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Wheat powdery mildew is a destructive disease seriously threatening yield and quality. Comprehensive dissection of new resistance-related loci/genes is necessary to control this disease. LS5082 is a Chinese wheat breeding line with resistance to powdery mildew. Genetic analysis indicated that a single dominant gene, tentatively designated PmLS5082, conferred seedling resistance to different Bgt isolates. Bulked segregant RNA-seq (BSR-seq) was carried out to map the R gene PmLS5082 and profile differentially expressed genes associated with PmLS5082. PmLS5082 was mapped to chromosome arm 2BL and flanked by the markers WGGBH612-5 and YTU19-005 with genetic distances of 0.3 and 0.4 cM, respectively. The physical position was subsequently locked into the interval of 710.3-711.0 Mb. PmLS5082 differs from the catalogued Pm genes on chromosome arm 2BL in its resistant spectrum, physical position and origin, suggesting it is most likely a new Pm gene. Through COG and KEGG analysis, differentially expressed genes associated with PmLS5082 were profiled, and six genes in PmLS5082 interval were confirmed to be associated with PmLS5082 via RT-qPCR, using an additional set of wheat samples and time-course analysis post-inoculation with Bgt. In order to transfer PmLS082 to different genetic backgrounds using marker-assisted selection (MAS), closely linked markers, including Kompetitive Allele-Specific PCR (KASP) markers, were evaluated and nine markers were confirmed to be widely applicable for MAS in different genetic backgrounds.

The present study investigated 5S and 45S rDNA sites in six Fritillaria species. All species were diploid with 2n = 2x = 24 chromosomes. One, three, or four B chromosomes (Bs) were detected in F. assyriaca ecotypes. Another two B- chromosomes were observed for F. zagrica. One to two pairs of 5S rDNA sites were observed in terminal or sub-terminal chromosomal regions. The number of 45S rDNA sites was one pair in F. raddeana, three in F. assyriaca, F. zagrica, and F. persica, four in F. avromanica, and eight in F. chlorantha. Most of the 45S rDNA sites were distal except for F. raddeana with a pair in interstitial and F. chlorantha with two pairs in sub-terminal locations. Chromosome and karyotype indices were identified, F. avromanica and F. chlorantha as the species with the most symmetrical and asymmetrical chromosomes, respectively. Cluster analysis of the karyotype similarity matrix showed that the number and distribution of the observed rDNA sites were not congruent with the taxonomy of species in the defined subgenus entirely. Particularly for F. chlorantha which belongs to the Fritillaria subg.

Nigella is a small genus belonging to the Ranunculaceae family which is presumably originated and distributed in Aegean and the adjacent Western-Irano-Turanian region. Comparative repeat analysis of N. sativa, N. damascena and N. bucharica was performed using low-pass Illumina genomic reads followed by karyotyping and FISH mapping of seven Nigella species using the in silico identified repeats and rDNA probes. High- and moderate-copy repeat sequences occupy 57.52%, 59.01% and 64.73% of N. sativa, N. damascena and N. bucharica genomes, respectively. The majority (47.91% in N. sativa, 39.47% in N. damascena and 51.25% in N. bucharica) of the genomes are retrotransposons (class I transposons), while DNA transposons (class II transposons) contributed to only 1.50%, 1.60% and 2.19% of the genomes. The analyzed Nigella species possess large genomes of about 7.4 to 12.4 Gbp/1C, but only two satellite repeats in N. sativa, one in N. damascena and four in N. bucharica were identified, representing 0.75%, 1.21% and 1.45% of the genomes, respectively. An exceptionally high number of 45S rDNA loci was found in N. hispanica, each chromosome revealed at least one 45S rDNA site and one of them occurs in hemizygous condition. The observed three karyotype groups agreed with the ITS/rbcL-derived phylogeny. The detected variation in chromosome number, type and positioning of satellite repeats and localization of rDNA loci are possibly due to chromosomal rearrangements, rDNA repositioning and copy number changes.

Due to the accumulation of various useful traits over evolutionary time, emmer wheat (Triticum turgidum subsp. dicoccum and dicoccoides, 2n = 4x = 28; AABB), durum wheat (T. turgidum subsp. durum, 2n = 4x = 28; AABB), T. timopheevii (2n = 4x = 28; AAGG) and D genome containing Aegilops species offer excellent sources of novel variation for the improvement of bread wheat (T. aestivum L., AABBDD). Here, we made 192 different cross combinations between diverse genotypes of wheat and Aegilops species including emmer wheat × Ae. tauschii (2n = DD or DDDD), durum wheat × Ae. tauschii, T. timopheevii × Ae. tauschii, Ae. crassa × durum wheat, Ae. cylindrica × durum wheat and Ae. ventricosa × durum wheat in the field over three successive years. We successfully recovered 56 different synthetic hexaploid and octaploid F2 lines with AABBDD, AABBDDDD, AAGGDD, D1D1XcrXcrAABB, DcDcCcCcAABB and DvDvNvNvAABB genomes via in vitro rescue of F1 embryos and spontaneous production of F2 seeds on the Fl plants. Cytogenetic analysis of F2 lines showed that the produced synthetic wheat lines were generally promising stable amphiploids. Contribution of D genome bearing Aegilops and the less-investigated emmer wheat genotypes as parents in the crosses resulted in synthetic amphiploids which are a valuable resource for bread wheat breeding.

In newly formed allopolyploids, meiotic instability in early generations contributes to reduced fertility, but less is known about their mitotic accuracy and somatic instability. Here, the authors report somatic numerical chromosome variation (somatic aneuploidy) among different individuals of newly synthesized wheat–Aegilops triuncialis amphiploids (AABBDDUtUtCtCt genome) over three successive generations. In total, 21 seeds in the F2 to F4 generations descended from three different F1 hybrids (2n = 5x = 35, ABDUtCt genome) were analyzed by chromosome counting and fluorescent in situ hybridization. Somatic aneuploidy was detected in 17 (81%) investigated individuals. Somatic chromosome numbers of the cells (among and within the evaluated individuals) ranged from 62 to 70. Furthermore, flow cytometry revealed variation in genome size within and between individual amphiploids that may be due to variable chromosome numbers. There was no evidence that somatic aneuploidy leads to stable cytotypes, at least in the early generations. The authors conclude that both newly formed status and large genome sizes may contribute to somatic and meiotic instability in synthetic wheat–Aegilops triuncialis amphiploids.

Each species has a typical karyotype, which represents the phenotypic appearance of the somatic chromosomes including number, size, and morphology. Idiogram is a diagrammatic representation of the chromosomes showing their relative size, homologous groups and different cytogenetic landmarks. Chromosomal analysis of cytological preparations is an essential component of many investigations which involves the calculation of karyotypic parameters and generation of idiogram. Although various tools are available for karyotype analysis, here we demonstrate karyotype analysis using our recently developed tool named KaryoMeasure. KaryoMeasure is a semi-automated free and user-friendly karyotype analysis software that facilitates data collection from different digital images of the metaphase chromosome spreads and calculates a wide variety of chromosomal and karyotypic parameters along with the related standard errors. KaryoMeasure draws idiograms of both diploid and allopolyploid species into a vector-based SVG or PDF image file.

We applied fluorescent in situ hybridization (FISH) using (GAA)10 microsatellite repeat alone or in combination with oligo pSc119.2-1, pTa535-1, pAs1-1, 5S and 45S rDNA probes to identify individual chromosomes and produce banded karyotypes for five allopolyploid Aegilops species that were thought to possess M subgenome. Labelling patterns of GAA repeats allow identification of individual chromosomes in the studied species including diploid Ae. comosa subsp. heldreichii (2n = MhMh) and Ae. umbellulata (2n = UU); and allopolyploid Ae. biuncialis (2n = UbUbMbMb), Ae. geniculata (2n = UgUgMgMg), Ae. columnaris (2n = UcUcXcXc), Ae. neglecta (2n = UnUnXnXn) and Ae. crassa (2n = 4x = D1D1XcrXcr and 2n = 6x = D1D1XcrXcrDcrDcr). Intraspecific polymorphisms of GAA labelling patterns were observed between different genotypes in each species. FISH results showed that the X* subgenomes of Ae. columnaris and Ae. neglecta are highly similar, implying that both species originated from a common ancestor. However, these X* subgenomes were also distinct from and more heterochromatic when compared to the M* subgenomes of Ae. biuncialis and Ae. geniculata. This suggests that the X* subgenomes may not have originated from the Ae. comosa, as previously thought. Although (GAA)n bands are relatively few and weak in Ae. tauschii (DD genome), all 4x Ae. crassa (D1D1XcrXcr genome) chromosomes showed distinct GAA patterns. (GAA)10 probe alone was not sufficient for the discrimination of all the chromosomes of 6x Ae. crassa (D1D1XcrXcrDcrDcr), which needs a combination of (GAA)10 with the pTa535-1 or pAs1-1 probes.

Although Ae. tauschii has been extensively utilised for wheat breeding, the D-genome-containing allopolyploids have largely remained unexploited. In this review, we discuss approaches that can be used to exploit the D genomes of the different Aegilops species for the improvement of bread wheat. The D genome of allohexaploid bread wheat (Triticum aestivum, 2n = AABBDD) is the least diverse of the three wheat genomes and is unarguably less diverse than that of diploid progenitor Aegilops tauschii (2n = DD). Useful genetic variation and phenotypic traits also exist within each of the wheat group species containing a copy of the D genome: allopolyploid Aegilops species Ae. cylindrica (2n = DcDcCcCc), Ae. crassa 4x (2n = D1D1XcrXcr), Ae. crassa 6x (2n = D1D1XcrXcrDcrDcr), Ae. ventricosa (2n = DvDvNvNv), Ae. vavilovii (2n = D1D1XcrXcrSvSv) and Ae. juvenalis (2n = D1D1XcrXcrUjUj). Although Ae. tauschii has been extensively utilised for wheat breeding, the D-genome-containing allopolyploids have largely remained unexploited. Some of these D genomes appear to be modified relative to the bread wheat and Ae. tauschii D genomes, and others present in the allopolyploids may also contain useful variation as a result of adaptation to an allopolyploid, multi-genome environment. We summarise the genetic relationships, karyotypic variation and phenotypic traits known to be present in each of the D genome species that could be of relevance for bread wheat improvement and discuss approaches that can be used to exploit the D genomes of the different Aegilops species for the improvement of bread wheat. Better understanding of factors controlling chromosome inheritance and recombination in wheat group interspecific hybrids, as well as effective utilisation of new and developing genetics and genomics technologies, have great potential to improve the agronomic potential of the bread wheat D genome.

The species of Pimpinella, one of the largest genera of the family Apiaceae, are traditionally cultivated for medicinal purposes. In this study, high-throughput double digest restriction-site associated DNA sequencing technology (ddRAD-seq) was used to identify single nucleotide polymorphisms (SNPs) in eight Pimpinella species from Iran. After double-digestion with the enzymes HpyCH4IV and HinfI, a total of 334,702,966 paired-end reads were de novo assembled into 1,270,791 loci with an average of 28.8 reads per locus. After stringent filtering, 2440 high-quality SNPs were identified for downstream analysis. Analysis of genetic relationships and population structure, based on these retained SNPs, indicated the presence of three major groups. Gene ontology and pathway analysis were determined by using comparison SNP-associated flanking sequences with a public non-redundant database. Due to the lack of genomic resources in this genus, our present study is the first report to provide high-quality SNPs in Pimpinella based on a de novo analysis pipeline using ddRAD-seq. This data will enhance the molecular knowledge of the genus Pimpinella and will provide an important source of information for breeders and the research community to enhance breeding programs and support the management of Pimpinella genomic resources.

Salinity stress is one of the major plant growth-limiting factors in agriculture. It causes ionic imbalance, thus decrease the growth and yield attributes of crops especially wheat. Seedling stage is considered as one of the most sensitive stages under salinity stress. Survival of seeds at seedling stage can overcome the adverse impacts of salinity stress to some extent. Selection of salt tolerant varieties in seedling stage is considered as an effective strategy. Hence, current study was conducted to examine the seed germination responses of four wheat varieties under different levels of salinity. The wheat varieties such as ‘Rakhshan’, ‘Sirvan’, ‘Pishgam’ and ‘Heidari’ were grown and four salinity levels of 0, 4, 8 and 12 dS/m were applied under completely randomized design. The varieties such as ‘Sirvan’, ‘Rakhshan’ and ‘Heidari’ showed significant response for germination compared to ‘Pishgam’ at 12 dS/m salinity. Furthermore, the variety ‘Rakhshan’ showed significantly higher germination rate (20.3%), higher root length (33.4%) and higher shoot length (84.3%) than ‘Pishgam’, ‘Sirvan’ and ‘Sirvan’ respectively. However, contrasting results were obtained for dry weight of seedlings where 12.2% increase was observed in ‘Pishgam’ over ‘Rakhshan’ at 12 dS/m salinity that might be due to higher capability to uptake of Na and Cl ions. In conclusion, ‘Rakhshan’ wheat variety proved to be the most salinity tolerant as it grew better under saline soil conditions. More investigations at field level are recommended to declare ‘Rakhshan’ as salinity tolerant cultivar.

Amine oxidases (AOs) including copper containing amine oxidases (CuAOs) and FAD-dependent polyamine oxidases (PAOs) are associated with polyamine catabolism in the peroxisome, apoplast and cytoplasm and play an essential role in growth and developmental processes and response to biotic and abiotic stresses. Here, we identified PAO genes in common wheat (Triticum aestivum), T. urartu and Aegilops tauschii and reported the genome organization, evolutionary features and expression profiles of the wheat PAO genes (TaPAO). Expression analysis using publicly available RNASeq data showed that TaPAO genes are expressed redundantly in various tissues and developmental stages. A large percentage of TaPAOs respond significantly to abiotic stresses, especially temperature (i.e. heat and cold stress). Some TaPAOs were also involved in response to other stresses such as powdery mildew, stripe rust and Fusarium infection. Overall, TaPAOs may have various functions in stress tolerances responses, and play vital roles in different tissues and developmental stages. Our results provided a reference for further functional investigation of TaPAO proteins.

An interesting and possibly unique pattern of genome evolution following polyploidy can be observed among allopolyploids of the Triticum and Aegilops genera (wheat group). Most polyploids in this group are presumed to share a common unaltered (pivotal) subgenome (U, D, or A) together with one or two modified (differential) subgenomes, a status that has been referred to as 'pivotal-differential' genome evolution. In this review we discuss various mechanisms that could be responsible for this evolutionary pattern, as well as evidence for and against the putative evolutionary mechanisms involved. We suggest that, in light of recent advances in genome sequencing and related technologies in the wheat group, the time has come to reopen the investigation into pivotal-differential genome evolution.

Development of wheat–alien translocation lines has facilitated practical utilization of alien species in wheat improvement. The production of a compensating Triticum aestivum–Thinopyrum bessarabicum whole-arm Robertsonian translocation (RobT) involving chromosomes 6D of wheat and 6Eb of Th. bessarabicum (2n = 2x = 14, EbEb) through the mechanism of centric breakage–fusion is reported here. An F2 population was derived from plants double-monosomic for chromosome 6D and 6Eb from crosses between a DS6Eb(6D) substitution line and bread wheat cultivar ‘Roushan’ (2n = 6x = 42, AABBDD) as female parent. Eighty F2 genotypes (L1–L80) were screened for chromosome composition. Three PCR-based Landmark Unique Gene (PLUG) markers specific to chromosomes 6D and 6Eb were used for screening the F2 plants. One plant with a T6EbS.6DL centric fusion (RobT) was identified. A homozygous translocation line with full fertility was recovered among F3 families and verified with genomic in situ hybridization (GISH). Grain micronutrient analysis showed that the DS6Eb(6D) substitution line and T6EbS.6DL stock have higher Fe and Zn contents than the recipient wheat cultivar ‘Roushan’.

The cultivation of emmer wheat (Triticum dicoccon Schrank) in Iran has been decreased and limited to the marginal agricultural lands of western parts of the country. In the present study, 40 emmer wheat accessions including 13 Iranian landraces and 27 wild and domesticated accessions obtained from CIMMYT, were evaluated for genetic diversity using 24 SSR and four EST-SSR markers, distributed over all the chromosomes. The number of detected alleles was 168 (for all the studied accessions) and 84 (for the Iranian landraces), with average polymorphic information contents of 0.61 and 0.30, respectively. Based on the allelic information and cluster analysis, wild emmer wheats were more variable than domestic emmers and the Iranian emmer landraces had low genetic variability making an isolated cluster distinct from the domesticated emmers of Transcaucasia. The low genetic diversity in Iranian emmer landraces may be due to genetic drift and decreased cultivation area during the past years proving a need to manage emmer wheat genetic resources in Iran towards increasing its genetic diversity, breeding and conservation.

Black cumin (Nigella sativa) is a medicinal herb belongs to the Ranunculacea which raised attention due to its pharmaceutical properties. Medical significance of N. sativa mainly attributed to its oxygenated monoterpenes and triterpene saponins which are biosynthesized via the methyl erythritol phosphate (MEP) and MVA (mevalonic acid) pathways, respectively. In order to improve our understanding of monoterpene and triterpene metabolism the partial sequence of a hypothetical monoterpene synthase (MTS) was isolated from N. sativa for the first time and subsequently the relative gene expression of two genes of monoterpene metabolism including geranyl diphosphate synthase (GDS), the isolated monoterpene synthase (MTS) and two genes of triterpene saponins biosynthesis including squalene epoxidase (SQE) and β- amyrin synthase (βAS) were monitored in response to two universal abiotic elicitors including methyl jasmonate (MJ) and salicylic acid (SA), also in different tissues of N. sativa including leaves, stems, roots, capsules and immature seeds. Results of semi quantitative reverse transcription PCR revealed differential regulation of these genes in N. sativa tissues and also in response to abiotic elicitors. Each gene followed a different expression profile and expression level in target tissues. The expression of all studied genes were up-regulated by exogenous application of MJ and SA on N. sativa leaves (at 24 h after treatments), except of GDS which its transcript was not induced by SA. The higher expression of these genes in response to abiotic elicitors might reflect an elevation in the corresponding metabolites; hence elicitation is an applicable tool for enhancement of pharmaceutically active mono/triterpenes in N. sativa.

The genetic diversity of 39 Iranian black cumin (Nigella sativa L.) landraces was analysed using 14 polymorphic Start Codon Targeted (SCoT) markers. A total of 106 bands ranging from 3 (for SCoT70) to 13 (for SCoT23) were observed. Of them, 33 (31%) bands were polymorphic with a mean of 1.65 bands per primer. Polymorphism information content (PIC) per primer ranged from 0.035 (for SCoT12) to 0.133 (for SCoT70), with an average of 0.078. Besides PIC, Simpson's diversity (D) index was also calculated for each SCoT marker as an indication of discrimination power across population. The D index was used to adjust the PIC of the SCoT markers. As the adjusted PIC (PICD= PIC × D) was calculated based on both the PIC and the rate of band dispersion, this reflected the informativeness of a dominant marker more precisely than PIC. Genetic relationships were estimated using Jaccard's similarity coefficient-generated values between different pairs of genotypes that varied from 80 to 97% with an average of 88%. These coefficients were applied to construct a dendrogram using the UPGMA algorithm. A high genetic similarity was observed that might be due to the fact that N. sativa is a self-pollinated plant not originated from Iran and might have been imported from the Mediterranean regions.

Ideograms are diagrammatic or idealized representations of chromosomes, showing their relative size, homologous groups and cytogenetic landmarks. Chromosomal analysis of cytological preparations involves calculation of karyotypic parameters and generation of ideograms. We generated IdeoKar, a free and user-friendly karyotype analysis software that facilitates data collection from different digital images of metaphase chromosome spreads and calculates a wide variety of chromosomal and karyotypic parameters along with the related standard errors which can be saved as a Microsoft Excel file. This software is also capable of drawing ideograms of both diploid and allopolyploid species in a single image file. IdeoKar is designed to fast and efficient karyotype analysis and ideogram generation. It can be used with personal computers without any specific hardware. This software and related documentation is freely available at the website of the University of Kurdistan at: http://agri.uok.ac.ir/ideokar/index.html.

NOR loci of C-subgenome are dominant in wheat × Aegilops interspecific hybrids, which may have evolutionary implications for wheat group genome dynamics and evolution. After interspecific hybridisation, some genes are often expressed from only one of the progenitor species, shaping subsequent allopolyploid genome evolution processes. A well-known example is nucleolar dominance, i.e. the formation of cell nucleoli from chromosomes of only one parental species. We studied nucleolar organizing regions (NORs) in diploid Aegilops markgrafii (syn: Ae. caudata; CC), Ae. umbellulata (UU), allotetraploids Aegilops cylindrica (CcCcDcDc) and Ae. triuncialis (CtCtUtUt), synthetic interspecific F1 hybrids between these two allotetraploids and bread wheat (Triticum aestivum, AABBDD) and in F3 generation hybrids with genome composition AABBDDCtCtUtUt using silver staining and fluorescence in situ hybridization (FISH). In Ae. markgrafii (CC), NORs of both 1C and 5C or only 5C chromosome pairs were active in different individual cells, while only NORs on 1U chromosomes were active in Ae. umbellulata (UU). Although all 35S rDNA loci of the Ct subgenome (located on 1Ct and 5Ct) were active in Ae. triuncialis, only one pair (occupying either 1Cc or 5Cc) was active in Ae. cylindrica, depending on the genotype studied. These C-genome expression patterns were transmitted to the F1 and F3 generations. Wheat chromosome NOR activity was variable in Ae. triuncialis × T. aestivum F1 seeds, but silenced by the F3 generation. No effect of maternal or paternal cross direction was observed. These results indicate that C-subgenome NOR loci are dominant in wheat × Aegilops interspecific hybrids, which may have evolutionary implications for wheat group genome dynamics and allopolyploid evolution.

We evaluated the genome structure and salt stress response of BC1F6 lines derived from a cross between an Iranian salt tolerant bread wheat cultivar ‘Roushan’ (2n=6x=42, AABBDD) and a synthetic allohexaploid Tritipyrum (2n=6x=42, AABBEbEb). Sixteen lines (L1 to L16) and their parents were studied for their chromosome composition, K+ : Na+ ratio, and relative dry mass (RDM) by growing them in nutrient solution containing 0 (control) or 100 mM NaCl (treatment). Among the studied lines, eight wheatThinopyrum bessarabicum (Eb genome) disomic substitution lines were identified using PCR-based Landmark Unique Gene (PLUG) markers and cytogenetic analysis. Ten (37%) of 27 PLUG markers used were informative for Eb chromosomes 1, 2, 3, 4, and 6 in a wheat background. PLUG markers also revealed that one line, L9, was a disomic substitution line DS2Eb(2B), and that seven lines, L3, L4, L7, L8, L14, L15, and L16, were DS6Eb(6D). There were large differences in morphological traits and salinity tolerance even among DS6Eb(6D) substitutions or untranslocated lines, due perhaps to unidentified rearrangements or small introgressions.

Meiosis is an ancestral, highly conserved process in eukaryotic life cycles, and for all eukaryotes the shared component of sexual reproduction. The benefits and functions of meiosis, however, are still under discussion, especially considering the costs of meiotic sex. To get a novel view on this old problem, we filter out the most conserved elements of meiosis itself by reviewing the various modifications and alterations of modes of reproduction. Our rationale is that the indispensable steps of meiosis for viability of offspring would be maintained by strong selection, while dispensable steps would be variable. We review evolutionary origin and processes in normal meiosis, restitutional meiosis, polyploidization and the alterations of meiosis in forms of uniparental reproduction (apomixis, apomictic parthenogenesis, automixis, selfing) with a focus on plants and animals. This overview suggests that homologue pairing, double-strand break formation and homologous recombinational repair at prophase I are the least dispensable elements, and they are more likely optimized for repair of oxidative DNA damage rather than for recombination. Segregation, ploidy reduction and also a biparental genome contribution can be skipped for many generations. The evidence supports the theory that the primary function of meiosis is DNA restoration rather than recombination.

Development of wheat-alien translocation lines will facilitate its practical utilization in wheat improvement. The objective of the present study was to produce compensating wheat--Thinopyrum bessarabicum whole arm Robertsonian translocations (RobTs) involving chromosomes 2B of wheat and 2E(b) of Th. bessarabicum through the mechanism of centric breakage-fusion. F2 population from crosses between DS2E(b)(2B) substitution line and bread wheat 'Roushan' (2n = 6x = 42, AABBDD) as female parent were made. Forty one F2 lines (L1 to L41) were screened for their chromosome composition. Three 2E(b) specific PCR-based Landmark Unique Gene (PLUG) markers were used for screening F2 progeny derived from plants double-monosomic for chromosome 2B and 2E(b). Two Rob Ts (-5%) were observed among F2 plants. Homozygous translocation (T2E(b)S.2BL) with good plant vigor and full fertility were selected from F3 families. The T2E(b)S.2BL stock has longer awn than that of its parents. It is cytogenetically stable, and may be useful in wheat improvement.

The presence of homologous subgenomes inhibited unreduced gamete formation in wheat × Aegilops interspecific hybrids. Unreduced gamete rates were under the control of the wheat nuclear genome. Production of unreduced gametes is common among interspecific hybrids, and may be affected by parental genotypes and genomic similarity. In the present study, five cultivars of Triticum aestivum and two tetraploid Aegilops species (i.e. Ae. triuncialis and Ae. cylindrica) were reciprocally crossed to produce 20 interspecific hybrid combinations. These hybrids comprised two different types: T. aestivum × Aegilops triuncialis; 2n = ABDUtCt (which lack a common subgenome) and T. aestivum × Ae. cylindrica; 2n = ABDDcCc (which share a common subgenome). The frequency of unreduced gametes in F1 hybrids was estimated in sporads from the frequency of dyads, and the frequency of viable pollen, germinated pollen and seed set were recorded. Different meiotic abnormalities recorded in the hybrids included precocious chromosome migration to the poles at metaphase I and II, laggards in anaphase I and II, micronuclei and chromosome stickiness, failure in cell wall formation, premature cytokinesis and microspore fusion. The mean frequency of restitution meiosis was 10.1 %, and the mean frequency of unreduced viable pollen was 4.84 % in T. aestivum × Ae. triuncialis hybrids. By contrast, in T. aestivum × Ae. cylindrica hybrids no meiotic restitution was observed, and a low rate of viable gametes (0.3 %) was recorded. This study present evidence that high levels of homologous pairing between the D and Dc subgenomes may interfere with meiotic restitution and the formation of unreduced gametes. Variation in unreduced gamete production was also observed between T. aestivum × Ae. triuncialis hybrid plants, suggesting genetic control of this trait.

Isabgol is an annual herb cultivated as a medicinal plant. In the present study, karyotypic analysis of 12 Iranian endemic Isabgol (Plantago ovata Forsk.) ecotypes was carried out. The chromosome number was 2n=2x=8 with 4m+4st karyotype formula. The mean value of total chromosome length (TL) was 2.86 μm, ranging from 2.44 μm (E4) to 3.26 μm (E12). All ecotypes had 2 pairs of satellites (3S, 4S), varying in size from 0.34 to 0.36 μm. Most of the chromosomal parameters were significantly different among the various ecotypes. In general, karyotypes were symmetrical and fell in the Stebbins 2A category. The scatter diagram of A1 and A2 asymmetry indicated 4 groups of ecotypes while PCA analysis together with cluster analysis and scatter diagram of TL and CI, showed 3 groups, containing 9, 2 and 1 ecotypes, respectively. C-Banding patterns and fluorescence in situ hybridization (FISH) with 45S rDNA probe provided landmarks for chromosome identification in somatic preparations.

The new salt tolerant cereal, Tritipyrum (2n=6x=42, AABBEbEb) offers potential to introduce desirable characters for wheat improvements. This study was aimed to generate a segregating population from Iranian local wheat cultivars (2n=6x=42, AABBDD) and Tritipyrum crosses, study of the meiotic behaviour in F2 hybrids and identification of Eb chromosomes in F3 individuals. Results showed meiotic abnormalities in F2 plants and different pairing frequency in the meiosis among F2 plants. Genomic in situ hybridization revealed that total and Eb chromosome number of F3 seeds ranged from 39 to 45 and 0 to 10, respectively. A significant prevalence of hyper-aneuploidy was observed among F3 genotypes. C-banding patterns identified Eb chromosomes in Tritipyrum, indicating that it also can be useful to study wheat-Tritipyrum derivatives.

C-banded pattern in two accessions of Thinopyrum bessarabicum (Save ex Rayss) A. Love (2n = 2x = 14, EbEb) and their idiogram was established. C-banding analysis was further used to identify the chromosomes of Tritipyrum amphiploid (2n = 6x = 42, AABBEbEb) and a BC1F2 genotype from wheat and Tritipyrum. Two 18S-26S rDNA loci were detected on Th. bessarabicum chromosomes by in situ hybridization using an 18S-26S rDNA probe. Eb chromosomes in Tritipyrum generally were identified by their distinctive C-banding patterns which reflected heterochromatin regions. C-banding procedure resulted in sharp and distinct bands in one or both ends of Eb chromosomes without interval bands. Observed C-bands in Eb genome mainly reflected the telomeric and subtelomeric sequences which also showed more strong signals in genomic in situ hybridization. Results showed the importance of the C-banding technique as a screening tool in identification of addition and substitution lines in the progenies of wheat and Tritipyrum crosses during segregating generations.

Background Species belonging to the genus Aegilops L. are an important source of genetic material for expanding genetic variability of wheat. Ae. triuncialis is an allotetraploid in this genus which was originated from hybridization of Ae. umbellulata and Ae. markgrafii (Greuter) Hammer. Although the Ae. triuncialis karyotype was thoroughly examined by conventional chromosome staining and Giemsa C-banding, it is still poorly characterized using FISH markers. The objective of this study was to test the fluorescence in situ hybridization (FISH) patterns of Ae. triuncialis (2n = 4x = 28, CtCtUtUt) chromosomes using different repetitive sequences and to compare the produced patterns to the chromosomes of its diploid ancestors, with the aim of establishing a generalized Ae. triuncialis idiogram and detection of Aegilops chromosomes in the background of wheat. Results The probes pSc119.2-1, pTa535-1, pAs1-1, (CTT)10 and the 45S rDNA clone from wheat (pTa71) were hybridized to chromosomes of Ae. triuncialis and compared with its diploid progenitors (Ae. umbellulata Zhuk., 2n = 2x = 14, UU and Ae. markgrafii (Greuter) Hammer, 2n = 2x = 14, CC) and Ae. cylindrica Host. (2n = 4x = 28, DcDcCcCc), another tetraploid species containing the C-genome. Ae. cylindrica was further analyzed by genomic in situ hybridization (GISH) using C genome probe in order to identify any possible translocation. Conclusions In general, FISH patterns of the Ut- and Ct-genome chromosomes of Ae. triuncialis were similar to those of U- and C-genome chromosomes of the diploid progenitor species Ae. umbellulata and Ae. markgrafii respectively, although some differences were observed. Two major 45S rDNA loci were revealed in the short arm of chromosomes A and C, of the Ct genome which correspond to homoeologous groups 1 and 5 respectively. Minor 45S rDNA loci were mapped on the short arm of chromosomes 1Ut and 5Ut. GISH analysis revealed three different non-reciprocal homologous or heterologous translocations between Cc and Dc chromosomes in all studied accessions of Ae. cylindrica. Electronic supplementary material The online version of this article (doi:10.1186/s13039-014-0091-6) contains supplementary material, which is available to authorized users.

Lophopyrum elongatum (tall wheatgrass), a wild relative of wheat, can be used as a source of novel genes for improving salt tolerance of bread wheat. Sodium 'exclusion' is a major physiological mechanism for salt tolerance in a wheat-tall wheatgrass amphiploid, and a large proportion ( approximately 50%) for reduced Na(+) accumulation in the Xag leaf, as compared to wheat, was earlier shown to be contributed by genetic effects from substitution of chromosome 3E from tall wheatgrass for wheat chromosomes 3A and 3D. Homoeologous recombination between 3E and wheat chromosomes 3A and 3D was induced using the ph1b mutant, and putative recombinants were identified as having SSR markers specific for tall wheatgrass loci. As many as 14 recombinants with smaller segments of tall wheatgrass chromatin were identified and low-resolution breakpoint analysis was achieved using wheat SSR loci. Seven recombinants were identified to have leaf Na+ concentrations similar to those in 3E(3A) or 3E(3D) substitution lines, when grown in 200 mM NaCl in nutrient solution. Phenotypic analysis identified recombinants with introgressions at the distal end on the long arm of homoeologous group 3 chromosomes being responsible for Na(+) 'exclusion'. A total of 55 wheat SSR markers mapped to the long arm of homoeologous group 3 markers by genetic and deletion bin mapping were used for high resolution of wheat-tall wheatgrass chromosomal breakpoints in selected recombinants. Molecular marker analysis and genomic in situ hybridisation confirmed the 524-568 recombinant line as containing the smallest introgression of tall wheatgrass chromatin on the distal end of the long arm of wheat chromosome 3A and identified this line as suitable for developing wheat germplasm with Na(+) 'exclusion'.

Chromosome 1R of rye is a useful source of genes for disease resistance and enhanced agronomic performance in wheat. One of the most prevalent genes transferred to wheat from rye is the stem rust resistance gene Sr31. The recent emergence and spread of a stem rust pathotype virulent to this gene has refocused efforts to find and utilize alternative sources of resistance. There has been considerable effort to transfer a stem rust resistance gene, SrR, from Imperial rye, believed to be allelic to Sr31, into commercial wheat cultivars. However, the simultaneous transfer of genes at the Sec-1 locus encoding secalin seed storage proteins and their association with quality defects preclude the deployment of SrR in some commercial wheat breeding programs. Previous attempts to induce homoeologous recombination between wheat and rye chromosomes to break the linkage between SrR and Sec-1 whilst retaining the tightly linked major loci for wheat seed storage proteins, Gli-D1 and Glu-D3, and recover good dough quality characteristics, have been unsuccessful. We produced novel tertiary wheat–rye recombinant lines carrying different lengths of rye chromosome arm 1RS by inducing homoeologous recombination between the wheat 1D chromosome and a previously described secondary wheat–rye recombinant, DRA-1. Tertiary recombinant T6-1 (SrR+ Sec-1–) carries the target gene for stem rust resistance from rye and retains Gli-D1 but lacks the secalin locus. The tertiary recombinant T49-7 (SrR– Sec-1+) contains the secalin locus but lacks the stem rust resistance gene. T6-1 is expected to contribute to wheat breeding programs in Australia, whereas T49-7 provides opportunities to investigate whether the presence of secalins is responsible for the previously documented dough quality defects.

An efficient colchicine-mediated chromosome doubling of diploid feverfew followed by the morphophenological, physiological, phytochemical, and cytological changes of the obtained tetraploid plants was conducted. One-week-old seedlings of feverfew were treated with 0.05% (w/v) colchicine for 2, 4, 6, 8, and 24 h. Tetraploid plants were regenerated after 4 months, showing significant changes in stomatal size and density; sizes of seed; flower, pollen, leaf, trichome, cell, nucleus, and parthenolide content; chromosome number; ploidy level; chlorophyll content index; and quantum efficiency of photosystem II. Such characteristics of induced tetraploid feverfews can be useful in medicinal and ornamental applications, e.g., the study of flower morphogenesis, trichome differentiation, and parthenolide biosynthesis. The increase in parthenolide in tetraploids of the next generation (selfed T0 plants) showed that ploidy induction is a good breeding method for feverfew.