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1.
Edward J. Boza Brian M. Irish Alan W. Meerow Cecile L. Tondo Orlando A. Rodríguez Marisol Ventura-López Jaime A. Gómez J. Michael Moore Dapeng Zhang Juan Carlos Motamayor Raymond J. Schnell 《Genetic Resources and Crop Evolution》2013,60(2):605-619
Cacao (Theobroma cacao L.) is a significant agricultural commodity in the Dominican Republic, which ranks 11th in the world for cacao exports. To estimate genetic diversity, determine genetic identity, and identify any labeling errors, 14 SSR markers were employed to fingerprint 955 trees among cacao germplasm accessions and local farmer selections (LFS). Comparisons of homonymous plants across plots revealed a significant misidentification rate estimated to be 40.9 % for germplasm accessions and 17.4 % for LFS. The 14 SSRs amplified a total of 117 alleles with a mean allelic richness of 8.36 alleles per locus and average polymorphism information content (PIC) value of 0.67 for the germplasm collection. Similar levels of variation were detected among the LFS where a total of 113 alleles were amplified with a mean of 8.07 alleles per locus and PIC of 0.57. The observed heterozygosity (Hobs) was 0.67 for the germplasm collection and 0.60 for LFS. Based on population structure analysis 43.9 % of the germplasm accessions and 72.1 % of the LFS are predominantly of the Amelonado ancestry. Among these Amelonado, 51.7 % for the germplasm collection and 50.6 % for LFS corresponded to Trinitario hybrid lineage. Criollo ancestry was found in 7.6 and 9.5 % of the germplasm accessions and LFS, respectively. The Contamana, Nacional, and Iquitos backgrounds were also observed in both populations, but the Curaray background was only detected in the germplasm accessions. No Purús or Guiana ancestry was found in either of the populations. Overall, significant genetic diversity, which could be exploited in the Dominican Republic breeding and selection programs, was identified among the germplasm accessions and LFS. 相似文献
2.
3.
The International Cocoa Genebank, Trinidad (ICG,T) contains about 2000 cacao (Theobroma cacao L.) accessions. The purpose of the collection is to provide a source of genes for the genetic improvement of cacao through
breeding. In fulfilling this objective, it is imperative that this collection be evaluated to identify major sources of genes
for the genetic improvement of important agronomic–economic traits. In this study, 816 cacao accessions were evaluated for
resistance to Phytophthora pod rot (black pod disease), which causes enormous loss of yield in cocoa production throughout the world.The study identifies
promising resistant genotypes that could be exploited in cacao breeding programmes. It further compares the levels of resistance
to Phytophthora pod rot among two cacao types (wild and cultivated types), three major groups (Forastero, Trinitario and Refractario) and
11 accession groups (B, AM, CL, ICS, IMC, JA, LP, MOQ, NA, PA and TRD) . The distribution of scores for the 816 accessions
showed skewness towards the susceptible end of the disease rating scale, indicating that a large proportion (68.9%) of the
sample was susceptible (disease rating 6–8) to Phytophthora pod rot. However, 12.9% of the sample population was found to be resistant (disease rating 1–3) and 18.2% moderately resistant
(disease rating 4–5). Significant differences were observed between the wild and cultivated accessions and among the Forastero,
Refractario and Trinitario groups. Marked differences were also observed among 11 accession groups, each of which was represented
by at least 20 genotypes. Higher proportions of resistant (17.7%) and moderately resistant (22.6%) genotypes were observed
in the wild accessions than in the cultivated varieties (9.4% resistant and 14.4% moderately resistant). The Forastero group,
consisting of many wild accessions, was found to contain more resistant (18.0%) and moderately resistant (23.1%) genotypes
than either the Trinitario (4.8% resistant and 13.6% moderately resistant) or Refractario (11.3% resistant and 15.4% moderately
resistant). Among 11 accession groups, the largest percentage of resistant (24.2%) and moderately resistant (28.8%) genotypes
were found in the PA (Forastero). Different accession groups had varying proportions of resistant and moderately resistant
genotypes. This is not unexpected in an out-breeding crop such as cacao with a high level of heterogeneity. This finding reinforces
the idea of a pre-breeding programme (germplasm enhancement) to accumulate resistance genes over several populations as a
strategy for improving the genetic base of resistance in national cacao breeding programmes. One hundred and five promising
resistant genotypes were identified among the 816 accessions evaluated. These accessions are potential sources of resistance
genes for the development of high-yielding resistant varieties in cacao. 相似文献
4.
Yosuke Kuroda Norihiko Tomooka Akito Kaga S. M. S. W. Wanigadeva Duncan A. Vaughan 《Genetic Resources and Crop Evolution》2009,56(8):1045-1055
Wild soybeans, Glycine soja, are a source of genetic variation to improve soybeans. To improve the efficiency evaluation of conserved germplasm a core
or mini-core collection approach that maximizes allelic diversity in a proportion of the whole collection has frequently been
advocated. The genetic diversity of a wild soybean collection (1,305 accessions) plus Japanese cultivated soybeans (53 accessions)
were analyzed at 20 SSR marker loci. Higher levels of allelic diversity were found in wild soybeans (28 alleles per locus)
than Japanese cultivated soybean (five alleles per locus). The genetic distance between wild soybeans from different regions
reflected their proximity. Accessions from Russia consisted of a diverse array of alleles resulting in accessions being spread
further apart in a PCA plot than accessions from other regions. Accessions of wild soybean from Korea included many rare alleles
and thus had a high representation in the core collection. The two core collections developed here, traditional and mini,
consisted of 192 accessions with 97% of the allelic diversity (14% of the whole collection) and 53 accessions with 62.4% of
the allelic diversity (5% of the whole collection), respectively. 相似文献
5.
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
6.
Mohammad R. Sabzalian Aghafakhr Mirlohi Ghodratollah Saeidi Mohammad T. Rabbani 《Genetic Resources and Crop Evolution》2009,56(8):1057-1064
Wild species of safflower, Carthamus oxyacanthus Bieb., is highly crossable with cultivated species, C. tinctorius L. and could be directly exploited in broadening safflower gene pool and improving the crop for biotic and abiotic stress
environments. In this study, genetic diversity among accessions of C. oxyacanthus and their relationships with cultivated safflower were evaluated using agro-morphological traits and polymorphic inter-simple
sequence repeats (ISSR) markers. Significant variation was observed among accessions particularly for seeds per capitulum,
seed yield per plant, harvest index and capitula per plant. Cluster analysis based on agro-morphological traits classified
the wild accessions in two groups according to their geographical regions, and separated them from the cultivated genotypes.
ISSR marker also revealed a high genetic variation among the accessions, and cluster analysis based on this marker divided
genotypes into four groups, with cultivated ones in a separate clade. Genetic variation observed among the wild safflower
germplasm at the DNA level was higher than the agro-morphological traits, indicating that ISSR is an effective marker system
for detecting diversity among safflower genotypes and their genetic relationships. Accessions of C. oxyacanthus with high genetic relationship to cultivated species could be used for interspecific hybridization in breeding programs of
safflower. 相似文献
7.
Michael Dossett Nahla V. Bassil Kim S. Lewers Chad E. Finn 《Genetic Resources and Crop Evolution》2012,59(8):1849-1865
Breeding progress in black raspberry (Rubus occidentalis L.) has been limited by a lack of genetic diversity in elite germplasm. Black raspberry cultivars have been noted for showing very few phenotypic differences and seedlings from crosses between cultivars for a lack of segregation for important traits. Despite these challenges, little molecular work has been done to explore genetic diversity and relationships in wild and cultivated black raspberry germplasm. Microsatellite, or simple sequence repeat (SSR), markers are highly polymorphic codominant markers useful for studying genetic diversity, population genetics, genetic fingerprinting and other applications. We examined genetic diversity in 148 wild and cultivated black raspberry accessions using 21 polymorphic SSR markers. Black raspberry cultivars clustered tightly and showed higher than expected heterozygosity while that of wild accessions was low. Relationships between wild black raspberry accessions were poorly resolved and regional clusters were mostly absent from our analysis. Our results indicated that wild black raspberry germplasm is a relatively untapped resource available for future breeding. 相似文献
8.
Worapa Seehalak Norihiko Tomooka Aree Waranyuwat Piyada Thipyapong Paisan Laosuwan Akito Kaga Duncan A. Vaughan 《Genetic Resources and Crop Evolution》2006,53(5):1043-1059
Thailand is a center of diversity for section Angulares of the Asian Vigna (genus Vigna subgenus Ceratotropis) and 4 Vigna species are cultivated in Thailand. Using newly collected wild and cultivated germplasm of Vigna from Thailand and outgroup accessions AFLP analysis was conducted to clarify genetic diversity and relationships. The results
suggest that cultivated V. umbellata and V. mungo evolved from wild relatives in a single domestication event. Vigna umbellata is poorly differentiated from its wild and weedy relatives compared to V. mungo. Results suggest northern Thailand and the neighboring Shan state, Myanmar, is the probable center of domestication for V. umbellata as wild accessions from this area and cultivated rice bean from a wide area in Asia are not greatly diverged. Vigna minima, V. tenuicaulis and V. exilis accessions in Thailand are well differentiated with considerable intra-specific variation. Vigna hirtella consists of two well differentiated subgroups, suggesting taxonomic revision may be necessary. Close genetic relationships
between V. radiata and V. grandiflora, and between V. mungo and V. trinervia are confirmed. Naturally growing V. mungo populations in northern Thailand appear to be true wild species as they are well differentiated from Indian wild and Thai
cultivated populations. The origin of naturally growing cowpea in Thailand needs to be further studied using a more comprehensive
set of materials. This study clarifies inter and intra-specific genetic diversity and inter species relationships of Thai
Vigna species. 相似文献
9.
To improve understanding of diversity of Lablab purpureus and establish relationships among 103 germplasm accessions collected from diverse geographic origins, amplified fragment
length polymorphism markers were used. Four primer sets selected out of 16 produced 289 clear, repeatable polymorphisms. UPGMA
analysis of similarity data clustered the accessions according to their subspecific taxonomic organization, i.e., subsp. purpureus and subsp. uncinatus, as well as to cultivated and wild forms. The well-represented landraces from Africa and Asia, belonging predominantly to
subsp. purpureus, displayed moderate genetic diversity. Wild forms from Africa showed far greater levels of diversity that would justify taxonomic
re-assessment of the wild subsp. uncinatus. The molecular analysis identified forms that were collected in the wild in India but were genetically placed intermediate
between wild and cultivated forms. As these plant types did not exist among the African accessions, it is suggested that they
might represent escapes from early attempts of domestication. These results support the suggested pathway of domestication
and distribution of L. purpureus from Africa to Asia. Additional members to a previously published core collection of the species are proposed. 相似文献
10.
Alex Beharav Roi Ben-David Ivana Doležalová Aleš Lebeda 《Genetic Resources and Crop Evolution》2010,57(5):679-686
The wild lettuce, Lactuca aculeata Boiss. et Ky., is closely related and fully interfertile with cultivated lettuce, Lactuca sativa L. Altogether, 155 accessions of this wild species, which is rare conserved within the world’s germplasm collections, were
collected from 12 localities throughout northeastern Israel. Ten of these localities represent different sites across the
Golan Heights, while two, high-density populations were suprisingly found at the Hula Plain (first report of this species
in this region). Lactuca aculeata was recorded at various elevations (222–968 m a.s.l.) and habitats. The taxonomic status of 30 L. aculeata accessions was morphologically validated during ex situ seed regeneration of 31 random accessions representing all 12 localities. Characterization of 12 traits showed that the Israeli
populations of L. aculeata do not exhibit broad morphological variability, but more great levels of variation were obtained for developmental traits.
Relatively little variability was observed in the morphology of cauline leaves or in the distribution of anthocyanin pigmentation
in bracteae. In two cases, L. aculeata plants lacked trichomes in the inflorescence, a typical feature in the majority of plants. These unique collections of wild
lettuce may carry novel sources of genetic variation for a wide range of traits and, thus, should be of interest for careful
evaluation and exploitation in lettuce breeding. 相似文献
11.
X. Cadima Fuentes R. van Treuren R. Hoekstra R. G. van den Berg M. S. M. Sosef 《Genetic Resources and Crop Evolution》2017,64(2):331-344
Potato wild relatives are important sources of novel variation for the genetic improvement of the cultivated potato. Consequently, many natural populations have been sampled and were deposited as accessions in gene banks around the world. Here we investigate to what extent the genetic variation of Bolivian wild potato species is maintained under gene bank conditions and how this diversity relates to that of current in situ populations. For this purpose, materials from seven potato species were screened for microsatellite variation. Genetic changes between different generations of ex situ germplasm were not observed for Solanum leptophyes and S. megistacrolobum, but were detected for S. neocardenasii and S. okadae, while each of the species S. acaule, S. avilesii and S. berthaultii showed stability in some cases and genetic change in others. The observed changes were ascribed to genetic drift and contamination resulting from human error during regeneration. Re-collected populations of six of the studied species showed highly significant genetic differences with the ex situ accessions that, apart from changes during ex situ maintenance, are most likely to be attributed to sampling effects during collecting and in situ genetic changes over time. The implications of the results for ex situ and in situ conservation strategies of wild potato species are discussed. 相似文献
12.
Pedro Talhinhas José Leitão João Neves-Martins 《Genetic Resources and Crop Evolution》2006,53(3):563-578
Lupinus angustifolius L. is a Mediterranean species, domesticated in the 20th century, representing an important grain legume crop in Australia
and other countries. This work is focused on the collection of wild germplasm and on the characterisation of morphological
and molecular diversity of germplasm accessions. It reports the collection of 81 wild L. angustifolius accessions from the South and Centre of Portugal, available at the ‘Instituto Superior de Agronomia Gene Bank’, with subsequent
morphological and molecular characterisation of a selection of these and other accessions. A multivariate analysis of morphological
traits on 88 L. angustifolius accessions (including 59 wild Portuguese accessions, 15 cultivars and 14 breeding lines) showed a cline of variation on wild
germplasm, with plants from Southern Portugal characterised by earlier flowering, higher vegetative development and larger
seeds. AFLP and ISSR molecular markers grouped modern cultivars as sub-clusters within the wider diversity of wild germplasm,
revealing the narrow pool of genetic diversity on which domesticated accessions are based. The importance of preserving, characterising
and using wild genetic resources for L. angustifolius crop improvement is outlined by the results obtained. 相似文献
13.
Taro [Colocasia esculenta (L.) Schott] germplasm accessions collected from different parts of India were subjected to RAPD (Random Amplified Polymorphic DNA) analysis to assess the genetic diversity prevalent and also to test the genetic basis of morphotypic classification. Thirteen random decamer primers out of the 22 tested were used to analyse 32 taro accessions belonging to 28 morphotypes. Three out of these thirteen primers analysed showed 100 per cent polymorphism. Per cent polymorphism varied from 60 to 100 among the polymorphic primers. High genetic diversity was revealed as the similarity coefficient values ranged from 0.50 to 0.98. No two accessions analysed in the present study showed a similarity coefficient value of one thereby indicating their distinctness and presence of high genetic diversity in Indian taro germplasm. Dendrogram obtained from UPGMA analysis grouped 32 accessions in four clusters and three accessions were placed as outliers. Clustering pattern did not show any strict relationship with geographical distribution, morphotype classification and genotypic diversity. Further, accessions classified, as belonging to the same morphotypic group did not always cluster together. Presence of a very close genepool of the wild, weedy and cultivated forms with extreme levels of phenotypic and genotypic variation is suggested as the reason for high genetic diversity reported. Usefulness of DNA markers such as RAPD in characterising and assessing the genetic diversity in Indian taro germplasm is hereby demonstrated. 相似文献
14.
L. Riahi N. Zoghlami K. El-Heit V. Laucou L. Le Cunff J. M. Boursiquot T. Lacombe A. Mliki A. Ghorbel P. This 《Genetic Resources and Crop Evolution》2010,57(2):255-272
Three gene pools representative of Vitis vinifera L. subsp. vinifera (=subsp. sativa Beger) growing in the Maghreb regions (North Africa) from Tunisia (44), Algeria (31) and Morocco (18) and 16 wild grape accessions
(Vitis vinifera L. subsp. sylvestris (Gmelin) Beger) from Tunisia were analysed for genetic diversity and differentiation at twenty nuclear microsatellites markers
distributed throughout the 19 grape chromosomes. 203 alleles with a mean number of 10.15 alleles per locus were observed in
a total of 109 accessions. Genetic diversities were high in all populations with values ranging from 0.6775 (Moroccan cultivars)
to 0.7254 (Tunisian cultivars). F
st pairwise values between cultivated grapevine populations were low but found to be significantly different from zero. High
F
st pairwise values were shown between wild and cultivated compartments. Two parent offspring relationships, two synonyms and
two clones of the same cultivar were detected. The rate of gene flow caused by vegetative dissemination of cultivated grapevine
plants was not sufficient to genetically homogenise the pools of cultivars grown in different regions. The Neighbour Joining
cluster analysis showed a clear separation according to geographical origins for the cultivated grapevines gene pools and
revealed a high dissimilarity between cultivated and wild grapevine. However, three cultivars (Plant d’Ouchtata 1, Plant de
Tabarka 3 and Plant d’Ouchtata 3) are very close to wild accessions and may result from a hybridisation between cultivated
and wild accessions. The high level of differentiation between cultivated and wild accessions indicates that the cultivated
accessions do not derive directly from local wild populations but could mostly correspond to imported materials introduced
from others regions during historical times or derived from crossing between them. 相似文献
15.
Toan Duc Pham Tri Minh Bui Gun Werlemark Tuyen Cach Bui Arnulf Merker Anders S. Carlsson 《Genetic Resources and Crop Evolution》2009,56(5):679-690
Sesame (Sesamum indicum L.) is a traditional oil crop cultivated throughout South East Asia. To estimate the genetic diversity of this crop in parts
at the region, 22 sesame accessions collected in Vietnam and Cambodia were analyzed using 10 RAPD markers. The 10 primers
generated 107 amplification products of which 88 were polymorphic fragments (83%). Genetic diversity of all populations was
Ht = 0.34 when estimated by Nei’s genetic diversity and species diversity was H′sp = 0.513 when estimated by Shannon diversity index. Genetic distance ranged from 0.03 to 0.43, with a mean genetic distance
of 0.23. The unweighted pair group method with arithmetic averages (UPGMA) cluster analysis for the 22 accessions divided
the material in four groups. The dendrogram revealed a clear division among the sesame accessions based on their geographical
region. Interestingly, some geographically distant accessions clustered in the same group, which might indicate the human
factor involved in the spreading of sesame varieties. The high level of polymorphism shown suggests that RAPD techniques can
also be useful for the selection of parents in sesame (Sesamum indicum L.) breeding program and for cultivar differentiation. 相似文献
16.
Brigitte L. Maass Oliver Robotham Mark A. Chapman 《Genetic Resources and Crop Evolution》2017,64(6):1221-1230
Studying molecular genetic relationships can substantially contribute to the understanding of the pathways of domestication of a species. Although an increasing number of molecular genetic studies have been performed on Lablab purpureus (hyacinth bean), many covered germplasm of restricted geographic origin or limited intra-specific systematic position. Integrating the molecular diversity found with phenotypic or morpho-agronomic diversity is also deficient. This investigation combines findings of eight molecular genetic studies that include about 400 accessions of both wild and cultivated germplasm, thus providing the largest assessment of diversity in Lablab purpureus to date. In particular, results from a recent molecular investigation (Robotham and Chapman 2015) are revisited and reinterpreted by integrating them with known phenotypic diversity. Wild accessions clearly fall into two types, with characteristic pods—2-seeded and 4-seeded. The large majority of cultivated types are more closely related to 4-seeded pod-types. Certain cultivated 2-seeded pod-type accessions from Ethiopia are genetically closer to wild 2-seeded pod-types. These two major phenotypes are reflected in two chloroplast DNA haplotypes A and B. Hence, two domestication events appear to exist in L. purpureus based on this combined data. No other geographic patterns of diversity, which might assist to trace the dispersal of L. purpureus, were found as cultivated accessions predominantly fell into 2-3 major groups. In all studies, the greatest genetic diversity was found in Africa, making Ethiopia one of the probable centers of domestication. 相似文献
17.
Mauricio Parra-Quijano Sauris Panda Nohra Rodríguez Elena Torres 《Genetic Resources and Crop Evolution》2012,59(1):49-66
Ullucus tuberosus (common name ‘ulluco’) is a popular tuber crop of Andean highlands. Until now attention has been focused on ulluco from Bolivia,
Peru and Ecuador, but little is known about its diversity in Colombia. Thirty-six accessions of cultivated ulluco preserved
in the Gene Bank of the Universidad Nacional de Colombia were studied to assess the genetic diversity and spatial genetic
structure of Colombian ulluco. We used morphological characters, molecular markers (total proteins, isozymes and RAPDs) and
ploidy level. High morphological variability, especially for tuber shape and colour characters, was found. Eight accessions
from north-east Colombian Andes showed some typical character-states of wild ulluco, suggesting that they could be partially
domesticated forms. Genetic analysis using RAPD markers indicated that these accessions were very similar to other cultivated
ullucos belonging to the same region. The regional structure observed in isozyme and RAPD dendrograms was confirmed by AMOVA
results (52.6% among-region variation) and the spatial correlogram, showing the presence of two gene pools of ulluco in Colombia.
Our results and the accumulated data suggest that ulluco was introduced to Colombia at least two times. Initially, semi-domesticated
forms would have come from the central Andes to north-east Colombian Andes, where the native inhabitants would have completed
the domestication process. Again, fully domesticated ullucos might have been introduced to south-west Colombian Andes. 相似文献
18.
Kun Ji Dapeng Zhang Lambert A. Motilal Michel Boccara Philippe Lachenaud Lyndel W. Meinhardt 《Genetic Resources and Crop Evolution》2013,60(2):441-453
Cacao (Theobroma cacao L.) is the main source for chocolate with an annual production of four million tons worldwide. This Neotropical tree crop was domesticated in Mesoamerica as far back as 3,000 years ago. Knowledge of genetic diversity and population structure in farmer varieties of cacao in the center of domestication is essential for sustainable production of fine-flavored cacao beans and contributes to in situ/on-farm conservation of farmer varieties. Based on 70 single nucleotide polymorphism markers, we analyzed 84 fine-flavored farmer varieties collected from traditional cacao farms in Honduras and Nicaragua. The study also included 31 clones from the international cacao collections to serve as references. The SNP based multilocus matching identified six synonymous groups, including 14 Criollo and two Amelonado varieties. A moderately high level of genetic diversity was observed in these farmer varieties, indicating the possibility to further explore intra-population variation and breed for fine-flavored cocoa. Multivariate analysis showed clustering of the 84 farmer accessions in five genetic groups: ancient Criollo, Amelonado, Trinitario (including Nicaragua Trinitario and Honduras Trinitario) and Upper Amazon Forastero (only one accession). The Honduras Trinitario differed from the Nicaragua Trinitario group. The clustering results largely supported the perceived classification of cacao by local farmers and researchers, which was mainly based on morphological traits. However, the well known traditional variety “Indio” in this region was identified as synonymous with Amelonado. Parentage analysis showed that the variety “Indio” (or Amelonado) contributed more to the Trinitario type farmer varieties, whereas ancient Criollo had less influence. The present study demonstrates the efficacy of using a small set of SNP makers for cacao germplasm characterization, and further depicts the diverse origins and parentage in farmer varieties from Mesoamerica. This information thus will be highly useful for conservation and utilization of cacao germplasm from this region. 相似文献
19.
Jean-Marie Prosperi Eric Jenczewski Michel Angevain Joëlle Ronfort 《Genetic Resources and Crop Evolution》2006,53(4):843-856
One hundred and three natural populations of Medicago L. were collected in Spain, mainly from roadsides, non-irrigated or grazed lands. This germplasm was evaluated at Montpellier
(France) with control cultivars and Spanish landraces under completely random block design, replicated four times, and observed
for 64 qualitative or quantitative characters. Differences between natural populations and cultivated controls are highly
significant, but gene flow occurs between wild and cultivated compartment and hybrid populations were identified. On the basis
of multivariable analysis, the accessions were grouped into four clusters depending on their proximity with the cultivated
pool to facilitate their management and ex situ conservation. The relationship between environment of the site of collection and phenotypic characteristics of the natural
populations was also discussed. Different policies of conservation of these genetic resources are suggested to avoid their
disappearance even when they disappeared from the other regions of the western Mediterranean. Spanish wild pool of alfalfa,
also called ‘Mielga’, appears of great interest for the breeding of alfalfa because it contains a large diversity of characteristics
(prostrate habit, rhizomes) linked to tolerance to grazing or drought environment. With the need for more sustainable systems
in agriculture, the erosion of natural habitats and the necessity for rehabilitation of degraded ecosystems, the importance
of this wild pool is really inestimable. 相似文献
20.
Elena Albrecht Dapeng Zhang Robert A. Saftner John R. Stommel 《Genetic Resources and Crop Evolution》2012,59(4):517-538
Capsicum baccatum is one of five domesticated pepper species which, despite its morphological and ecological variability, has been underexploited
for germplasm improvement. Utilizing a broad spectrum of domesticated and wild C. baccatum germplasm, we utilize AFLP markers to describe the species’ molecular diversity and population structure in the South American
gene pool. Analysis of molecular variance (AMOVA) revealed greater genetic diversity in the wild form of C. baccatum (C. baccatum var. baccatum) than in the domesticated form of the species (C. baccatum var. pendulum). Both Bayesian and distance based clustering analysis, as well as principal coordinates analysis (PCA), concordantly demonstrated
admixture/shared ancestry between wild and cultivated C. baccatum botanical varieties. Two principal genetic groups were identified in the domesticated C. baccatum accessions largely based on their geographic distribution in South America. One group was predominated by accessions from
the western territories of the species’ distribution (Peru, Colombia, Ecuador, Bolivia, Chile and northwestern Argentina)
and the second by accessions from the eastern regions, Paraguay and eastern Argentina). The two genetic groups overlapped
in the geographic location of present-day Bolivia. The grouping pattern suggested that C. baccatum was domesticated in multiple sites and that its evolution took two lineages followed by lineage differentiation. The wild
accessions most closely related to the cultigens were found in the highlands of Peru and Bolivia, which support the early
hypothesis that this region is one of the domestication sites of this species. A Bayesian assignment analysis demonstrated
that Brazilian wild forms of C. baccatum were genetically distant to all other accessions and made little to no contribution to the domesticated genepool. Moreover,
results of clustering analysis suggested that C. baccatum likely originated from present day Paraguay. Analysis of inter-specific relationships across selected Capsicum species supported independent lineages for the two crossability groups within Capsicum, the baccatum species-complex (including C. baccatum) and the annuum species-complex (including C. annuum, C. chinense and C. frutescens). However, the results did not support taxonomic distinction of C. baccatum var. umbilicatum from C. baccatum var. pendulum. The present study provides new insights into the domestication of C. baccatum. The results will be useful for identifying accessions for crop improvement and guiding the development of in situ and ex situ conservation programs. 相似文献