Analysis of genetic diversity in a sweet potato (Ipomoea batatas L.) germplasm collection from Tanzania as revealed by AFLP

Sweet potato (Ipomoea batatas L.) is the fifth most important crop in the developing countries after rice, wheat, maize and cassava. The amplified fragment length polymorphism (AFLP) method was used to study the genetic diversity and relationships of sweet potato accessions in the germplasm collection of Sokoine University of Agriculture, Morogoro and Sugarcane Research Institute, Kibaha, Tanzania. AFLP analysis of 97 sweet potato accessions using ten primer combinations gave a total of 202 clear polymorphic bands. Each one of the 97 sweet potato accessions could be distinguished based on these primer combinations. Estimates of genetic similarities were obtained by the Dice coefficient, and a final dendrogram was constructed with the un-weight pair-group method using arithmetic average. AFLP-based genetic similarity varied from 0.388 to 0.941, with a mean of 0.709. Cluster analysis using genetic similarity divided the accessions into two main groups suggesting that there are genetic relationships among the accessions. Principal Coordinate analysis confirmed the pattern of the cluster analysis. Analysis of molecular variance revealed greater variation within regions (96.19%) than among regions (3.81%). The results from the AFLP analysis revealed a relatively low genetic diversity among the germplasm accessions and the genetic distances between regions were low. A maximally diverse subset of 13 accessions capturing 97% of the molecular markers diversity was identified. We were able to detect duplicates accessions in the germplasm collection using the highly polymorphic markers obtained by AFLP, which were found to be an efficient tool to characterize the genetic diversity and relationships of sweet potato accessions in the germplasm collection in Tanzania.     

Simple sequence repeats marker polymorphism in emmer wheat (<Emphasis Type="Italic">Triticum dicoccon</Emphasis> Schrank): Analysis of genetic diversity and differentiation

Genetic diversity was investigated in 73 accessions of emmer wheat (Triticum dicoccon Schrank) from 11 geographical regions using a set of 29 simple-sequence repeat (SSR or microsatellite) markers, representing at least two markers for each chromosome. The SSR primers amplified a total of 357 different alleles with an average of 12.31 alleles per locus. The number of fragments detected by each primer ranged between 6 (Xgwm1066) and 21 (Xgwm268). Null alleles were detected in nine of the 29 primers used. A high level of gene diversity index was observed. Across the 29 primers, gene diversity ranged from 0.60 (Xgwm46) to 0.94 (Xgwm655), with a mean of 0.82. There was a highly significant correlation (r=0.882; p<0.01) between gene diversity index and the number of loci, showing the number of loci per se is a strong indicator of diversity. Analysis of genetic diversity within and among eleven geographical regions revealed most of the genetic diversity of the total sample resided within regions. The coefficient of gene differentiation (Gst = 0.27) showed that the genetic variation within and among the 11 geographical regions was 73 and 27%, respectively. High value of mean number of alleles per locus was found in Iran (4.86) followed by Morocco (4.10) and Armenia (4.03). On the contrary, lower mean number of alleles per locus was detected in Yemen (2.83). The average gene diversity index across regions ranged from 0.52 (Slovakia) to 0.67 (Morocco) with an average of 0.60. Multivariate techniques of principal component analysis and clustering were employed to examine genetic relationship among the 73 emmer wheat accessions vis-à-vis geographical regions of collections. The genetic distance coefficients for all possible 55 pairs of regional comparisons ranged from 0.63 (between Iran and Armenia, Georgia and Azerbaijan, Georgia and Slovakia) to 0.97 (between Morocco and Yemen, Spain and Georgia, and Turkey and Iran) with a mean of 0.82. From the PCA results, a two dimensional plot of PC1 versus PC2 was constructed. The scatter plot of the first two principal components which explained altogether 27% of the total variation depicted the presence of a clear pattern of geographical differentiation except in few cases like accessions from Caucasian region. Similar pattern of genetic relationships among accessions was observed in cluster analysis. The study provided genetic information of emmer wheat in relation to geographical regions of origin. The information could be utilized in crop improvement, germplasm conservation programs, and in further investigation.     

Genetic Diversity Among Traditional Ethiopian Highland Maize Accessions Assessed by Simple Sequence Repeat (SSR) Markers

Over the past three centuries, maize has become adapted to complex environmental conditions in the highlands of Ethiopia. We analyzed 62 traditional Ethiopian highland maize accessions, using 20 simple sequence repeat (SSR) markers and 15 morphological traits, to assess genetic diversity and relationships among these accessions and to assess the level of correlation between phenotypic and genetic distances. The accessions varied significantly for all of the measured morphological traits. The average number of alleles per locus was 4.9. Pair-wise genetic dissimilarity coefficients ranged from 0.27 to 0.63 with a mean of 0.49. Ward minimum variance cluster analysis showed that accessions collected from the Northern agroecology were distinct from the Western and Southern agroecologies. However, there was no differentiation between the Western and Southern accessions. This suggested gene flow between these regions. The relationship between morphological and SSR-based distances was significant and positive (r = 0.43, p = 0.001). The high genetic diversity observed among these set of accessions, suggests ample opportunity for the development of improved varieties for different agroecologies of Ethiopia. From conservation perspective, sampling many accessions from all agroecologies would be an effective way of capturing genetic variation for future collections and conservation.     

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。     

Spatially structured genetic diversity of the Amerindian yam (Dioscorea trifida L.) assessed by SSR and ISSR markers in Southern Brazil

Dioscorea trifida L. (Dioscoreaceae) is among the economically most important cultivated Amerindian yam species, whose origin and domestication are still unresolved issues. In order to estimate the genetic diversity maintained by traditional farmers in Brazil, 53 accessions of D. trifida from 11 municipalities in the states of São Paulo, Santa Catarina, Mato Grosso and Amazonas were characterized on the basis of eight Simple Sequence Repeats (SSR) and 16 Inter Simple Sequence Repeats (ISSR) markers. The level of polymorphism among the accessions was high, 95 % for SSR and 75.8 % for ISSR. The SSR marker showed higher discrimination power among accessions compared to ISSR, with D parameter values of 0.79 and 0.44, respectively. Although SSR and ISSR markers led to dendrograms with different topologies, both separated the accessions into three main groups: I—Ubatuba-SP; II—Iguape-SP and Santa Catarina; and III—Mato Grosso. The accessions from Amazonas State were classified in group II with SSR and in a separate group with ISSR. Bayesian and principal coordinate analyzes conducted with both molecular markers corroborated the classification into three main groups. Higher variation was found within groups in the AMOVA analysis for both markers (66.5 and 60.6 % for ISSR and SSR, respectively), and higher Shannon diversity index was found for group II with SSR. Significant but low correlations were found between genetic and geographic distances (r = 0.08; p = 0.0007 for SSR and r = 0.16; p = 0.0002 for ISSR). Therefore, results from both markers showed a slight spatially structured genetic diversity in D. trifida accessions maintained by small traditional farmers in Brazil.     

SSR Diversity of Vegetable Soybean [<Emphasis Type="Italic">Glycine max</Emphasis> (L.) Merr.]

Edamame [Glycine max (L.) Merr.] is a type of soybean selected for fresh or frozen vegetable use at an immature stage. Since edamame has a similar protein content, milder flavor, nuttier texture, and is easier to cook when compared to grain soybean, it is being promoted as a new vegetable for global consumption. Global production will require breeding programs for local adaptation; however, limited research has been published on genetic diversity of edamame varieties for the assessment of genetic resources. Simple sequence repeats (SSRs) were used to study the genetic diversity among 130 accessions, including edamame cultivars and landraces from Japan, China and the US, and also the new breeding lines in the US. Although it is assumed that elite edamame cultivars would have narrow genetic diversity, seventeen SSRs detected polymorphism to distinguish 99 of the 130 accessions. The cluster analysis generated nine clusters and 18 outliers. Genetic diversity within Japanese edamame was lower than that within Chinese vegetable soybean accessions (maodou), even though only 10 Chinese maodou were analyzed compared to 107 Japanese edamame. Cluster analysis revealed that the patterns of SSR diversity in edamame can generally distinguish maturity classes and testa color. We concluded that Japanese edamame have a narrow genetic base different from others and that SSRs can describe the patterns of genetic diversity among the elite vegetable soybean.     

Genetic Diversity of Asian Cotton (Gossypium arboreum L.) in China Evaluated by Microsatellite Analysis

Asian cotton (Gossypium arboreum L.) was once widely cultivated in China. It has also been a valuable source of genetic variation in modern cotton improvement. In this study, the genetic diversity of selected G. arboreum accessions collected from different regions of China was evaluated by microsatellite (simple sequence repeats, SSRs) analysis. Of the 358 microsatellite markers analyzed, 74 primer pairs detected 165 polymorphic DNA fragments among 39 G. arboreum accessions examined. Twelve accessions could be fingerprinted with one or more SSR markers. With the exception of two accessions, DaZiJie and DaZiMian, genetic similarity coefficients among all accessions ranged from 0.58 to 0.87 suggesting high level of genetic variation in the G. arboreum collections. The UPGMA dendrogram constructed from genetic similarity coefficients revealed positive correlation between cluster groupings and geographic distances. In addition, comparison of the microsatellite amplification profiles of the diploid G. arboreum and tetraploid Gossypium hirsutum L. found that size distribution of amplified products in G. arboreum was dispersive and that of G. hirsutum was relatively concentrated. The information on the genetic diversity and SSR fingerprinting from this study is useful for developing mapping populations for constructing diploid cotton genetic linkage map and tagging economically important traits.Diqiu Liu, Xiaoping Guo: These two authors contributed equally to this work.     

Preliminary study of genetic diversity in Swedish flax (Linum usitatissimum)

To investigate the genetic diversity of Linum usitatissimumL. in Sweden, 18 accessions, including 13 cultivars and five landraces, were analysed. This study was based on genetic variation in three enzyme systems (i.e., PGD, GPI and MDH) by using horizontal starch gel electrophoresis. The total genetic diversity of the studied flax material was very high (H _T= 0.62). Even though the highest genetic diversity lies within the accessions (G _ST= 0.07), a clear differentiation between fibre and oil flax was found with respect to three polymorphic loci (Pgd-1, Gpi-2 and Mdh-1). A phenogram, based on Nei's genetic distances between the accessions studied, showed five clearly defined groups but with low variation within the groups. The unexpected high genetic diversity found within accessions in the studied flax material may indicate that flax is more outbreeding than earlier believed.     

Genetic diversity of <Emphasis Type="Italic">Nelumbo</Emphasis> accessions revealed by RAPD

Total 65 lotus accessions in genus Nelumbo mainly collected from China, were subjected to random amplified polymorphic DNA (RAPD) markers to estimate the genetic diversity and to test the genetic basis of the relationships between morphotypes and molecular markers. Seventeen primers generated a total of 195 highly reproducible and discernible loci, among which 173 were polymorphic. Percent polymorphism varied from 66.7 to 100 with an average of 88.72, and five primers out of them, OPC05, OPG10, OPN20, OPP09 and OPS17, showed 100% polymorphism. A relatively high genetic diversity was detected among all the samples with the similarity coefficient values ranging from 0.45 to 0.85, and Nei’s gene diversity (h) 0.30, and Shannon index (I) 0.46. The UPGMA dendrogram clustered 65 accessions in four clusters and the clustering pattern showed two groups, N. nucifera ssp. nucifera and those accessions related to the American lotus, and some special cultivars, landraces, hybrids and the American lotus. Principal Coordinate Analysis (PCA) further indicated that the genetic diversity of Nelumbo accessions was not evenly distributed, instead, was presented by a clustered distribution pattern. Similar to the results revealed by the dendrogram, two main groups representing the two subspecies of N. nucifera, as well as some special landraces, cultivars of Chinese lotus, the Japanese lotus and hybrids out of the two groups were obtained. Neither the UPGMA dendrogram nor the PCA analysis exhibited strict relationship with geographic distribution and morphotypes among the accessions.     

Diversity analysis of Central Asia and Caucasian lentil (<Emphasis Type="Italic">Lens</Emphasis><Emphasis Type="Italic">culinaris</Emphasis> Medik.) germplasm using SSR fingerprinting

Diversity analysis was performed among 39 cultivated lentil (Lens culinaris Medik.) accessions of Central Asia and Caucasian origin using five highly polymorphic microsatellite markers. A total of 33 alleles determined ranging from 3 to 8 per locus. Estimated gene diversity value for 33 loci was 0.66. Genetic similarity indices among 39 accessions ranged from 0.24 to 1.0. Cluster analysis using the unweighted pair group method with arithmetic mean method classified accessions into six major groups at 0.5 similarity coefficient. More than half accessions from Tajikistan formed large cluster. On the other hand, a few accessions from each country showed unique genotypes. Overall, most of the accessions, except ones with closely related origin, were distinguished by the present high quality DNA fingerprinting. This molecular diversity information gives important basis for conservation strategy in gene bank and exotic germplasm introduction in breeding programs in Central Asia and Caucasian countries.     

Genetic characterization of guava (Psidium guajava L.) germplasm in the United States using microsatellite markers

Genetic diversity of 35 Psidium guajava L. accessions and three related species (P. guineense Sw., P. sartorianum (O. Berg) Nied. and P. friedrichsthalianum (O. Berg) Nied.) maintained at the U.S. Department of Agriculture (USDA), National Plants Germplasm System, Hilo, HI, was characterized using 20 simple sequence repeat (SSR) markers. Diversity analysis detected a total of 178 alleles ranging from 4 to 16 alleles per locus. The observed mean heterozygosity (0.2) and inbreeding coefficient (0.8) indicated a high level of inbreeding among the accessions tested. Multi-locus DNA fingerprints based on the 20 SSR loci unambiguously differentiated all accessions and revealed the absence of duplicated samples. Ordination and cluster analyses suggested that the genetic relationships between majorities of the accessions could be explained by geographic origin, mainly including tropical America, Southeast Asia and Hawaii. A Bayesian cluster analysis partitioned the accessions into two groups and the partition was largely compatible with the result of ordination analyses. Distance-based cluster analyses further indicated that accessions from same geographical region or breeding programs grouped together in spite of the inter-regional exchange of germplasm. Accessions from Southeast Asia were dominantly white fleshed, whereas accessions from tropical America and Hawaii exhibited diverse flesh colors. The results also indicated that accessions from the same region were likely derived from a small number of common ancestors or progenitors. All 20 SSRs were transferable to P. guineense, P. sartorianum and P. friedrichsthalianum, indicating a close relationship between the cultigens and wild relatives. Application of SSR markers in the USDA/Agricultural Research Service germplasm collection provides new insight into the diversity of the guava germplasm, which will be valuable in future breeding endeavors and the conservation of guava genetic resources.     

A wide range of genetic diversity in pear (<Emphasis Type="Italic">Pyrus ussuriensis</Emphasis> var. <Emphasis Type="Italic">aromatica</Emphasis>) genetic resources from Iwate,Japan revealed by SSR and chloroplast DNA markers

Iwateyamanashi (Pyrus ussuriensis var. aromatica) is one of the Pyrus species which grows wild in Japan. The number of Iwateyamanashi trees has been decreasing, so conservation and evaluation is urgently needed. Over 500 accessions of Pyrus species collected from Iwate in northern Tohoku region are maintained at Kobe University as an Iwateyamanashi germplasm collection. In order to investigate the genetic diversity, five SSR (simple sequence repeat) markers, developed from Japanese and European pear were examined for 86 Pyrus individuals including 58 accessions from Iwate. These SSR loci could discriminate between all the Iwate accessions except for 10 that bear seedless fruit, as well as determine the genetic diversity in Iwateyamanashi germplasms. High levels of variation were detected in 41 alleles and the mean observed heterozygosity across 5 loci was 0.50 for the Iwate accessions. Seedless accessions sharing identical SSR genotype with the local pear variety “Iwatetanenashi” were supposed to have been propagated vegetatively via grafting. In an UPGMA phenogram, Japanese pear varieties (P. pyrifolia) were clustered into two groups with some Iwate accessions including seedless ones. Another 38 Iwate accessions were not clustered clearly, and there was no clear relationship between these accessions and geographical distribution or morphological characters. Allele frequency revealed that the Iwate accessions were genetically more divergent than the Japanese pear varieties. Most Japanese pears possessed a 219 bp deletion at a spacer region between the accD and psaI genes in the chloroplast DNA (cpDNA), but other Pyrus species and two Iwateyamanashi trees did not. In the Iwate accessions, 79.3% had a deletion type cpDNA and others had a standard type cpDNA without deletion. These results are indicative of the wide range of genetic diversity in the Iwate accessions which include Japanese pear varieties. A combination of SSR and cpDNA analyses revealed high heterogeneity in Iwateyamanashi and coexistence of Iwateyamanashi and hybrid progeny with P. pyrifolia. These could be reasons for the wide range of continuous morphological variation described previously.     

Analysis of Genetic Diversity in the Brassica napus L. Gene Pool Using SSR Markers

Genetic diversity throughout the rapeseed (Brassica napus ssp. napus) primary gene pool was examined by obtaining detailed molecular genetic information at simple sequence repeat (SSR) loci for a broad range of winter and spring oilseed, fodder and leaf rape gene bank accessions. The plant material investigated was selected from a preliminary B. napus core collection developed from European gene bank material, and was intended to cover as broadly as possible the diversity present in the species, excluding swedes (B. napus ssp. napobrassica (L.) Hanelt). A set of 96 genotypes was characterised using publicly available mapped SSR markers spread over the B. napus genome. Allelic information from 30 SSR primer combinations amplifying 220 alleles at 51 polymorphic loci provided unique genetic fingerprints for all genotypes. UPGMA clustering enabled identification of four general groups with increasing genetic diversity as follows (1) spring oilseed and fodder; (2) winter oilseed; (3) winter fodder; (4) vegetable genotypes. The most extreme allelic variation was observed in a spring kale from the United Kingdom and a Japanese spring vegetable genotype, and two winter rape accessions from Korea and Japan, respectively. Unexpectedly the next most distinct genotypes were two old winter oilseed varieties from Germany and Ukraine, respectively. A number of other accessions were also found to be genetically distinct from the other material of the same type. The molecular genetic information gained enables the identification of untapped genetic variability for rapeseed breeding and is potentially interesting with respect to increasing heterosis in oilseed rape hybrids.     

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。     

Spatial patterns of diversity and genetic erosion of traditional cassava (<Emphasis Type="Italic">Manihot esculenta</Emphasis> Crantz) in the Peruvian Amazon: An evaluation of socio-economic and environmental indicators

This study evaluates quantitatively the suitability of the use of site-specific socio-economic and environmental data as indicators to rapidly assess patterns of diversity and genetic erosion risk in cassava. Socio-economic data as well as farmers’ estimation of genetic erosion were collected in the study area, the Ucayali region of the Peruvian Amazon, through interviews with 285 cassava farmers in 50 communities, while diversity was assessed based on agromorphological characterization of 295 cassava accessions. Using multivariate regression analyses, 50 and 45% of the variation in respectively diversity and genetic erosion estimation could be explained by a selected set of socio-economic and environmental indicators. In both regression models four out of the total of 38 variables proved to contribute significantly (at p < 0.10 level). Additionally, the study revealed that farmers are a good direct source of information on the diversity present at community level, which can contribute to the development of methodologies to assess diversity more rapidly. The results of this study are valuable for the development of models to rapidly assess diversity dynamics in large areas.     

Extent and Pattern of Genetic Diversity for Morpho-agronomic Traits in Ethiopian Highland Pulse Landraces: I. Field Pea (<Emphasis Type="Italic">Pisum sativum</Emphasis> L.)

An experiment was conducted in 2001 at Holetta and Kulumsa, Ethiopia, to study the extent and pattern of genetic diversity in Ethiopian field pea (Pisum sativum L.) landraces. One hundred forty-eight germplasm accessions were grown in an alpha lattice design with 2 replications. Data on 12 traits were collected and analyzed. Differences among the accessions were significant for most of the traits (except number of seeds/ pod) at each location even though differences pooled over location were mostly non-significant. The accessions were grouped into five clusters of different sizes. Accessions from the southern part of the country (Arsi) distributed overall clusters while those from the northern half (North and South Wello, North Gonder and North Shewa) fell into clusters C₁ to C₃. Cumulative effects of a number of characters dictated differentiation of the accessions into clusters. There was no definite relationship between geographic diversity and genetic diversity as overlapping was encountered in clustering pattern among accessions from different parts of the country. Accessions from different regions might have similar genetic background and those from the same origin might also have different genetic background. Therefore, geographic diversity should not necessarily be used as an index of genetic diversity and parental selection should be based on a systematic study of genetic diversity in a specific population. Genetic distances among most of the clusters were significant that crosses between parents selected out of them are expected to generate desirable genetic recombination. Selection should also consider the special advantages of each cluster and each accession within a cluster. Future germplasm collection, conservation and breeding efforts should focus not only on inter-regional diversity but also on intra-regional diversity.     

Molecular differentiation,diversity, and folk classification of “sweet” and “bitter” cassava (<Emphasis Type="Italic">Manihot esculenta</Emphasis>) in Caiçara and Caboclo management systems (Brazil)

This study focuses the inter-relationships among the men, the use, and the intra-specific cassava diversity, under the perspective of this crop evolutionary dynamics. The origin, the use and the current local management of varieties with high and low cyanogenic potential are important questions around cassava domestication. We collected 169 local varieties identified as “sweet” or “bitter” cassava by traditional farmers from Atlantic Forest and Amazon (Medium Negro River Basin), Brazil. Using a population genetics and an ethnobotany approach, the diversity and the genetic structure of cassava were evaluated. We found a total of 115 vernacular names, and in the Atlantic Forest sample the average genetic diversity (H _S = 0.654) was higher for the sweet varieties than for bitter ones (0.582). The genetic differentiation coefficient (R _ST), used to estimate the diversity among groups, was 0.057 (P < 0.001), indicating that the divergence between the two groups is low. We obtained a low correlation between the morphological and genetic distances, and the congruence was high when the ethnoclassification and the genetic structure were considered. We discuss the adaptive advantages of the sweet varieties use, the current socio-economic changes in bitter varieties use, and the ecological history of these variety groups.     

黄淮麦区部分小麦种质资源的遗传差异分析

利用79对SSR引物对黄淮麦区129份种质资源进行了分析。结果表明,79对引物共检测到335个等位变异,每个引物检测到的等位变异数目2～8个,平均4.240个,变异最大的位点主要位于B组染色体上。79个SSR位点的遗传多态性信./010.015～0.820之间,平均0.498。种质资源间的遗传相似系数在0.253～0.909之间,平均0.492。聚类分析把这些种质45674大类和7个亚类。聚类结果与地域并不吻合,但能较好地反映出亲本的特性和其间的亲缘关系。     

黄淮麦区部分小麦种质资源的SSR聚类分析

利用79对SSR引物对黄淮麦区129份种质资源进行了分析。结果表明, 79对引物共检测到335个等位变异，每个引物检测到的等位变异数目2～8个，平均4.240个，变异最大的位点主要位于B组染色体上。79个SSR位点的遗传多态性信息含量在0.015～0.820之间，平均0.498。种质资源间的遗传相似系数在0.253～0.909之间，平均0.492。聚类分析把这些种质资源分为4大类和7个亚类。聚类结果与地域并不吻合，但能较好地反映出亲本的特性和其间的亲缘关系。关键词：黄淮麦区；小麦；种质资源；遗传多样性；SSR标记；聚类分析