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Background Poa L. is a large genus of grass in Gramineae, among which P. pratensis is widely cultivated as turf and forage. Satellite DNA is the main components of the plant genome. Information of satellites will helpful for dissection the genome composition and definition of the phylogeny relationship of these species. However, the knowledge about the satellites in genus Poa is still limited. Results Four satellite DNAs were identified using the Repeat Explorer pipeline in HiSeq Illumina reads from diploid plants in P. malaca (2n = 26). Two satellites showed high similarity with the previously identified PpTr-1 and PpTr-3, whereas two others are newly identified with the monomer of 326 bp (Poa-326) and 353 bp (Poa-353) respectively. The clone DNAs of PpTr-1 and PpTr-3, and oligonucleotides designed representing satellites Poa-326 and Poa-353 were probed to test on chromosomes across 13 Poa speceis with different polyploidy level by fluorescent in situ hybridization (FISH). PpTr-1, PpTr-3, and Poa-362 were stably positioned in the subtelomeric regions in nearly all species with the variation of hybridization sites number. However, Poa-353 showed different FISH patterns of multiple regions with the variation of hybridization intensity and distribution sites across species. In addition, 5S rDNA and 45S rDNA were used to characterize the genome of the Poa species. Four rDNA FISH patterns were revealed in the tested species. Conclusion Four identified satellite were high conservable across Poa species. Genome distribution of these satellites can be characterized by FISH. The variation of satellite DNAs and rDNA chromosomal distributions between species provide useful information for phylogenetic analysis in genus Poa.

The molecular karyotype could represent the basic genetic make-up in a cell nucleus of an organism or species. A doubled haploid (DH) is a genotype formed from the chromosome doubling of haploid cells. In the present study, molecular karyotype analysis of the poplar hybrid Populus simonii × P. nigra (P. xiaohei) and the derived doubled haploids was carried out with labeled telomeres, rDNA, and two newly repetitive sequences as probes by fluorescence in situ hybridization (FISH). The tandem repeats, pPC349_XHY and pPD284_XHY, with high-sequence homology were used, and the results showed that they presented the colocalized distribution signal in chromosomes. For P. xiaohei, pPD284_XHY produced hybridizations in chromosomes 1, 5, 8, and 9 in the hybrid. The combination of pPD284_XHY, 45S rDNA, and 5S rDNA distinctly distinguished six pairs of chromosomes, and the three pairs of chromosomes showed a significant difference in the hybridization between homologous chromosomes. The repeat probes used produced similar FISH hybridizations in the DH, nevertheless, pPD284_XHY generated an additional hybridization site in the telomere region of chromosome 14. Moreover, two pairs of chromosomes showed differential hybridization distributions between homologous chromosomes. Comparisons of the distinguished chromosomes between hybrid and DH poplar showed that three pairs of chromosomes in the DH presented hybridization patterns that varied from those of the hybrid. The No. 8 chromosome in DH and one of the homologous chromosomes in P. xiaohei shared highly similar FISH patterns, which suggested the possibility of intact or mostly partial transfer of the chromosome between the hybrid and DH. Our study will contribute to understanding the genetic mechanism of chromosomal variation in P. xiaohei and derived DH plants.

Kengyiliahirsuta (Keng, 1959) J. L. Yang, C. Yen et B. R. Baum, 1992, a perennial hexaploidy species, is a wild relative species to wheat with great potential for wheat improvement and domestication. The genome structure and cross-species homoeology of K.hirsuta chromosomes with wheat were assayed using 14 single-gene probes covering all seven homoeologous groups, and four repetitive sequence probes 45S rDNA, 5S rDNA, pAs1, and (AAG)10 by FISH. Each chromosome of K.hirsuta was well characterized by homoeological determination and repeats distribution patterns. The synteny of chromosomes was strongly conserved in the St genome, whereas synteny of the Y and P genomes was more distorted. The collinearity of 1Y, 2Y, 3Y and 7Y might be interrupted in the Y genome. A new 5S rDNA site on 2Y might be translocated from 1Y. The short arm of 3Y might involve translocated segments from 7Y. The 7 Y was identified as involving a pericentric inversion. A reciprocal translocation between 2P and 4P, and tentative structural aberrations in the subtelomeric region of 1PL and 4PL, were observed in the P genome. Chromosome polymorphisms, which were mostly characterized by repeats amplification and deletion, varied between chromosomes, genomes, and different populations. However, two translocations involving a P genome segmental in 3YL and a non-Robertsonial reciprocal translocation between 4Y and 3P were identified in two independent populations. Moreover, the proportion of heterozygous karyotypes reached almost 35% in all materials, and almost 80% in the specific population. These results provide new insights into the genome organization of K.hirsuta and will facilitate genome dissection and germplasm utilization of this species.

Background: Yaks (Bos grunniens) are a livestock species that is highly adapted to the extremely conditions of the Qinghai-Tibet plateau. Heteroplasmy and nuclear-mitochondrial DNA have been reported in many species, but are still unknown in yaks. The diversity of D-loop sequences, derived from the sequencing of PCR products, provides widely-used maternal DNA markers for the study of yak population and biology. D-loop variations were examined by sequencing the mono clones of the PCR products from individuals, and a comparative analysis with other documented PCR-product based sequences was conducted.Results: Twenty-two and 27 variants were detected in 25 and 38 clones in two different yak individuals, respectively. Phylogenetic analysis in each demonstrated that variants could be grouped into two distinct major clades individual. Analysis of the D-loop sequences of domesticated yaks and wild yaks (Bos grunniens mutus) from the gene bank, which were originally obtained by sequencing of the PCR products, also revealed the two distinct clades. Integrative analysis of all the above variants indicated two major distinct clades, consistent with the respective analysis. One common variant was revealed to be shared by the differently sourced sequences. Furthermore, consensus comparison of all clone sequences revealed 13 differential sites between the two major clades, which are still strongly conserved in sequences from the gene bank. A few recombination events were detected between individual variants, and the supposed recombinants displayed distinct phylogenetic divergence from those in the same clade. Conclusion: Highly varied D-loop sequences were detected in the individual yaks. The detected variants were clustered into two deeply divergent clades as the haplotypes reported by other researchers employing PCR-product based D-loop sequences. This suggests either or both of heteroplasmy and nuclear-mitochondrial DNA in yaks, and also emphasizes the need for reconsidering D-loop sequences as haploid and matrilineal markers for phylogenetic analysis in yaks.

Siberian wild rye (Elymus sibiricus L.), an allotetraploid species, is a potentially high-quality perennial forage crop native to temperate regions. We used fluorescently conjugated oligonucleotides, representing ten repetitive sequences, including 6 microsatellite repeats, two satellite repeats, and two ribosomal DNAs, to characterize E. sibiricus chromosomes, using sequential fluorescence in situ hybridization and genomic in situ hybridization assays. Our results showed that microsatellite repeats (AAG)10 or (AGG)10, satellite repeats pAs1 and pSc119.2, and ribosomal 5S rDNA and 45S rDNA are specific markers for unique chromosomes. A referable karyotype ideogram was suggested, by further polymorphism screening, across different E. sibiricus cultivars with a probe mixture of (AAG)10, Oligo-pAs1, and Oligo-pSc119.2. Chromosomal polymorphisms vary between different genomes and between different individual chromosomes. In particular, two distinct forms of chromosome E in H genome were identified in intra- and inter-populations. Here, the significance of these results, for E. sibiricus genome research and breeding, and novel approaches to improve fluorescence in situ hybridization-based karyotyping are discussed.

The karyotypes of 27 individuals of Elymus nutans from eight wild populations in the Qinghai Plateau were analyzed using sequential FISH and GISH. High FISH pattern polymorphism and karyotype variation were detected within and among populations. The chromosome variations were mainly characterized as repeat deletions and amplifications along with inter-genomic translocations. The chromosomes of the St and Y genomes demonstrated higher polymorphism than those of the H genome. Six different inter-genomic translocations were identified in 33.3% of individuals; type I and II translocations were detected with higher frequency. Further analysis revealed that type I and II translocations were distributed in different geographic regions. The origin of high karyotype variation of E. nutans in the Qinghai plateau is further discussed.

In most eukaryotic species, centromeres harbor large arrays of tandem repeated satellite DNA sequences. In this study, we report on the genomic distribution of a centromere satellite repeat “MtR3” in Medicago genus and three distantly related genera. Fluorescence in situ hybridization (FISH) results showed MtR3 repeats were detected in the centromere regions in M. truncatula, M. minima, M. edgeworthii, M. ruthenica, M. caerulea, M. sativa, and M. falcata (4×), but no signals were discovered in M. lupulina, M. polymorpha, and M. falcata (2×), Melilotus officinalis, Crotalaria medicaginea, and Trifolium repens. However, sequence analysis showed this MtR3 DNA had genomic distribution in all species and was highly conserved across the entire Medicago genus and three other genera. The conservation and widespread presence suggested MtR3 repeats may play important roles in centromeric function.

Background Polyploidy plays an important role in the adaptation and speciation of plants. The alteration of karyotype is a significant event during polyploidy formation. The Medicago sativa complex includes both diploid (2n = 2× = 16) and tetraploid (2n = 2× = 32) subspecies. The tetraploid M. ssp. sativa was regarded as having a simple autopolyploid origin from diploid ssp. caerulea, whereas the autopolyploid origin of tetraploid ssp. falcata from diploid form ssp. falcata is still in doubt. In this study, detailed comparative cytogenetic analysis between diploid to tetraploid species, as well as genomic affinity across different species in the M. sativa complex, were conducted based on comparative mapping of 11 repeated DNA sequences and two rDNA sequences by a fluorescence in situ hybridization (FISH) technique. Results FISH patterns of the repeats in diploid subspecies caerulea were highly similar to those in tetraploid subspecies sativa. Distinctly different FISH patterns were first observed in diploid ssp. falcata, with only centromeric hybridizations using centromeric and multiple region repeats and a few subtelomeric hybridizations using subtelomeric repeats. Tetraploid subspecies falcata was unexpectedly found to possess a highly variable karyotype, which agreed with neither diploid ssp. falcata nor ssp. sativa. Reconstruction of chromosome-doubling process of diploid ssp. caerulea showed that chromosome changes have occurred during polyploidization process. Conclusions The comparative cytogenetic results provide reliable evidence that diploid subspecies caerulea is the direct progenitor of tetraploid subspecies sativa. And autotetraploid ssp. sativa has been suggested to undergo a partial diploidization by the progressive accumulation of chromosome structural rearrangements during evolution. However, the tetraploid subspecies falcata is far from a simple autopolyploid from diploid subspecies falcata although no obvious morphological change was observed between these two subspecies. Electronic supplementary material The online version of this article (doi:10.1186/s12862-017-0951-x) contains supplementary material, which is available to authorized users.

The St genome, originating from Pseudoroegneria (Nevski) Á. Löve, plays an important role in Triticeae. In this study, the Pseudoroegneria stipifolia genome (2n = 2x = 14, StSt) was screened to identify sequences that could be used for FISH. A total of 163 effective clones were obtained from the genomic plasmid library which was constructed by DNase I digestion of P. stipifolia nuclear genomic DNA. Analysis of these clones identified 112 with characteristics of transposable elements (TEs), 13 with characteristics of tandem repetitive sequences, 8 with characteristics of mRNA sequences, and 30 unknown sequences. Fluorescent signals were detected for 11 of 41 TE sequences on P. stipifolia chromosomes after in situ hybridization and were divided into 4 types according to signal distribution patterns: over the whole St genome chromosomes, telomere to pericentromeric regions, centromere to pericentromeric regions, and terminal regions. The affinity between St and Y genomes was studied using the 11 TE probes in 3 StStYY species. Five TE probes showed no obvious difference between subgenomes, 2 probes displayed divergence only in 2 StStYY species, and 4 probes exhibited significant differences among 3 StStYY species. These results provide a preliminary understanding of the sequence composition of the St genome and enabled 11 novel TE probes to be developed and applied.

Molecular karyotypes of Hordeum bogdanii Wilensky, 1918 (2n = 14), and Hordeum brevisubulatum Link, 1844 ssp. brevisubulatum (2n = 28), were characterized by physical mapping of several repetitive sequences. A total of 18 repeats, including all possible di- or trinucleotide SSR (simple sequence repeat) motifs and satellite DNAs, such as pAs1, 5S rDNA, 45S rDNA, and pSc119.2, were used as probes for fluorescence in situ hybridization on root-tip metaphase chromosomes. Except for the SSR motifs AG, AT and GC, all the repeats we examined produced detectable hybridization signals on chromosomes of both species. A detailed molecular karyotype of the I genome of Hordeum bogdanii is described for the first time, and each repetitive sequence is physically mapped. A high degree of chromosome variation, including aneuploidy and structural changes, was observed in Hordeum brevisubulatum. Although the distribution of repeats in the chromosomes of Hordeum brevisubulatum is different from that of Hordeum bogdanii, similar patterns between the two species imply that the autopolyploid origin of Hordeum brevisubulatum is from a Hordeum species with an I genome. A comparison of the I genome and the other Hordeum genomes, H, Xa and Xu, shows that colocalization of motifs AAC, ACT and CAT and colocalization of motifs AAG and AGG are characteristic of the I genome. In addition, we discuss the evolutionary significance of repeats in the genome during genome differentiation.

The protein content and its type are principal factors affecting wheat (Triticum aestivum) end product quality. Among the wheat proteins, glutenin proteins, especially, high molecular weight glutenin subunits (HMW-GS) are major determinants of processing quality. Wheat and its primary gene pool have limited variation in terms of HMW-GS alleles. Wild relatives of wheat are an important source of genetic variation. For improvement of wheat processing quality its wild relative Thinopyrum elongatum with significant potential was utilized. An attempt was made to replace Th. elongatum chromosome long arm (1EL) carrying HMW-GS genes related to high dough strength with chromosome 1AL of wheat with least or negative effect on dough strength while retaining the chromosomes 1DL and 1BL with a positive effect on bread making quality. To create chromosome specific translocation line [1EL(1AS)], double monosomic of chromosomes 1E and 1A were created and further crossed with different cultivars and homoeologous pairing suppressor mutant line PhI. The primary selection was based upon glutenin and gliadin protein profiles, followed by sequential genomic in situ hybridization (GISH) and fluorescent in situ hybridization (FISH). These steps significantly reduced time, efforts, and economic cost in the generation of translocation line. In order to assess the effect of translocation on wheat quality, background recovery was carried out by backcrossing with recurrent parent for several generations and then selfing while selecting in each generation. Good recovery of parent background indicated the development of almost near isogenic line (NIL). Morphologically also translocation line was similar to recipient cultivar N61 that was further confirmed by seed storage protein profiles, RP-HPLC and scanning electron microscopy. The processing quality characteristics of translocation line (BC4F6) indicated significant improvement in the gluten performance index (GPI), dough mixing properties, dough strength, and extensibility. Our work aims to address the challenge of limited genetic diversity especially at chromosome 1A HMW-GS locus. We report successful development of chromosome 1A specific translocation line of Th. elongatum in wheat with improved dough strength.

Genomes of ten species of Elymus, either presumed or known as tetraploid StY, were characterized using fluorescence in situ hybridization (FISH) and genomic in situ hybridization (GISH). These tetraploid species could be grouped into three categories. Type I included StY genome reported species—Roegneria pendulina, R. nutans, R. glaberrima, R. ciliaris, and Elymus nevskii, and StY genome presumed species—R. sinica, R. breviglumis, and R. dura, whose genome could be separated into two sets based on different GISH intensities. Type I genome constitution was deemed as putative StY. The St genome were mainly characterized with intense hybridization with pAs1, fewer AAG sites, and linked distribution of 5S rDNA and 18S-26S rDNA, while the Y genome with less intense hybridization with pAs1, more varied AAG sites, and isolated distribution of 5S rDNA and 18S-26S rDNA. Nevertheless, further genomic variations were detected among the different StY species. Type II included E. alashanicus, whose genome could be easily separated based on GISH pattern. FISH and GISH patterns suggested that E. alashanicus comprised a modified St genome and an unknown genome. Type III included E. longearistatus, whose genome could not be separated by GISH and was designated as StlYl. Notably, a close relationship between Sland Ylgenomes was observed.

PpCR-1 monomer hunting from the amplified sequence by designated primers of clone 6. Figure S2. PpTR-1 monomer hunting from the amplified sequence by designated primers of clone 1. Figure S3. PpTR-2 monomer hunting from the amplified sequence by designated primers of clone 23. Figure S4. PpTR-3 monomer hunting from the amplified sequence by designated primers of clone 94. (DOC 44Â kb)

Figure S1-S6. (PPTX 2091 kb)

Siberian wildrye, Elymus sibiricus L., is an important perennial forage crop in temperate regions of the world, especially in the Qinghai–Tibet plateau. However, it is now threatened by climate warming, excessive grazing, and damage to its natural habitat. A total of 53 polymorphic genomic-SSR markers were isolated and characterized in E. sibiricus. The number of alleles for these markers in 11 individuals varied from 2 to 5, with an average of 3.09 alleles per locus. Segregation analysis in an F2 population revealed that the tested genomic-SSR markers had a co-dominant nature and Mendelian inheritance. Cross-species amplification tests showed that about half of the total E. sibiricus genomic-SSR markers could be effectively amplified in E. nutans. These SSR markers are the first characterized in E. sibiricus and will be useful for investigating genetic diversity and molecular-assisted breeding.

Poa pratensis L. is an important perennial grass used both for forage and turf in temperate regions of the world. In this study, we isolated and characterized 15 novel polymorphic genomic simple sequence repeat (SSR) markers in P.pratensis. The polymorphism of each marker was assessed in 14 cultivars. The number of alleles of individual microsatellites ranged from three to six, with an average of 3.8 alleles per SSR. Cross-species amplification tests showed that 13 and seven of the characterized P.pratensis markers could be effectively amplified in P.pratensis var. anceps Gaud and P.crymophila Keng, respectively. These polymorphic microsatellite markers should serve as powerful tools for the investigation of genetic diversity and related analyses, and also for molecular-assisted breeding of P.pratensis.

Eleven tandemly repetitive sequences were identified from a Cot-1 library by FISH and sequence analysis of alfalfa (Medicago sativa). Five repetitive sequences (MsCR-1, MsCR-2, MsCR-3, MsCR-4, and MsCR-5) were centromeric or pericentromeric, of which three were satellite DNAs and two were minisatellite DNAs. Monomers of 144, 148, and 168 bp were identified in MsCR-1, MsCR-2, and MsCR-3, respectively, while 15 and 39 bp monomers were identified in MsCR-4 and MsCR-5, respectively. Three repetitive sequences were characterized as subtelomeric; one repetitive sequence, MsTR-1, had a 184 bp monomer, and two repetitive sequences had fragments of 204 and 327 bp. Sequence analysis revealed homology (70-80 %) between MsTR-1 and a highly repeated sequence (C300) isolated from M. ssp. caerulea. Three identified repetitive sequences produced hybridization signals at multiple sites in a few of the chromosomes; one repetitive sequence was identified as the E180 satellite DNA previously isolated from M. sativa, while the other 163 and 227 bp fragments had distinct sequences. Physical mapping of the repetitive sequences with double-target FISH revealed different patterns. Thus, nine novel tandemly repetitive sequences that can be adopted as distinct chromosome markers in alfalfa were identified in this study. Furthermore, the chromosome distribution of each sequence was well described. Though significant chromosome variations were detected within and between cultivars, a molecular karyotype of alfalfa was suggested with the chromosome markers we identified. Therefore, these novel chromosome markers will still be a powerful tool for genome composition analysis, phylogenetic studies, and breeding applications.

Background Poa pratensis L. is a turf grass and forage crop used worldwide. Being a facultative apomictic species, P. pratensis has a highly variable chromosome number. Chromosomal markers constitute a powerful tool for chromosome identification and for various aspects of genomic research. However, currently, no chromosomal markers are available for P. pratensis. Results Four novel chromosome markers were isolated from a screen of Cot-1 DNA libraries, combined with fluorescence in situ hybridization (FISH) in Poa pratensis. Three tandemly repetitive sequences (PpTR-1, PpTR-2, and PpTR-3) were characterized as subtelomeric. Monomers of 318 bp, 189 bp and 189 bp were identified in PpTR-1, PpTR-2, and PpTR-3, respectively. One tandemly repetitive sequence (PpCR-1) was shown to be centromeric or pericentromeric, and it had a monomer of 27 bp. The distribution patterns of PpTR-1, PpTR-2, and PpTR-3 were highly conserved across different P. pratensis cultivars and in the distantly related Poa species, whereas PpCR-1 was conserved across different P. pratensis cultivars, but less conserved across Poa species. Conclusion In this study, we report the identification and characterization of four novel chromosomal markers in P. pratensis. These chromosomal markers are powerful tools for accurate assessment of chromosome count, genomic and phylogenetic analyses, as well as studies of apomixis in P. pratensis. Electronic supplementary material The online version of this article (doi:10.1186/s13039-017-0307-7) contains supplementary material, which is available to authorized users.

Wild Triticeae grasses serve as important gene pools for forage and cereal crops. Based on DNA sequences of genome-specific RAPD markers, sequence-tagged site (STS) markers specific for W and Y genomes have been obtained. Coupling with the use of genomic in situ hybridization, these STS markers enabled the identification of the W- and Y-genome chromosomes in backcross derivatives from hybrids of bread wheat Triticum aestivum L. (2n = 42; AABBDD) and Elymus rectisetus (Nees in Lehm.) Á. Löve & Connor (2n = 42; StStWWYY). The detection of six different alien chromosomes in five of these derivatives was ascertained by quantitative PCR of STS markers, simple sequence repeat markers, rDNA genes, and (or) multicolor florescence in situ hybridization. Disomic addition line 4687 (2n = 44) has the full complement of 42 wheat chromosomes and a pair of 1Y chromosomes that carry genes for resistance to tan spot (caused by Pyrenophora tritici-repentis (Died.) Drechs.) and Stagonospora nodorum blotch (caused by Stagonospora nodorum (Berk.) Castellani and Germano). The disomic addition line 4162 has a pair of 1St chromosomes and 21 pairs of wheat chromosomes. Lines 4319 and 5899 are two triple substitution lines (2n = 42) having the same chromosome composition, with 2A, 4B, and 6D of wheat substituted by one pair of W- and two pairs of St-genome chromosomes. Line 4434 is a substitution–addition line (2n = 44) that has the same W- and St-genome chromosomes substituting 2A, 4B, and 6D of wheat as in lines 4319 and 5899 but differs by having an additional pair of Y-genome chromosome, which is not the 1Y as in line 4687. The production and identification of these alien cytogenetic stocks may help locate and isolate genes for useful agronomic traits.

Genome constitution and genetic relationships between six Elymus species were assessed by physical mapping of different repetitive sequences using a technique of sequential fluorescence in situ hybridization and genomic in situ hybridization. The six Elymus species are all naturally growing species in northwest China, namely, E. sibiricus, E. nutans, E. barystachyus, E. xiningensis, E. excelsus, and E. dahuricus. An StStHH genome constitution was revealed for E. sibiricus and StStHHYY for the remainder species. Each chromosome could be clearly characterized by physical mapping with 18S-26S rDNA, 5S rDNA, Afa-family, and AAG repeats, and be allocated to a certain genome by genomic in situ hybridization. Two 5S rDNA sites, each in the H and St genomes, and three 18S-26S rDNA sites, two in the St genome and one in the Y genome, were uncovered in most of the species. The strong Afa-family hybridization signals discriminated the H genome from the St and Y genomes. The H and Y genome carried more AAG repeats than St. A common non-Robertsonian reciprocal translocation between the H and Y genomes was revealed in E. barystachyus, E. xiningensis, E. excelsus and E. dahuricus. Comparison of molecular karyotypes strongly suggests that they can be classified into three groups, namely, E. sibiricus, E. nutans, and others.

Elymus nutans L. (StHY, 2n = 6x = 42) is extensively selected from the natural population and domesticated as perennial grass forage in the Qinghai-Tibet plateau in China due to its high tolerance to environmental stresses, such as cold and drought. Karyotyping was conducted in 12 randomly selected plants by sequential fluorescence in situ hybridization (FISH) and genomic in situ hybridization (GISH). GISH discriminated St, H and Y genomes, indicating that E. nutans has retained its ancestral genome, and large chromosomal rearrangements have not occurred. However, FISH using an AGG satellite and Afa-family repetitive sequences, revealed marked variation in the signalling patterns of most of the chromosomes. Many of the plants carried chromosomes with a specific pattern in the homozygous state, indicating that self-pollination or sib-crossing occurs in small populations during selection for domestication. In addition, several intergenomic translocations appeared, possibly caused by homoeologous chromosome recombination. The nature of the polymorphisms seen in the chromosomes of the domesticated Population of E. nutans is discussed.

A monosomic addition line of Aegilops tauschii chromosome 1D in Triticum durum cv. PBW114 was produced in 1990. This line was self-pollinated and maintained for several generations while following the presence of chromosome 1D carrying the gene for red glume color. Cytological analysis indicated that two of the three derivative lines had substitution of chromosome 1D for 1A and another had substitution of chromosome 1D for 1B. One of these lines carried a pair of small chromosomes in addition to the 1D chromosome. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the derived lines showed the presence of high-molecular-weight (HMW) glutenin encoded by the Glu-D1 locus. The small chromosome found in one of the lines had nearly regular pairing and transmission to daughter nuclei. Fluorescent in situ hybridization (FISH) and analysis of molecular markers indicated that the small chromosome was derived from the short arm of chromosome 1A and carried the Glu-A3 locus. Microsatellite mapping based on the deletion bin map revealed that the small chromosome had terminal deletions on both the terminal and centromeric sides. The line with the small chromosome showed improvement of the sodium dodecyl sulfate (SDS)-sedimentation value as compared to parent durum. However, the increase in SDS-sedimentation value was more significant in the substitution line of chromosome 1D for 1A without the small chromosome. These facts suggest a negative effect of the Glu-A3 locus on dough strength. The sequence of the Glu-D1 locus from these lines showed that the HMW glutenin subunits were Ae. tauschii specific 2(t) + T2, which were previously found to be associated with poor rheological properties and bread loaf volume in synthetic hexaploid wheat by other workers. Thus, the significant improvement in the SDS-sedimentation value of the substitution line of 1D for 1A suggests that the absence of the negative effect of chromosome 1A on quality is more important than the presence of Glu-D1 of Ae. tauschii.

The genome compositions and genetic relationships of seven species of Kengyilia were assessed using a sequential fluorescence in situ hybridization (FISH) and genomic in situ hybridization (GISH) technique. Five species, K. kokonorica, K. rigidula, K. hirsuta, K. grandiglumis, and K. thoroldiana, are native to Qinghai (China). The other two, K. alatavica and K. batalinii, are distributed in Xinjiang (China) and Kyrgyzstan, respectively. Each chromosome could be easily identified using chromosome markers (45S rDNA, 5S rDNA, pAs1, and AAG repeats) by FISH and allocated to the St, P, or Y genome by GISH. Molecular karyotype comparison indicated that K. alatavica and K. batalinii were distinct from the Qinghai species in all three genomes. These results support that the species of Kengyilia from Central Asia and the Qinghai–Tibetan plateau have independent origins. Genomic differentiation was still detected among the species of Kengyilia from Qinghai. Specifically, a common species-specific pericentric inversion was identified in both K. grandiglumis and K. thoroldiana, and an identical St-P non-Robertsonian translocation was frequently detected in K. hirsuta. The Qinghai species formed three genetic groups, K. kokonorica–K. rigidula, K. hirsuta, and K. grandiglumis–K. thoroldiana. The possible role of species-specific inversions and translocations in the evolution of StPY species is discussed.

Psathyrostachys huashanica Keng (2n = 14; N(h)N(h)) is an endangered wheat-related species, with a distribution in the Huashan region of central China. It has many agronomically promising characters including resistance to disease and drought and winter hardiness. We produced hybrids between common wheat as the female parent and P. huashanica as the male parent. From the offspring, we selected chromosome addition lines of common wheat carrying each of all seven chromosomes of P. huashanica. Four chromosomes (B, D, E and F) were recovered in disomic lines and three (A, C and G) in monosomic addition lines. These alien chromosomes were distinguished from each other by cytological analyses. Chromosome A was characterized by a 45S rDNA site in the subtelomeric region of the short arm. Chromosome B carried one 5S and one 45S rDNA sites co-localized in an interstitial region of the short arm, and the expression of the alien high-molecular-weight glutenin was observed in the endosperm of line B. Chromosome D had a 45S rDNA signal in the interstitial region of the long arm. Chromosomes C, E, and F were distinguished by the EST-SSR markers Ltc0464, Ltc0096, and Xcfe175, respectively. The homoeologous group of each alien chromosome was implied from the results above, and the utilization of these addition lines for wheat breeding was discussed.

Genome characterization of 14 hexaploid lines that spontaneously appeared in octoploid Triticales was carried out by sequential genomic in situ hybridization and fluorescence in situ hybridization, high molecular weight glutenin subunits and SSR marker analyses. All of the lines showed a chromosome constitution of complete A and B genomes, and a composite genome consisting of the chromosomes of D and R genomes. The composite genome of the 11 lines consisted of chromosomes 1R, 2D, 3R, 4R, 5R, 6R and 7R, that of the two lines were 1D, 2D, 3R, 4R, 5R, 6R and 7R, and that of one line was 1R, 2D, 3R, 4R, 5R, 6D and 7R. The incompatibility of the D and R genomes in common wheat genetic background, preferential retention of chromosome 2D and importance of these lines for the development of hexaploid Triticale are discussed in this report.

Genomic constitutions of three taxa of Hystrix Moench, H. patula, H. duthiei ssp. duthiei and H. duthiei ssp. longearistata, were examined by meiotic pairing behavior and genomic in-situ hybridization. Meiotic pairing in hybrids of H. patula x Pseudoroegneria spicata (St), H. patula x Elymus wawawaiensis (StH), H. patula x H. duthiei ssp. longearistata, H. patula x Psathyrostachys huashanica (Ns ( h )), H. duthiei ssp. duthiei x Psa. huashanica, H. duthiei ssp. longearistata x Psa. huashanica, Leymus multicaulis (NsXm) x H. duthiei ssp. longearistata averaged 6.53, 12.83, 1.32, 0.29, 5.18, 5.11 and 10.47 bivalents per cell, respectively. The results indicate that H. patula has the StH genome and H. duthiei ssp. duthiei and H. duthiei ssp. longearistata have the NsXm genome. Results of genomic in-situ hybridization analysis strongly supported the chromosome pairing data; therefore it is concluded that the type species of Hystrix, H. patula, should be included in Elymus, and that H. duthiei ssp. duthiei and H. duthiei ssp. longearistata should be transferred to Leymus.

Poa pratensis L. is a turf grass and forage crop used worldwide. Being a facultative apomictic species, P. pratensis has a highly variable chromosome number. Chromosomal markers constitute a powerful tool for chromosome identification and for various aspects of genomic research. However, currently, no chromosomal markers are available for P. pratensis. Four novel chromosome markers were isolated from a screen of Cot-1 DNA libraries, combined with fluorescence in situ hybridization (FISH) in Poa pratensis. Three tandemly repetitive sequences (PpTR-1, PpTR-2, and PpTR-3) were characterized as subtelomeric. Monomers of 318 bp, 189 bp and 189 bp were identified in PpTR-1, PpTR-2, and PpTR-3, respectively. One tandemly repetitive sequence (PpCR-1) was shown to be centromeric or pericentromeric, and it had a monomer of 27 bp. The distribution patterns of PpTR-1, PpTR-2, and PpTR-3 were highly conserved across different P. pratensis cultivars and in the distantly related Poa species, whereas PpCR-1 was conserved across different P. pratensis cultivars, but less conserved across Poa species. In this study, we report the identification and characterization of four novel chromosomal markers in P. pratensis. These chromosomal markers are powerful tools for accurate assessment of chromosome count, genomic and phylogenetic analyses, as well as studies of apomixis in P. pratensis.