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1.
Abdelhameed Elameen Siri Fjellheim Arild Larsen Odd Arne Rognli Leif Sundheim Susan Msolla Esther Masumba Kiddo Mtunda Sonja S. Klemsdal 《Genetic Resources and Crop Evolution》2008,55(3):397-408
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. 相似文献
2.
Stina Christensen Roland von Bothmer Gert Poulsen Lorenzo Maggioni Marianne Phillip Bente Anni Andersen Rikke Bagger Jørgensen 《Genetic Resources and Crop Evolution》2011,58(5):657-666
AFLP markers were used to characterize diversity and asses the genetic structure among 17 accessions of kale landraces, cultivars
and wild populations from Europe. The range of average gene diversity in accessions was 0.11–0.27. Several landraces showed
higher levels of diversity than the wild populations and one cultivar had the lowest diversity measures. The landraces that
were most genetically diverse were from areas where kales are known to be extensively grown, suggesting in situ conservation in these areas as a supplement to storage of seeds in gene banks. An analysis of molecular variance (AMOVA)
showed that 62% of the total variation was found within accessions. For most accessions, genetic distance was not related
to geographic distance. Similarities among accessions were probably not caused by recent gene flow since they were widely
separated geographically; more likely the relationship among them is due to seed dispersal through human interactions. Our
results indicate that a kale population found in a natural habitat in Denmark was probably not truly wild but most likely
an escape from a cultivated Danish kale that had subsequently become naturalized. 相似文献
3.
Genetic diversity among 40 accessions (Coffea canephora) of robusta coffee genepool available in India was determined in comparison with 14 representative samples from a C. canephora core collection and three accessions of C. congensis, using amplified fragment length polymorphism (AFLP) and simple sequence repeats (SSR) markers. Both these molecular approaches were able to generate unique fingerprints for each of the accessions analysed. All the 12 SSR primers used in the present study were found polymorphic, with an average of six alleles per primer pair. Comparative analysis revealed the higher amount of diversity in representatives from a core collection than in the Indian genepool. Moreover, a total of 205 polymorphic AFLP bands were scored in all the 57 accessions analysed. The genetic relationship among 57 accessions was compared on the basis of SSR and AFLP polymorphisms. Genetic similarity dendrograms showed high correlation between the two marker systems. This study clearly established the high amount of diversity present in core samples, which is not represented in Indian genepool. Furthermore, the three accessions of C. congensis did not exhibit any significant diversity from other robusta accessions supporting the school of thought that C. congensis forms a biotype of C. canephora. The potential use of SSRs and AFLP markers in genetic diversity analysis for better ex situ management and also for exploitation of diversity in breeding programmes is discussed. 相似文献
4.
DNA fingerprinting sheds light on the origin of introduced mulberry (Morus spp.) accessions in Italy
Mulberries are members of the genus Morus L., a taxonomic group showing a great genetic variability and adaptability to different environmental conditions. This study deals with the use of AFLP-based fingerprints as a tool for estimating genetic variability within as well as among three different mulberry species (i.e., M. alba L., M. latifolia Poir. and M. bombycis Koidz.). A high level of polymorphism (72.2) was found over all the 48 accessions analyzed. Genetic similarity (GS) within single Morus species ranged from 0.845 (M. bombycis) to 0.884 (M. alba) being intermediate in M. latifolia (0.869). The between-species mean genetic similarity estimates based on pair-wise AFLP marker fingerprint comparison were very similar ranging from 0.861 to 0.874. The partition of the genetic variation over the three Morus species was unexpected a proportion of the among-species genetic diversity as low as GST= 0.084 pointed out that about 92% of the total genetic diversity found among Morus accessions is due to DNA polymorphisms within a species, while only 8% of the total variation was highlighted among species. Our data indicate that some of the introduced accessions showing distinctive phenotypes, clearly differentiated from those revealed in the original habitat where they have been selected and adapted, hide an identical genotype. 相似文献
5.
To evaluate the genetic diversity and to clarify the genetic relationships of Japanese peach cultivars, we analyzed the amplified
fragment length polymorphism (AFLP) and traced the pedigree of 17 Japanese commercial peach cultivars and six traditional
accessions. Sixteen AFLP primer combinations produced a total of 837 fragments and 146 polymorphic bands with a polymorphism
percentage of 17.5%. All of the peach accessions could be identified from differences in at least 10 polymorphic bands. A
cluster analysis showed that all the Japanese commercial peach cultivars, except ‘Kiyomi’ and ‘Jichigetsuto’, formed a major
group consisting of three sub-groups. Of the six traditional accessions, four were genetically distant from the Japanese commercial
peach cultivars while two accessions from China were classified into the Japanese commercial peach cultivars group. Both the
AFLP analysis and pedigree tracing suggested that Japanese commercial peach cultivars are mainly derived from ‘Shanhai Suimitsuto’,
one of the traditional accessions from China. Although the genetic relationships revealed by AFLP were generally in agreement
with those shown by the pedigree information, some contradictions were found. Combining the AFLP results and pedigree information
can provide a better understanding of the genetic relationships of Japanese peach cultivars. 相似文献
6.
Identification and genetic relationships of kenaf (Hibiscus cannabinus L.) germplasm revealed by AFLP analysis 总被引:1,自引:1,他引:1
Zhou Cheng Bao-Rong Lu Kazuhiko Sameshima Da-Xu Fu Jia-Kuan Chen 《Genetic Resources and Crop Evolution》2004,51(4):393-401
Kenaf (Hibiscus cannabinus L.) is one of the world's most economically important fiber crops. In order to identify different varieties, and investigate its diversity and genetic relationships, twenty-three kenaf accessions and two accessions of its relative, roselle (H. sabdariffa var. altissima), were analyzed by morphological characterization and AFLP fingerprinting. It is very difficult to identify kenaf accessions based merely on morphological characters, due to their limited variation. For the AFLP study, a total of 505 polymorphic markers (out of 560) were produced by six selected AFLP primer combinations. The AFLP fingerprinting was effective in identifying all kenaf accessions included in the study. Kenaf and roselle are independent species with close relationships, and great genetic diversity was also detected among the kenaf accessions with different origins, based on the analysis of the AFLP markers. The AFLP analysis strongly supports the opinion that kenaf originated in Africa. It also demonstrated that the dissemination of kenaf was from Africa through Asia to Central and North America. 相似文献
7.
Mohammad Reza Naghavi Mohsen Mardi Seyed Mostafa Pirseyedi Mehrbanu Kazemi Payam Potki Mohammad Reza Ghaffari 《Genetic Resources and Crop Evolution》2007,54(2):237-240
Genetic diversity of 54 accessions of Aegilops tauschii from five countries was assessed using sequence-tagged microsatellites (or simple sequence repeats, SSRs) and amplified fragment
length polymorphisms (AFLPs). In the case of AFLP analysis, a total of 256 amplification products obtained, 234 of them were
polymorphic across all the 54 accessions. A total of 224 fragments were obtained from the 24 SSR primers and 219 of fragments
were polymorphic across all the genotypes screened. Based on both AFLP and SSR markers, the highest percentage of polymorphisms
were obtained in Iranian and accessions of unknown origin. The highest polymorphic information content (PIC) value was observed
for SSRs (0.82) while the highest marker index (MI) value was for AFLPs (8.5) reflecting the hyper-variability of the first
and the distinctive nature of the second system. Principal co-ordinate analysis (PCO) revealed congruent patterns of genetic
relationships for both data sets, but did not group accessions strictly according to their geographical origins. Poor correlation
was found between AFLP and SSR marker loci. This low association may be due to low number of AFLP and SSR markers. These results
show that molecular markers can help to organize the genetic variability and expose useful diversity for breeding purposes. 相似文献
8.
Fábio Luís Maciel Sergio Echeverrigaray Lee Tseng Sheng Gerald Felipe Gobbi Grazziotin 《Genetic Resources and Crop Evolution》2003,50(8):887-893
The genetic variation and relationships among 31 accessions of Phaseolus vulgaris L., and two representatives of Vigna unguiculata L., were evaluated by AFLP analysis. A total of 263 DNA fragments across all materials were scored using nine primer combinations, averaging 32 per primer. More than 95% of the amplification products showed polymorphism, indicating high variation at the DNA level among these accessions. Pair-wise genetic similarity (Jaccard's coefficient) ranged from 0.553 to 0.840, with a mean of 0.765. Twenty-three accessions (70%) clustered into three groups. A majority of the commercial cultivars (91%) clustered within a single group, whereas the landraces were distributed along all the variation. An apparent correlation with phaseolin types was detected. Results of this study suggest that Brazilian landraces truly represent the overall genetic variability of Phaseolus vulgaris, confirming the multiple origins of these materials, and their potential as a source of variation for breeding programs. 相似文献
9.
Sonia?Marghali Olivier?Panaud Fran?oise?Lamy Salma?Ghariani Aboubakry?Sarr Mohamed?Marrakchi Neila?Trifi-Farah
Amplified fragment length polymorphism (AFLP) markers were used to characterize the genetic diversity within and among natural populations and cultivars of Hedysarum coronarium. Twelve populations within Tunisia were evaluated with three AFLP primer combinations. A total of 207 reproducible bands was detected of which 178 (86%) were polymorphic. The great discriminative power of AFLP markers and their ability to represent genetic relationships among Hedysarum plants was demonstrated. Genetic diversity within and among populations was assessed through Principal Component Analysis (PCA) and cluster analysis by using the Neighbor-joining clustering algorithm. AFLP technology has provided evidence of a high degree of intra- and inter-population genetic diversity in H. coronarium. AFLP banding patterns provided molecular markers correlated with the plants’ geotropism. In addition, AFLP markers can differentiate wild accessions from cultivars. Moreover, geographical origins did not correspond to population clustering. 相似文献
10.
Nature of taro (Colocasia esculenta (L.) Schott) genetic diversity prevalent in a Pacific Ocean island, Vanua Lava, Vanuatu 总被引:1,自引:0,他引:1
S. Caillon J. Quero-Garcia J.-P. Lescure V. Lebot 《Genetic Resources and Crop Evolution》2006,53(6):1273-1289
Taro (Colocasia esculenta (L.) Schott), cultivated in Vêtuboso, a village of northern Vanuatu, Melanesia, was surveyed to: (1) assess the extent of morphological and molecular variation being maintained by growers at the village level and, (2) compare this diversity with the diversity found in the crops in Vanuatu. Ethnobotanical data were combined with AFLP analysis to elucidate possible sources of variation. Folk assessment of variation is based on: (a) morphological characteristics (11 characters), (b) names and (c) classification according to habitat, uses, origin and agronomic adaptation. This 3-fold approach allowed growers to differentiate 96 morphotypes, all of which are given distinct vernacular names. AFLP fingerprints successfully differentiated all these 96 morphotypes which do not present a significant intra-clonal variation. But genetic results showed no clear groupings according to geographic origin or habitat of morphotypes and stated that the diversity found within the village was comparable with the overall diversity found in Vanuatu. Local nomenclature and stories associated with each cultivar suggested three sources of diversity: introductions (38%), somatic mutations (15%) and sexual recombinations (48%). AFLP results confirm folk beliefs about origin at least for three pairs of mutants. The 11 so-called wild forms analysed by AFLP were suggested to be feral, escapes from domestication. A dynamic in situ conservation strategy (DISC), favouring a broadening of the national genetic base, was discussed for taro. 相似文献
11.
Evaluation of genetic diversity of bread wheat landraces from Pakistan by AFLP and implications for a future collection strategy 总被引:1,自引:0,他引:1
Ryoko Hirano Akira Kikuchi Makoto Kawase Kazuo N. Watanabe 《Genetic Resources and Crop Evolution》2008,55(7):1007-1015
We used amplified-fragment-length polymorphism (AFLP) markers to evaluate genetic variation in a set of bread wheat (Triticum aestivum L.) landraces and improved materials. Landraces collected from different geographic and agro-ecological zones in Pakistan
in 1987, 1989 and 1991 were separated into two groups based on their geographic origins: northern (Himalaya) and south-western
(Balochistan) Pakistan. Six AFLP primer combinations detected 453 AFLP markers in the 43 landrace accessions and four high-yield
varieties (HYVs). Of these, 225 (49.67%) were rare (shared with < 5% of all accessions). Among these rare alleles, 23 (10.22%)
were common in the Himalaya (shared with > 10% of accessions collected there) but were not found in Balochistan. We conclude
that there is a higher probability of collecting rare alleles at overall, but which are in contrast locally common ones in
the Himalayan region. Gene diversity was 0.17 in the Himalayan group and 0.15 in the Balochistan group. Considerable genetic
variability was found in both groups. Accessions from different agro-ecological zones were indistinguishable by cluster analysis,
indicating intensive seed trading within the country. Cluster analysis indicated that the landraces and the HYVs are genetically
distinct; suggesting that genetic erosion of wheat landraces has been unlikely taken in place. This study provides an example
of how analysis of existing materials and data, can serve as a basis for future collection planning and conservation policies. 相似文献
12.
Germplasm conserved as seeds in genebanks requires regular regeneration. In this process, selection and genetic drift may cause loss of genetic diversity from accessions. In the case of selfing crops, separation of distinct lines into different accessions may be an efficient strategy to avoid these negative effects. In order to evaluate the applicability of this method for collection management, knowledge about the level of intra-accession genetic diversity is required. By means of AFLP analysis intra-accession variation was investigated in two cultivars, two landraces and two wild populations of ex situ conserved barley germplasm. In the total sample of 216 individuals analysed (36 per accession), 22 genotypes were observed based on 104 polymorphic loci. The number of genotypes detected ranged from 1 to 3 per accession, except for a Nepalese landrace that revealed 12 genotypes. An UPGMA cluster analysis grouped the genotypes unambiguously into the accession they belonged to and genotypes within accessions were generally found to be closely related. In order to determine the repeatability of the results obtained, 11 individuals belonging to 4 genotypes from the Nepalese landrace were scored for a second set of AFLP markers. Matrices of genetic distances calculated for the two AFLP datasets were found to be highly correlated (r = 0.9346, P < 0.001). Separation of genotypes into different accessions was considered a relevant option only for the Nepalese landrace. Analysis of molecular variance indicated that this accession could be well divided into 8 distinct lines. Further implications of the results for genebank practices are discussed. 相似文献
13.
Ahmed Mliki Jack E. Staub Sun Zhangyong Abdelwahed Ghorbel 《Genetic Resources and Crop Evolution》2003,50(5):461-468
Genetic diversity among 26 cucumber (Cucumis sativus L. var. sativus) accessions from five African countries [Algeria (1), Egypt (21), Ethiopia (2), Kenya (1), and Libya (1)] present in the U.S. National Plant Germplasm System (NPGS) were examined by assessing variation at 71 polymorphic random amplified polymorphic DNA (RAPD) loci. Genetic distances (GD; simple matching coefficient) were estimated among these African accessions and a reference array (RA) of 21 accessions representative of the genetic variation in cucumber. GD among African accessions ranged between 0.41 and 0.97. GD among accessions in the reference array ranged between 0.36 and 0.88. Multivariate analysis identified three distinct groupings (1–3) of African accessions; Group 1 contained 21 accessions (Egypt, Ethiopia and Libya), Group 2 consisted of two accessions (Kenya, Algeria), and Group 3 possessed three accessions (Egypt). These groupings were distinct from each other (P > 0.001). Accessions in Group 1 differed genetically from all other accessions examined (P > 0.01), and accessions in Groups 2 and 3 were uniquely associated with several RA accessions. While GD among accessions in Group 1 ranged between 0.52 and 0.90, distances among Group 2 accessions varied between 0.93 and 0.97. The GD between the two accessions in Group 3 was 0.65. An accession from Syria (PI 181874) and from one Turkey (PI 199383) were genetically more similar to accessions in Group 1 than to other accessions in the RA. Likewise, accessions in Group 2 were genetically similar to two RA accessions from China and a European glasshouse cucumber line, and Group 3 accessions showed genetic affinities with the U.S. market class cultivar Dasher II. Data suggest that some Egyptian accessions (Group 1) possess unique genetic variation, that this germplasm has potential for broadening the genetic base of commerical cucumber, and that further collection of African germplasm is likely to enhance genetic diversity of cucumber in NPGS. 相似文献
14.
Randomly amplified polymorphic DNA (RAPD) analysis was employed to assess genetic divergence among 29 neem accessions collected from two agro-ecological regions of India (11 agro-climatic sub-zones), which cover three states, Punjab, Haryana and Rajasthan. Out of 24, 10-mer random primers used for studying genetic divergence, 14 were polymorphic, generating a total of 73 amplification products with an average of 5.21 products per polymorphic primer and estimated gene diversity of 0.49. Genetic relationships among accessions were evaluated by generating a similarity matrix based on Jaccard’s coefficient, ranging from 0.70 to 0.96. The phenetic dendrogram generated by UPGMA analysis grouped accessions into five clusters. RAPD performed within accessions (individual seedlings collected from the same mother plant) showed no variation indicating homogeneous population within accessions. Primers OPA-18, OPC-08 and OPI-03 were found most informative based on their resolving power. The degree of genetic variation detected among the 29 accessions with RAPD analysis suggests that RAPD can be used for studying genetic diversity in neem. The study also demonstrated that neem germplasm collected from northwestern plains of India shows no eco-geographical isolation based on sub-zones because accessions collected from different sub-regions are grouping together in the genetic tree. 相似文献
15.
A. Kolodinska Brantestam R. von Bothmer C. Dayteg I. Rashal S. Tuvesson J. Weibull 《Genetic Resources and Crop Evolution》2007,54(4):749-758
To examine changes in the level of and pattern in variability in 197 Nordic and Baltic spring barley cultivars over time we
used 21 mapped barley simple sequence repeats (SSRs). A total number of 191 alleles were found from 22 SSR loci. The number
of alleles per locus ranged from 2 to 23, with average of 8.63 107 alleles were rare (frequency <0.05) among the cultivars
and only one allele was frequently observed (frequency >0.95). The gene diversity between loci in Nordic and Baltic material
varied between 0.033 and 0.891. Average gene diversity was 0.623. The SSR data separated two-rowed and six-rowed cultivars.
According to analysis of molecular variance (AMOVA) differentiation in two-rowed vs six-rowed accounted for 23.6% of the total
variation. Overall no significant decrease of average gene diversity over time could be found. However, differences were observed
when spring barleys from northern (north of ∼58°) and southern (south of ∼58°) parts of the Nordic and Baltic area were compared.
For the southern ecogeographical region significant decrease of genetic diversity was observed in the middle of the 20th century,
whereas no significant changes in the northern part were found. We found larger differentiation between modern and old cultivars
in the South compared to the ones in North parts of the region. The magnitude of changes in genetic diversity differed also
with the country of origin. Danish cultivars had a significant decrease in diversity in the middle of century, whereas changes
in Finland, Norway and Sweden were not significant. 相似文献
16.
Tiny Motlhaodi Mulatu Geleta Stephen Chite Moneim Fatih Rodomiro Ortiz Tomas Bryngelsson 《Genetic Resources and Crop Evolution》2017,64(3):599-610
Cultivated sorghum [Sorghum bicolor (L.) Moench] is an important food security crop in the semi-arid regions of the world including Asia and Africa. Its genetic diversity is contained mostly in traditional varieties and modern cultivars used by farmers. In this study, agro-morphological traits and molecular markers were used to assess genetic diversity in 22 accessions of cultivated sorghum from five countries (Botswana, Namibia, Swaziland, Zambia and Zimbabwe) in the Southern African Development Community (SADC) region. The study revealed a significant variation among 22 accessions in both qualitative and quantitative morphological traits, indicating the accessions’ promising potential as breeding material. For molecular analysis, 11 microsatellite primer-pairs were used, and generated a total of 70 alleles across 20 accessions. Analysis of molecular variance revealed a high level of genetic variation; 67 % among the accessions and 10 % among the five countries. The patterns of genetic diversity and the relationships observed in this study should provide insights for genetic resource conservation and utilization of sorghum germplasm in the SADC region. 相似文献
17.
K. Persson R. von Bothmer M. Gullord E. Gunnarsson 《Genetic Resources and Crop Evolution》2006,53(4):857-866
Phenotypic diversity for agronomic characteristics was determined in an experiment with 29 landraces and 14 improved varieties
of rye from the Nordic area, Germany and Poland. The accessions were scored for 12 characters. Effects of the location, year,
type, and country of origin for landraces were investigated with analysis of variance. Phenotypic variations for the traits
were estimated using the Shannon–Weaver diversity index. The genetic variation was high, with an average of H 0 = 0.566. The landraces from Norway, Sweden and Finland showed the highest variation, whereas the improved varieties had the
lowest. The German material also had low variation but the status of this material is uncertain. The genetic diversity showed
that 70% of the variation was found within the accessions. A cluster analysis was carried out to identify the relationship
between the accessions. The material grouped into eight clusters, where clusters I to V included landraces from Sweden, Finland
and Norway, except for cluster III, which included one improved variety from Denmark. Cluster VI comprised a single Swedish
landrace from Gotland. Most of the improved varieties were in cluster VII and the last cluster contained accessions from Germany
and Sweden. 相似文献
18.
A total of 242 accessions of common wheat (Triticum aestivum L.) released in China since the 1940s were evaluated with AFLP (amplified fragment length polymorphism) technique. Genetic diversity was analyzed using five pairs of polymorphic primer combinations with 245 polymorphic bands. The highest genetic diversity was found in the accessions of the 1950s, and in the next place was that in the 1940s. The genetic diversity began to descend in the 1960s, and fell to the lowest in the 1970s. After that, the genetic diversity came back to some extent in the 1980s, however, it became much lower in the 1990s compared with that in the 1940–1950s. Landraces and introduced accessions from foreign countries showed greater genetic diversity in comparison to improved varieties. In addition, greater genetic diversity was observed in winter wheat. It was emphasized that great attention should be paid on further exploration of genetic diversity in wheat breeding program. 相似文献
19.
More than 100?years ago, before the rediscovery of Mendel’s laws of inheritance, Nazareno Strampelli started a deliberate crossing programme among Italian and foreign bread wheat genotypes that led to the constitution of over 100 varieties and allowed Italy to significantly increase wheat production. Several varieties enjoyed worldwide popularity and were instrumental in the success of many other breeding programmes. To better understand the reasons of these accomplishments, 84 accessions, representing 50 Strampelli varieties, were characterized for glutenin storage proteins and AFLP patterns, in order to confirm their identification and to assess their genetic diversity. The molecular markers analysis confirmed the correct attribution of most accessions and highlighted the broad genetic variation existing among Stampelli’s varieties. Some genotypes, deemed incompatible with the available pedigree data, were removed from the final analysis. A limited within-variety diversity among genotypes was probably due to incomplete homogeneity and stability of Strampelli materials, but also to the use of heterogeneous local populations as parents. 相似文献
20.
Gerard Allan Amber Williams Pablo D. Rabinowicz Agnes P. Chan Jacques Ravel Paul Keim 《Genetic Resources and Crop Evolution》2008,55(3):365-378
Worldwide genetic diversity in 200 individuals comprising 41 castor bean accessions was assessed using amplified fragment
polymorphisms (AFLPs) and simple sequence repeats (SSRs). We found that, despite surveying five continents and 35 countries,
genetic diversity in castor bean germplasm is relatively low (overall H
e = 0.126 for AFLPs and 0.188 for SSRs) compared to estimates of genetic diversity in other plant species. Our data also show
no geographic structuring of genotypes across continents or countries within continents. An assessment of the congruence between
AFLP and SSRs indicates a low correlation (R
2 = 0.19) between the two data sets, but each marker class nonetheless shows similar patterns of low-genetic diversity and
a lack of geographic structure. Our data do suggest that SSRs yield a higher percentage of polymorphic loci, higher heterozyosity
and a greater range of genetic distances, and are therefore more informative than are AFLPs on a locus-by-locus basis. Based
on comparisons with numerous other plant species, we suggest that the lower genetic variation in this worldwide collection
may be due to one or more factors including: sampling strategies that have not captured the full extent of genetic variation
in the species; artifactual variation due to long-term germplasm storage and seed regeneration; or intense selection followed
by domestic cultivation of a limited number of castor bean genotypes, which are widely propagated for their horticultural
and agro-economic value. 相似文献