似系数为0.610的水平上,43份梨材料分为A和B两组;在遗传相似系数为0.746的水平上,A组又分为6个亚组(Ⅰ~Ⅵ)。所研究的43份梨材料具有丰富的遗传多样性,且能够被SCo T分子标记有效地检验,为进一步研究利用安徽省砀山县梨种质资源提供了依据。     

利用小麦SSR标记分析鸭茅种质资源的遗传多样性

使用小麦(Triticum aestivum)SSR引物和扩增程序,以中国春小麦(T. aestivum)品种为对照,利用SSR标记对来自国内外的45份鸭茅(Dactylis glomerata L.)种质资源进行遗传多样性研究.结果表明,20对引物扩增出295个条带,多态性条带为187条,多态性条带比率为61.15%,鸭茅种质资源的遗传相似系数范围为0.7848～0.9513.聚类分析和主成分分析将供试材料分为6大类,聚类结果不仅能反映鸭茅生态适应性特征与其生长发育状况及生产性能相关,还显示出国产鸭茅品种遗传基础较为狭窄.研究表明将小麦SSR引物用于检测鸭茅遗传多样性行之有效.     

中国96个荔枝种质资源的EST-SSR遗传多样性分析

根据本实验室已获得的荔枝果皮cDNA文库EST序列,通过SSRIT在线检索,从3391条EST序列中,发现305条含有SSR,占整个文库EST的8.99%。利用SSR-ESTs序列共设计100对EST-SSR引物,其中62对在荔枝上有扩增产物,50对有扩增多态性,即具有一定的通用性。接着从96份荔枝种质中选取12个品种的基因组DNA,开展核心引物筛选,共筛选出多态性较好的EST-SSR分子标记30个;这30个EST-SSR分子标记在96份资源共扩出284条带,不同引物的扩增条带在3～18条之间,平均9.47条,其中有282条为多态性带,多态率高达99.30%,每对引物的Nei＇s基因多样度范围为0.186～0.396,香农信息指数范围为0.318～0.558;此外,系统聚类分析结果表明,在相似系数0.5525处,可将96份荔枝种质资源分成了8大类群,该8大类群基本与其生态类型和植物学性状特征相符。在此基础上,还对荔枝的主栽品种和特殊种质进行鉴别,结果表明,该30个EST-SSR分子标记在不同品种间可产生较清晰可辨的多态性差异,为荔枝品种以及种质资源鉴别和鉴定的分子指纹的构建奠定了良好基础。     

中国西南区扁穗牛鞭草种质遗传多样性的SRAP分析

本研究采用SRAP标记对主要来自中国西南地区（四川,重庆,贵州和云南）的43份扁穗牛鞭草种质资源的遗传多样性进行了分析。试验筛选出了11对引物组合对43份供试材料进行扩增,共获得153条带,其中多态性条带140条,多态性条带比率为91.50%,平均每对引物扩增出条带13.91,多态性条带12.73。实验数据结果表明,43份扁穗牛鞭草材料间的遗传相似系数（GS）为0.565～0.992,平均值为0.723,表现出了丰富的遗传多样性。聚类分析结果表明,各供试材料间的聚类与其地理来源以及形态特征类型具有一定的相关性。同时,主成分分析结果能够直观的反映了各种质间的遗传关系。5个扁穗牛鞭草地理类群间的分子方差分析（AMOVA）揭示了供试的扁穗牛鞭草总遗传变异的85.99%存在于类群内,仅有14.01%的变异存在于类群之间,类群间的分化系数ΦST=0.140。本研究结果为扁穗牛鞭草种质的收集、利用及育种提供了理论依据。     

大蒜种质遗传多样性的SSR分析

为了探索中国大蒜种质个体的SSR位点的分布情况,为品种鉴定、保存及遗传改良提供分子生物学依据,利用6对SSR引物对40个大蒜(Allium sativumL.)品种进行聚类分析、主成分分析及遗传多样性评价。共检测到21个多态性位点,平均每对引物可扩增出约3.5条多态性片段,多态性百分率为56.76%;SSR引物组合平均有效等位基因数、Nei基因多样度和Shannon信息指数分别为1.5551、0.3414和0.5188。聚类分析显示,6对SSR引物可把40份大蒜种质资源从0.59相似系数水平上3个类群。第一类群包含28份种质,在相似系数为0.73的水平上进一步又被分成了3个亚类;第二亚类仅包含2份种质;第三亚类包含10份种质,在0.68的相似系数水平上分成了2个亚类。主成分分析和UPGMA的结果基本一致。不同地理来源的大蒜种质的Shannon-Weaver多样性指数的变幅为0.0576~0.4179,说明大蒜种质遗传多样性丰富。本研究利用SSR分子标记技术较准确地解析大蒜不同材料间的亲缘关系及遗传多样性,为中国大蒜SSR分子标记提供基础资料。     

Genetic diversity and phylogenetic relationship of <Emphasis Type="Italic">Tadehagi</Emphasis> in southwest China evaluated by inter-simple sequence repeat (ISSR)

There are many valuable Tadehagi accessions in southwest China, but it is unknown that the genetic diversity and phylogenetic relationship of these Tadehagi resources. This report is the first study in which 41 primers of inter-simple sequence repeat (ISSR) were used to assess the genetic diversity of 36 Tadehagi accessions from 3 provinces in the southwest of China. Totally, 30 usable ISSR primers detected 163 polymorphic bands among the 36 accessions, which suggested high utility of ISSR primers in the genetic analysis of Tadehagi accessions. Genetic similarity coefficients among all of the accessions ranged from 0.54 to 0.92 with the average of 0.79 based on the ISSR data, indicating high level of genetic variation in Tadehagi resources from the southwest of China. As for the 3 population, Hainan population had the maximum average genetic similarity coefficients of 0.81, while similarity coefficient of Guangxi and Yunnan population was 0.75 and 0.74, respectively. All the 36 Tadehagi accessions were divided into 4 groups in the UPGMA dendrogram constructed from genetic similarity coefficients. The Tadehagi accessions from Yunnan and Guangxi provinces showed more genetic variation and occupied the bottom of the dendrogram. On the contrary, those from Hainan Province had less genetic variation and clustered in the middle and top of the dendrogram. The information on the genetic diversity and phylogenetic relationship from this study is propitious to construct a core germplasm collection and develop novel Tadehagi cultivars with desired economic traits.     

Genetic relationship and diversity of Mangifera indica L.: revealed through SCoT analysis

Mango (Mangifera indica L.) is one of the most economically grown fruits in the tropical and subtropical areas around the world. In the present study, start codon targeted (SCoT) markers were employed to investigate the genetic diversity of 73 mango accessions obtained from Guangxi province, China. A total of 275 bands were amplified by thirty-four SCoT primers, of which 203 (73.82%) were polymorphic. Genetic similarity between accessions was in the range of 66.2–94.2% with an average of 78.8%. The observed highest genetic similarity value (94.2%) was found between ‘Ren Mian Mango’ and ‘Hong Hua Mango’, the observed lowest genetic similarity value (66.2%) was found between‘Xia Mao Xiang Mango’ and ‘India No. 15’. These coefficients were utilized to construct a dendrogram using the unweighted pair group of arithmetic means. All the accessions were grouped into four (A, B, C, D) clusters and correspond well with their geographical origin and their known history. These results have an important implication for mango’s rue germplasm characterization, improvement, management and conservation.     

Genetic diversity and relationships among safflower (<Emphasis Type="Italic">Carthamus tinctorius</Emphasis> L.) analyzed by inter-simple sequence repeats (ISSRs)

Genetic diversity and relationships among 48 safflower accessions were evaluated using 22 inter-simple sequence repeats (ISSR) primers. A total of 429 bands were amplified, and 355 bands (about 82.7%) were polymorphic. Five to forty-one polymorphic bands could be amplified by each primer, with an average of 16.1 polymorphic bands per primer. The results showed that the polymorphism of the safflower germplasm was higher at the DNA level. All the 48 accessions could be distinguished by ISSR markers and were divided into 9 groups based on ISSR GS by using UPGMA method. The genetic relationships among the accessions from different continents were closer. Comparatively, the genetic diversity of the accessions originated from Asia was higher, from Europe assembled. The results also showed that the genetic variation of accessions from Indian and Middle Eastern safflower diversity centers were relatively higher. ISSR is an effective and promising marker system for detecting genetic diversity among safflower and give some useful information on its phylogenic relationships.     

Genetic Diversity among the Germplasm Resources of the Genus <Emphasis Type="Italic">Houttuynia</Emphasis> Thunb. in China based on RAMP Markers

The genetic diversity of 70 Houttuynia Thunb. accessions from Sichuan, Chongqing, Guizhou and Jiangsu province in China were tested by using random amplified microsatellite polymorphism (RAMP) markers. All of the 43 primer combinations were found to amplify polymorphic products. A total of 304 products were amplified. Of which, 97.7 products were polymorphic. 6.9 polymorphic bands were amplified by each primer combination on average. The genetic similarity (GS) between the accessions within H. emeiensis and H. cordata were 0.660 and 0.575, respectively. The GS between two species was 0.525. The GS values between H. emeiensis and the H. cordata cytotype with the chromosome number of 36 was 0.559, higher than that between H. emeiensis and the cytotypes of H. cordata with other chromosome numbers. Within the species H. cordata, the genetic variation between cultivated and wild accessions was insignificant. The results of cluster analysis by using UPGMA method showed that all the tested accessions could be differentiated by RAMP markers, and classified into 11 groups. Many accessions with the same chromosome numbers could be classified together. The genetic diversity was more plentiful in mountainous and margin areas of the Sichuan Basin than at the bottom of the Basin and the highlands or hills surrounding it. It was concluded that there existed higher genetic diversity at the molecular level (RAMP markers) among the germplasm resources of the genus Houttuynia. The genetic relationships and phylogeny of the germplasm resources of Houttuynia were also discussed.     

Characterization of genetic variation and relationships among Choix germplasm accessions using RAPD markers

Choix, a plant in the tribe Maydeae of the grass family, has been cultivated in Asia for several thousand years. It is a potential gene resource for improvement of other cereal crops because of its nutritional value and tolerance to stress. Genetic variation and relationships among 21 Choix lachryma-jobi L. accessions were characterized by random amplified polymorphic DNA (RAPD) markers. A total of 205 DNA fragments across all materials were amplified with 31 random primers, averaging 6.61 per primer. Among amplified fragments, 115 showed polymorphism averaging 3.71 per primer. Of amplified markers, 56.1% were polymorphic, indicating considerable variation at the DNA level among these accessions. Some fragments were accession-specific. Pair-wise genetic similarity (GS) among 21 accessions ranged from 0.809 to 0.301. The 21 accessions clustered into two major groups. Three exotic Choix accessions clustered together. Three other Choix accessions, collected from Guangxi, China, clustered into a cohesive subgroup. Four wild types of Choix clustered into the same subgroup. These results indicated that the classification by RAPD data reflected the differences in geographic origins and evolution in Choix.     

青藏高原野生老芒麦种质醇溶蛋白遗传多样性分析

采用酸性聚丙烯酰胺凝胶电泳(A-PAGE) 对采集自青藏高原的54份野生老芒麦（Elymus sibiricus L.）种质进行遗传多样性分析,获得下述结果:（1）供试材料共分离出42条带纹,多态率达92.86%。4个电泳分区（α、β、γ、ω）的平均Shannon指数为0.4627,Nei-Li遗传相似系数（GS）变异范围为0.2424~0.9767,平均值为0.5822。说明供试野生老芒麦材料具有较为丰富的醇溶蛋白遗传多样性。（2）对所有材料的聚类分析和主成分分析发现,在GS值为0.562的水平上供试材料可聚成4个大类,绝大部分来自于相同或相似生态地理环境的材料聚成一类,主成分分析显示了相似的结果,即醇溶蛋白图谱类型与材料的生态地理环境具有一定的相关性。（3）基于Shannon 多样性指数估算了5个老芒麦地理类群内和类群间的遗传分化,发现类群内遗传变异占总变异的68.17%,而类群间的遗传变异占总变异的31.83 %。（4）对各地理类群基于Nei氏无偏估计的遗传一致度的聚类分析表明,各地理类群间的遗传分化与其所处的地理生态环境具有较高的相关性。     

The genetic characterization of Turkish watermelon (<Emphasis Type="Italic">Citrullus lanatus</Emphasis>) accessions using RAPD markers

Genetic diversity of the Turkish watermelon genetic resources was evaluated using different Citrullus species, wild relatives, foreign landraces, open pollinated (OP) and commercial hybrid cultivars by RAPD markers. The germplasm was consisted of 303 accessions collected from various geographical regions. Twenty-two of 35 RAPD primers generated a total of 241 reproducible bands, 146 (60.6%) of which were polymorphic. Based on the RAPD data the genetic similarity coefficients were calculated and the dendrogram was constructed using UPGMA (Unweighted pair-group method with arithmetic average). Cluster analysis of the 303 accessions employing RAPD data resulted in a multi-branched dendrogram indicating that most of the Turkish accessions belonging to var. lanatus of Citrullus lanatus (Thunb.) Matsum et Nakai were grouped together. Accessions of different Citrullus species and Praecitrullus fistulosus (Stocks) Pangalo formed distant clusters from C. lanatus var. lanatus. Among 303 accessions, a subset of 56 accessions was selected representing different groups and a second dendrogram was constructed. The genetic similarity coefficients (GS) within the Turkish accessions were ranged from 0.76 to 1.00 with 0.94 average indicating that they are closely related. Taken together, our results indicated that low genetic variability exist among the watermelon genetic resources collected from Turkey contrary to their remarkable phenotypic diversity.     

Interrelationships among Coconut (Cocos Nucifera L.) Accessions Using RAPD Technique

The genetic relationships among 33 coconut germplasm accessions were analyzed using RAPD markers. The germplasm accessions were collected from various coconut growing regions viz. South Asia (SA), South East Asia (SEA), South Pacific (SP), Atantic and America, and Africa. Forty-five random primers produced a total of 399 polymorphic markers. The Polymorphism Information Content (PIC) ranged from 0.031 to 0.392 and the Marker Index (MI) ranged from 6.28 to 0.031 among the primers. Based on the MI a set of 5, 10 and 15 informative and reproducible primers were identified. The mantel matrix correlation was calculated to compare the similarity matrices of a set of reproducible informative primers and global primers. There was significant correlation among the similarity matrices (r ≥ 0.50). The similarity matrix based on 399 polymorphic markers was used to construct the dendrogram to show the genetic relationship among the accessions. Similarity values ranged between 0.573 and 0.846. There was less genetic similarity (based on Jaccard's coefficient) among South Pacific and South East Asian accessions. The clustering pattern obtained in the present study was in agreement with the earlier reports based on RFLP, SSRs and AFLPs.