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1.
Triticum tauschii (Coss.) Schmalh. (Aegilops squarrosa auct. non L., 2n=2x=14, DD genome) with its diverse range of accessions and distribution provides a unique opportunity for exploiting novel genetic variability for wheat (T. aestivum L.) improvement associated with biotic/abiotic stress factors. From our working collection of 490 T. tauschii accessions we have so far produced 430 different synthetic hexaploids (2n=6x=42, AABBDD) resulting from the chromosome doubling of Triticum turgidum L. s. lat. x T. tauschii F1 hybrids (each synthetic involving a different T. tauschii accession). We present here our results on hybrid production, plantlet regeneration, cytology, colchicine induced doubling of the 2n=3x=21 chromosome F1 hybrids, seed increase of the doubled progeny and screening for a biotic stress; Cochliobolus sativus Ito and Kuribay (syn. Helminthosporium sativum Pamm. King and Bakke); of 250 of these synthetic hexaploid (2n=6x=42) amphiploids. Application of the direct crossing methodology involving susceptible T. aestivum cultivars with resistant T. tauschii accessions is also alluded to. 相似文献
2.
Diego Hojsgaard Ana I. Honfi Gabriel Rua Julio Daviña 《Genetic Resources and Crop Evolution》2009,56(4):533-545
Somatic chromosome numbers of 131 accessions belonging to 55 Paspalum species from subtropical South America have been determined. All species had x = 10 as a basic chromosome number, except P. almum which had x = 6. Six ploidy levels were found among species with tetraploidy as the most frequent condition. New diploid and octoploid
counts were reported. For Paspalum lilloi and P. glabrinode (both 2n = 2x = 20), and for P. ellipticum, P. erianthoides, P. ovale and P. remotum (all 2n = 8x = 80) sporophytic chromosome numbers are presented for the first time. Records that differ from previously reported counts
are given for the following species: P. paucifolium (2n = 2x = 20), P. ceresia (2n = 6x = 60), P. conjugatum (2n = 6x = 60), P. alcalinum (2n = 6x = 60) and P. aff. arundinellum (2n + 1 = 5x + 1 = 51). These chromosome data are discussed in light of ploidy-level variation and implications for breeding systems within
and among species. 相似文献
3.
The collection, identification and maintenance of genebank accessions of the genus Trifolium is a major task because of the large number of genera and their occasional morphological similarity. We investigated whether
the measurement of nuclear DNA content can serve as an additional criterion for identification of mislabeled accessions. Relative
nuclear DNA content was determined by flow cytometry measurements for a total of 151 genebank accessions of 23 Trifolium species with notable agronomical value. Among 23 species analyzed, 15 were found to possess a uniform relative nuclear DNA
content, with intraspecific variability of the majority of analyzed species lower than 5%. Within six Trifolium species, 1–2 atypical accessions with outstanding differences in relative DNA content, chromosome number and morphological
features were found. In T. hybridum and partially in T. ambiguum these outstanding differences could be ascribed to variations in accession ploidy level. For the remaining atypical accessions,
the determined nuclear DNA content, chromosome number and morphological features were not related to those characteristic
of the species. Additionally taxonomic identity of atypical accessions was determined using ITS region sequencing and morphological
observations. We propose flow cytometric measurements of nuclear DNA content as simple and reliable technique which can be
used at seedling stage to verify identity and genetic stability of Trifolium genebank accessions. 相似文献
4.
The genus Arachis is divided into nine taxonomic sections. Section Arachis is composed of annual and perennial species, while section Heteranthae has only annual species. The objective of this study was to investigate the genetic relationships among 15 Brazilian annual
accessions from Arachis and Heteranthae using RAPD markers. Twenty-seven primers were tested, of which nine produced unique fingerprintings for all the accessions
studied. A total of 88 polymorphic fragments were scored and the number of fragments per primer varied from 6 to 17 with a
mean of 9.8. Two specific markers were identified for species with 2n = 18 chromosomes. The phenogram derived from the RAPD data corroborated the morphological classification. The bootstrap analysis
divided the genotypes into two significant clusters. The first cluster contained all the section Arachis species, and the accessions within it were grouped based upon the presence or absence of the ‘A’ pair and the number of chromosomes.
The second cluster grouped all accessions belonging to section Heteranthae. 相似文献
5.
The chromosome morphology and the variation in the N-band distribution along the chromosomes were studied in 13 accessions of the wild wheat Aegilops geniculata Roth (2n=28, genome formula UUM°M°). The karyotype consisted of four metacentric, five submetacentric, three subtelocentric, and two satellited pairs of chromosomes. The N-banding technique stained differentially all 14 chromosome pairs. The most prominent bands were observed near the centromeres and in the intercalary regions of both arms. Telomeric bands were found in only seven chromosomes. All chromosomes produced a specific banding pattern, permitting their identification. Polymorphism for presence or absence of particular bands was observed among the different accessions. The variable bands were located predominantly at the terminal and subterminal chromosome regions, and were also unevenly distributed over chromosomes. This polymorphism resulted in up to eight distinct banding pattern variants for each of the Ae. geniculata chromosomes. Each accession in this study showed a unique overall karyotype, sharing 0 to 8 chromosomes of identical banding pattern with the other accessions. A generalized idiogram of Aegilops geniculata is presented. 相似文献
6.
Andreas Börner Ulrich Freytag Ursel Sperling 《Genetic Resources and Crop Evolution》2006,53(3):453-465
Series of 10,348 accessions belonging to 21 species (hexaploid, tetraploid, diploid) of the genus Triticum and 489 accessions belonging to 20 species of the genus Aegilops were scored for disease resistance during a period of 60 years. Tests were performed at the seedling stage for powdery mildew
(Erysiphe graminis DC. f. sp. tritici March.), leaf rust (Puccinia recondita Rob. ex Desm. f. sp. tritici Erikss.), stripe rust (Puccinia striiformis West. f. sp. tritici Erikss.) and eyespot (Pseudocercosporella herpotrichoides (Fron.) Deight.) but also at the adult plant stage considering powdery mildew, leaf rust, stripe rust, eyespot and glume
blotch (Septoria nodorum Berk.). About 150,000 disease scores recorded on index cards using different scoring scales were transferred to the computer,
converted into a 1–9 scale and used to summarise the results. Within the genus Triticum 20% of the material analysed was classified as heterogeneous. For the accessions without detectable segregation a large variability
for resistance/susceptibility was detected. At the adult plant stage resistant accessions without visible infections were
identified for all diseases. The percentages of resistant accessions at that growth stage were always higher than the ones
found in the material tested at the seedling stage. The probability for finding resistant material was shown to be highest
in the diploid species ( > 50%) but decreased with increasing ploidy level to about 10% in the hexaploids. For Aegilops it was shown that most of the accessions were homogeneous and highly resistant against powdery mildew (seedling and adult
plant stage), leaf rust (adult plant stage) and eyespot (seedling and adult plant stage/natural infection). The data obtained
for the individual accessions are available via Internet (http://www.ipk-gatersleben.de).
An erratum to this article is available at . 相似文献
7.
Paula Macedo Nóbile Marcos Apareado Gimenes José Francisco Montenegro Valls Catalina Romero Lopes 《Genetic Resources and Crop Evolution》2004,51(3):299-307
The genus Arachis is endemic to South America and comprises 80 species, 69 of which have already been described and eleven not yet published. The genus includes the cultivated peanut (A. hypogaea) and several forage species, the most important ones being A. glabrata and A. pintoi. Accessions of section Rhizomatosae, including three tetraploid species 2n = 4x = 40 (A. glabrata, A. pseudovillosa and A. nitida nom. nud.) and one diploid species 2n = 2x = 20 (A. burkartii), were evaluated using RAPD markers to assay genetic variability within and among species. The ten random primers used yielded a total of 113 polymorphic bands. The data were scored as the presence or absence of each band in each sample. A distance matrix and dendrogram were obtained using Link's coefficient and the neighbor-joining method. Most accessions analyzed grouped into two major clusters: the first comprised most accessions of A. glabrata and accessions of A. nitida, and the second cluster comprised accessions of A. burkartii. Arachis pseudovillosa and a few accessions of A. glabrata and A. nitida were placed between these major clusters. The diploid and tetraploid species were grouped quite separately, suggesting that the tetraploids did not originate from the diploid species analyzed. 相似文献
8.
V. Sérgio Emílio Dos Santos M. Aparecido Gimenes J. Francisco Montenegro Valls C. Romero Lopes 《Genetic Resources and Crop Evolution》2003,50(8):841-848
Some Arachis species are widely used as commercial plants, e.g. the groundnut A. hypogaea, an important source of good quality protein and oil, and A. pintoi and A. glabrata, that are utilized as forage species. Germplasm of most Arachis species is available in germplasm banks. However, little it is known about the genetic attributes of this germplasm, and mainly about its genetic variability, which is very important for its maintenance. In the present study RAPDs were used to assay the genetic variation within and among 48 accessions of five sections of the genus Arachis and to establish the genetic relationships among these accessions. Ten of 34 primers tested were selected for DNA amplification reactions since they yielded the largest numbers of polymorphic loci. A dendrogram was constructed based on data from the 10 primers selected. Eighty RAPD polymorphic bands were analyzed among the accessions studied. The relationships among species based on RAPDs were similar to those previously reported based on morphological, cytological and crossability data; demonstrating that RAPDs can be used to determine the genetic relationships among species of the different sections of the genus Arachis. In general, wide variation was found among accessions and low variation was found within the accessions that had two or more plants analyzed. However, higher polymorphism was found in the section Trierectoides and in one accession of A. major, indicating that generalizations should be avoided and each species should be analyzed in order to establish collection and maintenance strategies. 相似文献
9.
Xiaoping Ren Jiaquan Huang Boshou Liao Xiaojie Zhang Huifang Jiang 《Genetic Resources and Crop Evolution》2010,57(6):903-913
The Arachis genus is native to South America, and contains 70–80 described species assembled into nine sections. A better understanding
of the level of speciation and taxonomic relationships is a prerequisite to the effective use of Arachis species in peanut breeding programs. Forty-eight genotypes representing 19 species in 6 sections were evaluated to assay
the genetic variability within and among species, and 10 recombinant lines and those parents were identified with introgression
of Arachis species chromosome segments into A.
hypogaea genome using SRAP markers. Sixty of sixty-four SRAP primers tested were selected for DNA amplification reactions. A dendrogram
and principal component analysis were constructed based on 353 SRAP polymorphic bands of the accessions. The number of scored
polymorphic bands per each primer combination varied from 1 to 25 with an average of 5.9 per reaction. Estimates of genetic
distance among the 48 accessions Arachis species ranged from 0.11 to 0.76. A-genome accessions 475845 (A. duranensis), and 331197 (A. villosa) were most closely associated to A.
hypogaea. The first two PCAs accounted for 77.74% (62.02 and 15.72%) of the total variation observed and separated the different genomic
groups. SRAPs also identified introgression of Arachis species chromosome segments into A.
hypogaea. genome with 10 recombinant lines and those parents. The present results indicated that SRAPs can be used to determine the
genetic relationships among species of the different sections of the genus Arachis and to identify introgression of Arachis genus chromosome segments into A.
hypogaea genome. 相似文献
10.
As a part of the characterization and the valorization of plant genetic resources of fodder and pastoral interest in Algeria,
a cytogenetic study was undertaken for nine natural populations of Hedysarum coronarium L. originating from North-East Algeria. The chromosomic characterization was realized throughout the mitosis, the C-banding
and the meiosis analysis. Ecological factors (altitude and rainfall) of the originating environment of the different populations
were considered in this study. Six Algerian populations present the stable chromosome number, usually observed in this species
(2n = 16), whereas three others present two numbers. The first number (2n = 2x = 16), previously cited by other authors throughout the world, and the second one (2n = 2x = 18) is newly observed within Hedysarum coronarium L. Both mitotis ans meiosis confirmed these numbers. The chromosomes are median and the karyotype is primitive in terms of
form and size. The C-banding method showed off three types of bands (telomeric, intercalary, centromeric). The originating
environment seems to have an effect on the existing variability in Hedysarum coronarium L. 相似文献
11.
Hojjatollah Saeidi Mohammad Reza Rahiminejad Sadeq Vallian J. S. Heslop-Harrison 《Genetic Resources and Crop Evolution》2006,53(7):1477-1484
Microsatellite markers were used to analyse the biodiversity of 57 accessions of different subspecies and varieties of wild
Aegilops tauschii (2n = 2x = 14; D genome) collected across the major areas where it grows in Iran. Levels of diversity were high, with numbers of alleles
averaging 7.3 (ranging up to 12) and polymorphism information contents averaging 0.6591. One accession was notably more similar
to two of the D genome in hexaploid wheats (Triticum aestivum) used as outgroups. Within the Ae. tauschii accessions, no markers were characteristic for taxa or geographical origin, suggesting high gene flow between the subspecies
and varieties, although some groupings, which could be related to geographical origin, were evident. This survey demonstrates
the high diversity present in wild goatgrass in Iran, and indicates that there is value in sampling for useful genes for wheat
breeding. 相似文献
12.
N. P. Goncharov S. V. Bannikova T. Kawahara 《Genetic Resources and Crop Evolution》2007,54(7):1507-1516
The effective utilisation of available genetic resources of related species is essential for successful crops breeding and
maintaining genetic variability within crops. Bread wheat, the basic cultivated wheat species, is an amphiploid (2n = 6x = 42) and, therefore, the production of new synthetic amphiploids using genomes of related species should reduce the difficulties
caused by direct crossings, for example, between hexaploid wheat and diploid relatives. Hence, exploiting synthetic amphiploids
is an effective and rapid way of introgressing desirable traits from related species into cultivated wheats. Some of the artificial
amphiploids that already exist were produced 80 years ago. Yet little work has been done to highlight potential contamination
and/or genetic changes during their conservation by genebanks. Thus, we utilised the electrophoresis of wheat endosperm storage
proteins (gliadins) to check such amphiploid authenticity, and also where differences had been previously observed between
synthetic wheat amphiploids. In addition, we checked putative amphiploid accessions where Triticum timopheevii (GGAtAt) was recorded as one of the parents. A synthetic species, T. timococcum produced by Kostov, together with a natural T. zhukovskyi found in Georgia (the former Soviet Union) were revealed to be identical according to our assays. The existence of several
T. kiharae accessions independently produced by different authors was confirmed, and they exhibited polymorphism for a number of traits,
including spike characters (awning, hairy glumes) and growth habit (spring vs. winter). The effective conservation of artificial
amphiploids in genebanks is discussed. 相似文献
13.
Apekshita Singh R. M. Devarumath S. RamaRao V. P. Singh S. N. Raina 《Genetic Resources and Crop Evolution》2008,55(1):65-79
Repeat unit length variation and internal transcribed spacer (ITS) sequences of nuclear ribosomal DNA were used to assess
genetic diversity, and phylogenetic relationships in chickpea (C. arietinum) cultivars, and its related wild species. Total genomic DNAs of 76 accessions of 10 Cicer species, belonging to three sections of the genus, were restricted with seven enzymes and the restriction fragments were
hybridized to heterologous ribosomal clones of wheat pTa71 and Vicia faba probes Ver 6-5 and Ver18-6. A single repeat unit length class of 11.4 kb or 10.5 kb was recognized across Cicer accessions with pTa71. The intraspecific variation was negligible in those species where more than one accession was studied,
except the four C. judaicum accessions, which were different from the rest. EcoRI and DraI digests gave two and one-two fragments, respectively. All the accessions produced three and three-five bands with BamHI and SacI, respectively. Both the accessions of C. yamashitae differed in their rDNA repeat unit length as well as restriction site variation. Maximum likelihood tree with rDNA RFLP recognized
five clades which were more or less congruent with the previous data. Length of ITS-1 region was more variable (235–239 bp)
than the ITS-2 region (212–213 bp). Cladistic analysis of ITS data revealed two major clades, clade I consisting of C. arietinum, C. reticulatum and C. echinospermum, and clade II comprised of C. judaicum, C. chorassanicum, C. bijugum and C. cuneatum. C. microphyllum grouped with the above four species. C. pinnatifidum was present as a separate branch. C. yamashitae emerged as the most distinct species. 相似文献
14.
M. C. Vaz Patto M. Fernández-Aparicio A. Moral D. Rubiales 《Genetic Resources and Crop Evolution》2007,54(7):1517-1521
Several Lathyrus species have a considerable potential as alternative pulses in sustainable dryland farming systems mainly due to their high
tolerance to drought and disease resistance. Powdery mildew is a serious disease affecting several Lathyrus species. Little is known on the availability of resistance and the underlying resistance mechanisms against powdery mildew
in the Lathyrus genus. The present study assessed and characterized the resistance reaction to powdery mildew, Erysiphe pisi, in a collection of Iberian Lathyrus cicera accessions. In general, a compatible reaction with no macroscopically visible necrosis was observed but accessions with reduced
disease severity despite of a high infection type have also been identified. This Partial Resistance was in some accessions
only expressed in the adult plant stage. The controlling genes of the Lathyrus resistance mechanisms can be of great interest not only for the Lathyrus improvement per se but also for related legume species, like field pea. 相似文献
15.
Oryza officinalis complex is the largest and the most complicated group in the genus Oryza L., consisting of about ten species with the B, C, BC, CD, and E genomes. Taxonomy and identification of the species, particularly those with the B, C and BC genomes, are difficult due to the similar morphology and overlapping distribution of some species. The difference in ploidy levels of some species adds more complexity. In the present study, we surveyed 64 accessions of rice germplasm in the O. officinalis complex using RFLP analysis of PCR-amplified Adh genes in addition to chromosome counting. The results confirmed that all O. rhizomatis accessions are diploids with the C genome, whereas all O. minuta accessions are tetraploids having the BC genome. However, both diploid and tetraploid forms were found for the accessions identified in the genebank as O. officinalis, O. punctata and O. eichingeri. The tetraploid form of O. officinalis with the BC genome is exclusively distributed in India and has been described as O. malampuzhaensis. The tetraploid form of O. punctata which has been called O. schweinfurthiana by some workers was found to be as widely distributed as its diploid form in Africa. It is noteworthy that two accessions that had been determined as tetraploid O. officinalis were actually belonging to a species with the CD genome (O. latifolia). Our results promote a better understanding of the genomic constitutions of many accessions in the O. officinalis complex and correct determination of the genebank material, which serves as an important basis of germplasm cataloguing for further research and utilization. 相似文献
16.
Determination of Ploidy Level and Nuclear DNA Content in Tunisian Populations of Atriplex halimus L.
Kheiria Hcini David J. Walker Sadok Bouzid Elena González Nora Frayssinet Enrique Correal 《Genetic Resources and Crop Evolution》2006,53(1):1-5
Atriplex halimus L. (Chenopodiaceae) (Saltbush) is a perennial species used as a fodder shrub for livestock in arid and semi-arid areas, particularly
in North Africa. The aim of this work was to determine whether differences in ploidy level and/or nuclear DNA content exist
among populations from widely-separated sites in Tunisia. We determined nuclear DNA content and chromosome numbers for populations
of A. halimus from seven different locations (Gabes, Medenine, Tataouine, Monastir, Tunis, Sidi Bouzid, Kairouan). The chromosome counts
showed that all the Tunisian populations, plus a population from Eraclea (Italy), were tetraploid (2n = 4x = 36) whereas a population from Cala Tarida (Spain) was diploid (2n = 2x = 18). With respect to nuclear DNA, the 2C DNA content of population Cala Tarida was estimated to be 2.41 pg. There was no
significant difference among the tetraploid populations (or among plants within populations), whose 2C DNA content ranged
from 4.92 to 4.97 pg. 相似文献
17.
M. Costea D. M. Brenner F. J. Tardif Y. F. Tan M. Sun 《Genetic Resources and Crop Evolution》2006,53(8):1625-1633
The ‘Morelos’ accessions of Amaranthus from Mexico demonstrate taxonomic ambiguity at the basic morphologic level. The main cause is the enormous morphological
and genetic variation exhibited by the species in the genus. Although basic morphological criteria can be applied to herbarium
specimens or germplasm collections for quick taxonomic identification, the morphological data alone can be misleading. To
ascertain the taxonomic identity of the ‘Morelos’ accessions and their hypothesized species affiliation to Amaranthus caudatus or Amaranthus cruentus, we conducted a comparative analysis of phylogenetic relationships among these taxa/accessions using amplified fragment length
polymorphism (AFLP) and micromorphology methods. Based on AFLP data, all the controversial ‘Morelos’ accessions can be consistently
placed into a single A. cruentus species clade, which is clearly separated from the A. caudatus species clade. The AFLP-based phylogenetic relationship of ‘Morelos’ and delimitation of A. cruentus and A. caudatus are further supported by micromorphology, showing that the combination of these techniques can provide more reliable data
for germplasm identification than each method used alone. 相似文献
18.
Yun-Feng Zhang Chun-Yong Zhang Ting Zhang Hui-Ling Guang 《Genetic Resources and Crop Evolution》2011,58(3):461-470
Radix Campanumoeae (C. javanica Bl.) has been used in Miao herbal medicine to treat neurasthenia and consumptive disease for hundreds of years. Though Radix
Campanumoeae shows great potential for utilization in medical studies, this herb crop has not been cultivated industrially
in China. Many species in the Campanumoea genus are similar in phenotype; therefore, a karyotypic study would prove useful for clearly distinguishing Radix Campanumoeae
from related species within the same genus, for germplasm preservation and for breeding Radix Campanumoeae. 10 accessions
of four species in this genus and 5 accessions in 5 relative genera from SCSB were used for karyotype determination. The results
showed a karyotype of 2n = 16 = 2m + 12sm + 1st in Campanumoea, and a karyotype of 2n = 18 = 6 m + 12sm in Cyclocodon. Based on the chromosome number and the karyotypic formula, we suggest that the Campanumoea genus can be divided into two genera, which is in agreement with results observed from pollen morphology and from homological
usage in Chinese herbal medicine. The chromosome length in C. javanica subsp. javanica and C. javanica subsp. japonica Makino, ranged from 2.24 to 1.38 μm and 2.04 to 1.31 μm, respectively; and their haploid sets were almost identical (13.15
and 13.16 μm, respectively). This indicates that chromosomal rearrangements occur within chromosomes IV, V and VII without
a net gain or loss of genetic material. 相似文献
19.
P.R. Ellis N.B. Kift D.A.C. Pink P.L. Jukes J. Lynn G.M. Tatchell 《Genetic Resources and Crop Evolution》2000,47(4):395-401
Seven Brassica species were evaluated for their resistance to the cabbage aphid, Brevicoryne brassicae, in a series of field experiments. Four wild Brassica species, two 8 chromosome species with similarities to the B genome of Brassica nigra (Brassica fruticulosa and Brassica spinescens) and two 9 chromosome species containing the C genome (Brassica incana and Brassica villosa) were identified as possessing consistently high levels of antibiosis mediated resistance to B. brassicae. None of the species were shown to possess consistently high levels of antixenosis resistance. In more detailed glasshouse experiments one B-like genome species, B. fruticulosa, showed considerable variation between accessions collected from different sites for resistance to B. brassicae. In addition, individual accessions of one A genome species (Brassica rapa) and one C genome species (Brassica alboglabra) were shown to be highly variable in their resistance to B. brassicae, some plants of each accession being highly resistant and others very susceptible. The implications of the variability in resistance to B. brassicae within wild Brassica species for exploitation in Brassica breeding programmes are discussed. 相似文献
20.
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. 相似文献