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1.
Genetic diversity and population genetic structure of Aegilops tauschii in Northern Iran were studied based on nine microsatellite loci. A high level of genetic diversity was observed from the accessions collected from six regions (provinces). These accessions include 79 samples of the two subspecies (tauschii and strangulata), the intermediate form (among morphologically distinguished subspecies) and ten accessions of Triticum aestivum. The nine microsatellites revealed a total of 141 alleles, with an average of 15.7 alleles per locus. A comparison of the parameters showing genetic diversity, including the observed heterozygosity (Ho), gene diversity (He) and Shannon’s information index (I) of Ae. tauschii accessions from different provinces in Northern Iran, indicated that subsp. tauschii possesses the highest genetic diversity, followed by intermediate form. Genetic distance between subsp. strangulata and subsp. tauschii was low, confirming high gene flow between these two subspecies. However, intermediate form was more distinct from both of them. It was also found that the genetic diversity of T. aestivum is obviously lower than that of Ae. tauschii accessions. Moreover, the level of genetic diversity for Gilan, Golestan and Mazanderan provinces was higher than for Ardebil, Ghazvin and Semnan provinces, suggesting that these regions may provide a readily available source of potentially useful variation for wheat improvement.  相似文献   

2.
All the 79 Aegilops tauschii Coss. accessions of Iranian origin from Prof. Kihara’s collection were analyzed electrophoretically. Of 23 enzyme-encoding loci studied, 11 were polymorphic. In Iran Ae. tauschii is presented by ssp. tauschii and ssp. strangulata which distinctly differ genetically, morphologically and ecologically. Variation patterns of low polymorphic locus Aco2 and highly polymorphic Ep are similar in both subspecies. In contrast, variation of Acph1, Ak, Est2, Est5, Got1, Got2, Got3 and Lap is a set of diverse patterns which markedly differ between subspecies and natural regions also, implying that natural selection is involved.  相似文献   

3.
The diploid goatgrass Aegilops tauschii is considered the D-genome donor of bread wheat and has probably a centre of diversity in north of Iran. In order to measure the genetic diversity of and the relationships among different populations, varieties and subspecies belonging to Ae. tauschii in Iran, DNA was extracted from 48 accessions of Ae. tauschii collected across the geographic range of the species in the Country and the genetic diversity was assessed using AFLPs based on eight PstI/MseI +3 primer pairs resulted in 277 bands, 198 of which were polymorphic. High level polymorphism was detected, with an average of polymorphism rate of 0.715; relatively low genetic similarity (0.455) between accessions and significant difference between the lowest (0.179) and the highest genetic similarity (0.817). The Iranian Ae. tauschii populations showed high level of genetic diversity. The populations studied were divided into two groups: one group was mainly representing Northern populations collected from Southern Caspian Sea shore and the other group was mainly representing Northeast and Northwest populations. Based on the results of this study, it can be suggested that Ae. tauschii possesses two separate gene-pools in Iran: Northern and Northeastern–Northwestern. Considering the needs for introducing new characteristics and alleles for wheat improvement purposes, Ae. tauschii Iranian gene-pool is assumed to be of high importance for more investigation in the future.  相似文献   

4.
Variation of high molecular weight glutenin subunits (HMW-GS) in 28 Iranian Aegilops tauschii (2n = 2x = 14, DD) accessions studied by sodium dodecyl sulphate electrophoresis method (SDS-PAGE). The results showed high variation of HMW-GS in the accessions. The range of frequency in 14 HMW-GS combinations was 3.57–25 % in the accessions. AMOVA showed the molecular variance between the geographic areas was lower than within the geographic areas. According to Nei’s genetic diversity, the highest diversity levels were in Semnan, Golestan and Azarbayjan, on the other hand the lowest levels of diversity were found in Khorasan, Gilan and Mazandaran accessions. Hence, the Caspian Sea South East accessions also Azerbayjan in Iran have more diversity. AMOVA did not show variance between strangulata and tauschii but there was more genetic diversity in ssp. tauschii subspecies in comparison of ssp. strangulata according to Nei’s gene diversity and Shannon information index. It showed Iranian Ae. tauschii have a good potential for bread making quality improvement in bread wheat.  相似文献   

5.
Geographic patterns of Got1, Got2, Got3 and Est2 enzyme-encoding genes allelic variation were investigated among 322 accessions of Aegilops tauschii Coss., 161 accessions of ssp. tauschii and 161 accessions of ssp. strangulata, representing all the species area. It was found that: (1) in the two ecologically different subspecies, ssp. tauschii and ssp. strangulata, the patterns of allelic variation of the four genes differ greatly; (2) the same allozymes have originated several times independently in different Ae. tauschii local populations; (3) allelic variation of Got1, Got3 and Est2 in ssp. strangulata corresponds to climatic conditions. The data obtained reflected that Ae. tauschii has been inhabiting its area from ancient times; and allelic variation patterns of Got1, Got2, Got3, Est2 loci were mostly formed by natural selection. Further investigations of these loci with molecular genetic methods are prospective for understanding the peculiarities of Ae. tauschii evolution.  相似文献   

6.
Aegilops tauschii Coss., the D-genome progenitor of common wheat (Triticum aestivum L.) includes two subspecies, tauschii and strangulata (Eig) Tzvel. Subspecies tauschii has a wide geographic distribution spreading westwards to Turkey and eastwards to Afghanistan and China, while ssp. strangulata has a narrower distribution occurring only in two disjoined regions, southeastern Caspian Iran and Transcaucasia. A collection of 56 Ae. tauschii accessions was screened at adult stage against a mixture of pathotypes of stripe rust prevalent in the current wheat production in China. The results for three crop seasons indicated that among the 38 ssp. tauschii accessions, 37 were susceptible and only one was resistant, while all the 18 ssp. strangulata accessions were resistant. These results indicated that stripe rust resistance was related to taxonomic origin. Further genetic analysis revealed the resistance of stripe rust in ssp. strangulata accession AS2388 was conferred by a single dominant gene.  相似文献   

7.
Sequences of four chloroplast DNA non-coding regions, about 3,000?bp in total, were analysed in 112 Aegilops tauschii accessions, 56 of ssp. tauschii and 56 of ssp. strangulata, representing all of the species range. One inversion, 8 insertions/deletions, 18 base pair substitutions and 5 microsatellite loci were found. The data revealed that Ae. tauschii originated in Caucasia. Neither of the two Ae. tauschii subspecies was an ancestor to one another. Aegilops tauschii divided into ssp. tauschii and ssp. strangulata at the very beginning of its existence as a species. Subspecies tauschii was the first to start geographic expansion and relatively rapidly occupied a vast area from Caucasia—eastward up to central Tien Shan and western Himalayas. In contrast to ssp. tauschii, geographic spread of ssp. strangulata was a complicated, multi-stage and slow process. At the beginning of ssp. strangulata evolutionary history its major phylogenetic lineage for a lengthy time span had existed as a small isolated population. Several forms of ssp. strangulata, better adapted to relatively moister and cooler habitats, had originated. Each of these forms has gradually forced out ssp. tauschii from some part of its area in the west, up to central Kopet-Dag.  相似文献   

8.
A study of Aegilops tauschii subspecies constitution was undertaken. The data on allozyme and morphologic variation among 308 plants from 154 accessions were used for multivariate analysis. ACPH1 and (glume width)/(rachis segment width) ratio were found to be reliable criteria to distinguish between sspp. tauschii and strangulata.  相似文献   

9.
The Ppd-D1 controlling photoperiod response is an important gene for wheat adaptation since it affects heading time. In the present study, three haplotypes, i.e. haplotype I without deletion, haplotype II with a 24?bp deletion, and haplotype III with two deletions of 24 and 15?bp, were identified in the upstream of the coding region in 80 Ae. tauschii accessions. The haplotype distribution was related to subspecies taxon. All typical ssp. tauschii accessions had haplotype I, whereas all ssp. strangulata had haplotype III. The three haplotypes were observed in Ae. tauschii with morphologically intermediate forms between the two typical subspecies. Present results supported that ssp. strangulata or intermediate form was the D-genome donor of common wheat since only haplotype III were found in wheat. Moreover, a 16?bp deletion in exon 8 of gene Ppd-D1 exists in common wheat. However, none of Ae. tauschii accessions analyzed had the 16?bp deletion.  相似文献   

10.
Investigation of spatial patterns of adenylate kinase, catalase, endopeptidase and fructose-1,6-diphosphatase encoding genes (Ak, Cat1, Cat2, Ep, Fdp) allelic variation in Aegilops tauschii was carried out. About 300 accessions, representing all the species range were taken for the study. Cat2 and Fdp loci are completely monomorphic in ssp. strangulata and in the western part of ssp. tauschii range, as well. Both Cat2 and Fdp are highly polymorphic in the eastern part of ssp. tauschii range, with the patterns of this polymorphism being discordant in these two loci. Ak 108, a rare allele with sporadical spatial occurrence, was found in ssp. tauschii only. On the contrary, Ak 92 is absent in ssp. tauschii: it is the most common Ak allele in ssp. strangulata in Precaspian Iran, the most moist part of the area, and is very rare in other parts of ssp. strangulata area. Ep is a highly polymorphic locus with the highest level of variation in the west of Ae. tauschii area, where this species had originated. Ep allele variation patterns are rather similar in ssp. tauschii and ssp. strangulata. The data reveal the adaptive nature of Ak, Cat2, and Fdp allele variation, while Ep polymorphism seems to be mostly neutral.  相似文献   

11.
Summary A collection of 400 Ae. tauschii (syn. Ae. squarrosa) Coss. accessions were screened for powdery mildew resistance based on the response patterns of 13 wheat cultivars/lines possessing major resistance genes to nine differential mildew isolates. 106 accessions showed complete resistance to all isolates, and 174 accessions revealed isolate-specific resistance, among which were 40 accessions exhibiting an identical response pattern as wheat cultivar Ulka/*8Cc which is known to possess resistance gene Pm2. Expression of both complete and isolate-specific resistance from Ae. tauschii was observed in some synthetic hexaploid wheats derived from four mildew susceptible T. durum Desf. parents, each crossed with five to 38 resistant diploid Ae. tauschii accessions. Synthetic amphiploids involving different combinations of T. durum and Ae. tauschii generally showed a decrease in resistance compared with that expressed by the Ae. tauschii parental lines.  相似文献   

12.
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   

13.
Simple sequence repeats (SSRs), highly dispersed nucleotide sequences in genomes, were used for germplasm analysis and estimation of the genetic relationship of the D-genome among 52 accessions of T. aestivum (AABBDD), Ae. tauschii (DtDt), Ae. cylindrica (CCDcDc) and Ae. crassa (MMDcr1Dcr1), collected from 13 different sites in Iran. A set of 21 microsatellite primers, from various locations on the seven D-genome chromosomes, revealed a high level of polymorphism. A total of 273 alleles were detected across all four species and the number of alleles per each microsatellite marker varied from 3 to 27. The highest genetic diversity occurred in Ae. tauschii followed by Ae. crassa, and the genetic distance was the smallest between Ae. tauschii and Ae. cylindrica. Data obtained in this study supports the view that genetic variability in the D-genome of hexaploid wheat is less than in Ae. tauschii. The highest number of unique alleles was observed within Ae. crassa accessions, indicating this species as a great potential source of novel genes for bread wheat improvement. Knowledge of genetic diversity in Aegilops species provides different levels of information which is important in the management of germplasm resources.  相似文献   

14.
Polymorphism of gliadins was investigated in Aegilops tauschii from primary habitats “4”, near Hily, and “6”, near Rukel, in Dagestan, Russia 205 individual plants were analysed (53/50 and 54/48 plants of subsp. tauschii/subsp. strangulata from the habitats “4” and “6”, respectively) and 1/7 and 18/14 different haplotypes were found among the plants of subsp. tauschii/subsp. strangulata from the habitats “4” and “6”, respectively. No direct evidences of cross-pollination were pointed out, although gliadins electrophoretic phenotypes obtained allowed to suggest that it occur in Ae. tauschii with very low frequency. The data obtained revealed that during Ae. tauschii evolutionary history a local habitat could be populated many times by different phylogenetic lineages of the species. It was found that in Dagestan, at the very edge of the species area, several different lineages belonging to different subspecies could for a long time co-exist together in a local habit, and in such case a very high level of genetic variation in Ae. tauschii could be accumulated on a square of less than one hectare. The further studies of genetic variation in Ae. tauschii local populations, based on molecular genetic methods seems to be very prospective for understanding of peculiarities of the species evolution.  相似文献   

15.
A collection of 164 Aegilops tauschii accessions, obtained from Gatersleben, Germany, was screened for reaction to leaf rust under controlled greenhouse conditions. We have also evaluated a selection of synthetic hexaploid wheats, produced by hybridizing Ae. tauschii with tetraploid durum wheats, as well as the first and second generation of hybrids between some of these resistant synthetic hexaploid wheats and susceptible Triticum aestivum cultivars. Eighteen (11%) accessions of Ae. tauschii were resistant to leaf rust among which 1 was immune, 13 were highly resistant and 4 were moderately resistant. Six of the synthetic hexaploid wheats expressed a high level of leaf rust resistance while four exhibited either a reduced or complete susceptibility compared to their corresponding diploid parent. This suppression of resistance at the hexaploid level suggests the presence of suppressor genes in the A and/or B genomes of the T. turgidum parent. Inheritance of leaf rust resistance from the intercrosses with susceptible bread wheats revealed that resistance was dominant over susceptibility. Leaf rust resistance from the three synthetics (syn 101, syn 701 and syn 901) was effectively transmitted as a single dominant gene and one synthetic (syn 301) possessed two different dominant genes for resistance.  相似文献   

16.
Three hundred and seven accessions of Aegilops tauschii Coss., including 160 of subsp. tauschii and 147 of subsp. strangulata, representing all the species range—from Turkey to Kirgizstan, were analyzed electrophoretically. Twenty polymorphic enzyme-encoding loci were studied, 10 of which were essentially polymorphic in Ae. tauschii. Climatic data for each of the 307 Ae. tauschii habitats were taken from WORLDCLIM database of computer system ArcGIS. Forty-nine climatic parameters were considered: precipitation, minimum, mean and maximum temperatures for each month, and also the total annual level of precipitation. The data were analyzed with multivariate statistical methods, such as Principal Components Analysis (PCA), Multiple Correspondence Analysis (MCA) and Two-Block Partial Least Squares. Variability of climatic conditions among Ae. tauschii habitats is reflected by the two approximately orthogonal “vectors”. The “first vector” is mostly determined by negative impact of precipitation and minimum temperatures during winter. The “second vector” is mostly determined by negative impact of maximum temperatures during summer, and positive impact of precipitation during late spring and summer. Aegilops tauschii is essentially variable along the “second vector”, and especially high level of variation is characteristic for subsp. tauschii. This variation reflects that Ae. tauschii is very tolerable to the climatic variation during summer season. Aegilops tauschii subsp. strangulata is also characterized by the high level of variation along the “first vector”. Moreover, all the habitats of subsp. strangulata fall into the two distinct separate clusters: the habitats in Precaspian Iran, which have the highest minimum temperatures in winter,—and all the other habitats. In the plot of the first two factors of PCA, the “cluster of Precaspian Iran” can be further divided into “Western Precaspian Iran (WPI)”, having relatively higher level of annual rainfall, and relatively dryer “Eastern Precaspian Iran (EPI)”. This three groups of subsp. strangulata accessions, from WPI, EPI and other areas, are also distinctly differed in enzyme-encoding genes allelic variation, as revealed on the plot of the first two axes of MCA. In contrast to subsp. strangulata, the level of variation of subsp. tauschii along the “first vector” is rather low. It was pointed out that variation along “the first vector” reflects adaptive intraspecies divergence of Ae. tauschii: its subspecies strangulata “prefers” the habitats of seaside climate, with warm and moist winter; while subsp. tauschii mostly occupies the habitats with rather continental climate, with relatively cold and dry winter. Allelic variation of enzyme-encoding genes Acph1, Ak, Est2, Est5, Got1, Got2, and Got3 correlate with climate along “the first vector”. Apparently, polymorphism of these loci were involved into the process of Ae. tauschii intraspecies adaptive divergence. Allelic variation of Cat2 and Fdp loci correspond to climatic variation along “the second vector” in subsp. tauschii. Therefore Cat2 and Fdp are likely to be among the genes which polymorphism “helped” subsp. tauschii to succeed in vast geographical expansion far to the east from Caspian Sea.  相似文献   

17.
Two hexaploid species of Solanum sect. Solanum are present in Africa: Solanum scabrum and S. nigrum. Solanum scabrum is a widely cultivated species and is used as a leafy vegetable, as a source of medicine and as a source of ink dye. In previous studies a wide range of morphological diversity has been reported in this species and in some studies subspecies have been proposed. Subspecies are also recognized in S. nigrum. However, it has not been established whether or not the morphological differences are reflected at the genomic level. The present study applies AFLPs to study the genetic diversity in S. scabrum and its relationship to geographical provenance, morphological differences and the possible existence of subspecies within S. scabrum and S. nigrum. The data obtained were analyzed with cluster analysis (using UPGMA and NJ). The results indicate that the genetic variation within S. scabrum was higher within accessions than between accessions. Accessions did not cluster according to their geographical provenance, indicating that accessions from different geographical areas were not significantly different genetically. The clustering reflected neither morphological differences nor domestication status (cultivated or wild). The morphological differences exhibited by S. scabrum could be due to selection by farmers for different plant types. The AFLP derived clustering pattern did not segregate the subspecies recognized in S. scabrum and S. nigrum into separate subclusters.  相似文献   

18.
Hexaploid bread wheat (Triticum aestivum L. ssp. aestivum) is assumed to have originated by natural hybridization between cultivated tetraploid Triticum turgidum L. and wild diploid Aegilops tauschii Coss. This scenario is broadly accepted, but very little is known about the ecological aspects of bread wheat evolution. In this study, we examined whether T. turgidum cultivation still is associated with weedy Ae. tauschii in today’s Middle Eastern agroecosystems. We surveyed current distributions of T. turgidum and Ae. tauschii in northern Iran and searched for sites where these two species coexist. Ae. tauschii occurred widely in the study area, whereas cultivated T. turgidum had a narrow distribution range. Traditional durum wheat (T. turgidum ssp. durum (Desf.) Husn.) cultivation associated with weedy Ae. tauschii was observed in the Alamut and Deylaman-Barrehsar districts of the central Alborz Mountain region. The results of our field survey showed that the T. turgidum–Ae. tauschii association hypothesized in the theory of bread wheat evolution still exists in the area where bread wheat probably evolved.  相似文献   

19.
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20.
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   

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