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Introduction: Emerging new races of leaf rust (Puccinia triticina Eriks) are threatening global wheat (Triticum aestivum L.) production. Identifying additional resistance genes from all available gene pools is crucial to expanding wheat resistance to these virulent leaf rust races. Siberian wild rye (Elymus sibiricus L.) possesses numerous beneficial traits that can be valuable in wheat improvement. Three new wheat- E. sibiricus addition lines, O27-2 (BC8), O27-3 (BC12) and O193-3 (BC12), were developed through a backcrossing scheme in this study, using leaf rust field evaluations, molecular marker assays and cytogenetic analysis. Methods: These three lines were derived from progeny of the bread wheat cultivar 'Obriy' (2 n = 6 x = 42, AABBDD) and partial octoploid amphiploid wheat- E. sibiricus (2 n = 8 x = 56, AABBDDStSt). Results and discussion: The lines (O27-2, O27-3 and O193-3) demonstrated strong specific leaf pubescence (hairiness) and resistance at the adult stage to a local population of leaf rust races. The response to leaf rust in these three lines significantly differed from that of the Lr24 gene, providing evidence for a distinct resistance mechanism associated with the 3St chromosome. This study is the first to report the transfer of an E. sibiricus chromosome into wheat that confers leaf rust resistance. Molecular marker analysis and genomic in situ hybridization confirmed that lines O27-2, O27-3 and O193-3 each possess one pair of E. sibiricus 3St chromosomes. The resistance gene was determined to be on the additional alien chromosome in these lines. Molecular markers (Xwmc221, Lr29F18, Sr24/Lr24) confirmed that the lines O27-2, O27-3, and O193-3 each contain a pair of E. sibiricus 3St chromosomes carrying leaf rust resistance genes. These findings demonstrate that the E. sibiricus 3St chromosome carries the leaf rust resistance gene and that the O27-2, O27-3, and O193-3 lines can serve as novel germplasm sources for introducing this resistance into wheat breeding programs. This study contributes to broadening the genetic diversity of resistance genes available for combating leaf rust in wheat. [ABSTRACT FROM AUTHOR]

IntroductionEmerging new races of leaf rust (Puccinia triticina Eriks) are threatening global wheat (Triticum aestivum L.) production. Identifying additional resistance genes from all available gene pools is crucial to expanding wheat resistance to these virulent leaf rust races. Siberian wild rye (Elymus sibiricus L.) possesses numerous beneficial traits that can be valuable in wheat improvement. Three new wheat-E. sibiricus addition lines, O27-2 (BC8), O27-3 (BC12) and O193-3 (BC12), were developed through a backcrossing scheme in this study, using leaf rust field evaluations, molecular marker assays and cytogenetic analysis. MethodsThese three lines were derived from progeny of the bread wheat cultivar ‘Obriy’ (2n = 6x = 42, AABBDD) and partial octoploid amphiploid wheat-E. sibiricus (2n = 8x = 56, AABBDDStSt). Results and discussionThe lines (O27-2, O27-3 and O193-3) demonstrated strong specific leaf pubescence (hairiness) and resistance at the adult stage to a local population of leaf rust races. The response to leaf rust in these three lines significantly differed from that of the Lr24 gene, providing evidence for a distinct resistance mechanism associated with the 3St chromosome. This study is the first to report the transfer of an E. sibiricus chromosome into wheat that confers leaf rust resistance. Molecular marker analysis and genomic in situ hybridization confirmed that lines O27-2, O27-3 and O193-3 each possess one pair of E. sibiricus 3St chromosomes. The resistance gene was determined to be on the additional alien chromosome in these lines. Molecular markers (Xwmc221, Lr29F18, Sr24/Lr24) confirmed that the lines O27-2, O27-3, and O193-3 each contain a pair of E. sibiricus 3St chromosomes carrying leaf rust resistance genes. These findings demonstrate that the E. sibiricus 3St chromosome carries the leaf rust resistance gene and that the O27-2, O27-3, and O193-3 lines can serve as novel germplasm sources for introducing this resistance into wheat breeding programs. This study contributes to broadening the genetic diversity of resistance genes available for combating leaf rust in wheat.

Background. Hordeum bulbosum L. is the only wild species of the genus Hordeum, the gene pool of which is successfully used in introgressive hybridization to increase the genetic diversity of H. vulgare L. When creating introgression forms based on hybrids of H. vulgare with H. bulbosum, it is necessary to take into consideration the ploidy of the parent species, and their genetic features that determine the intensity of the process of H. bulbosum chromosomes elimination in embryogenesis. The purpose of our investigation was to study the features associated with the elimination of bulbous barley chromosomes in embryos obtained in various combinations of crosses involving the tetraploid hybrid H. bulbosum with H. vulgare for its effective use in obtaining introgression lines of H. vulgare. Material and methods. The analysis was performed on 9-15 days old embryos obtained in crosses of the tetraploid hybrid F2 (H. bulbosum A17 (4x) × H. vulgare ‘Borwina’ (4x)) (HbHbHvHv) with ‘Igri’ (2x) and ‘Borwina’ (2x) barley varieties, with H. bulbosum A17 (4x), as well as during its self-pollination. The chromosomal composition of embryos of different ages was analyzed on squashed embryo slides using genomic in situ hybridization (GISH). Results. Among the 11-15 days old embryos obtained from self-pollination of the hybrid, approximately half of the studied ones were mixoploids, while in other embryos the majority of cells contained only the genomic material of H. vulgare. The elimination process was very intensive in crosses of the hybrid with the barley varieties ‘Igri’ (2x) and ‘Borwina’ (2x), and by day 10-11 after pollination cells containing only the genomic material of H. vulgare predominated in all embryos, regardless of the direction of crossing and the variety used. Hybrid embryos with a stable chromosomal composition resulted from a cross of a tetraploid hybrid with H. bulbosum A17 (4x). Embryos with recombinant H. vulgare chromosomes carrying alien genetic material of bulbous barley were identified in all types of crosses. Conclusion. The most efficient way for the mass production of introgression lines of cultivated barley varieties based on the partially fertile hybrid F2 (H. bulbosum A17 (4x) × H. vulgare ‘Borwina’ (4x)), is the crossing with varieties of H. vulgare (2x). The progeny from such crosses will contain only cultivated barley plants, among which it is possible to identify forms with the introgression of H. bulbosum and use already the first generation from their self-pollination for selecting H. vulgare lines carrying the genetic material of bulbous barley in both homologs.

Wheat, including durum and common wheat, respectively, is an allopolyploid with two or three homoeologous subgenomes originating from diploid wild ancestral species. The wheat genome's polyploid origin consisting of just three diploid ancestors has constrained its genetic variation, which has bottlenecked improvement. However, wheat has a large number of relatives, including cultivated crop species (e.g., barley and rye), wild grass species, and ancestral species. Moreover, each ancestor and relative has many other related subspecies that have evolved to inhabit specific geographic areas. Cumulatively, they represent an invaluable source of genetic diversity and variation available to enrich and diversify the wheat genome. The ancestral species share one or more homologous genomes with wheat, which can be utilized in breeding efforts through typical meiotic homologous recombination. Additionally, genome introgressions of distant relatives can be moved into wheat using chromosome engineering-based approaches that feature induced meiotic homoeologous recombination. Recent advances in genomics have dramatically improved the efficacy and throughput of chromosome engineering for alien introgressions, which has served to boost the genetic potential of the wheat genome in breeding efforts. Here, we report research strategies and progress made using alien introgressions toward the enrichment and diversification of the wheat genome in the genomics era. [ABSTRACT FROM AUTHOR]

Cotton (Gossypium species) has received considerable interest from the geneticists, cytologists and evolutionary biologists since the last more than a century. Here, we explore the genetics of petal spot in the interspecific derivatives involving tetraploid and diploid cottons; and confirm the location of gene governing petal spot phenotype on chromosome A7 by demonstrating co-segregation of SSR marker NAU 2186 with petal spot phenotype. The presence of petal spot was observed to be dominant over its absence. Petal spot inheritance showed significant deviation from the expected Mendelian ratio in all the segregating populations indicating segregation distortion. The distortion was biased towards the hirsutum parent which has important implications from introgression point of view. We also report a strong association between petal spot and petal margin coloration phenotypes. Extant American cotton varieties generally lack petal spot and margin coloration phenotypes. These petal characteristics can serve as morphological markers during germplasm characterization.

This study characterized six introgression lines obtained from crossing two winter bread wheat varieties Albena and Slaveya with the D-genome synthetic hexaploid wheat 530-1. Phenotypically, the lines differed from the parents, as five of them expressed red spike color versus line 45-5 producing new coloration, identified as striped or banded glume pigmentation. All lines were taller, with longer ears and spikelets, later in heading time and less productive in grain yield than both wheat parents. They showed some positive traits in the field: optimal test weight (78–80 kg/hl), high thousand kernel weight (48–51 g), low sprouted seeds (0.3–1.5%), and high falling number (314-350 s). Two lines (38-7 and 46-7) exceeded the parents in grain protein content. In the competitive variety trial, Albena showed significantly higher sprouted grains (4.1%) and extreme measurements for a percentage of germination (99.0%) and germination index (83.0%) in 2022. The data identified Albena as a wheat variety with pre-harvest sprouting susceptibility. Of the lines, only 45-5 stood out with the lowest germination values and appeared as a promising genotype with resistance to pre-harvest sprouting. The introgression lines exerted useful genetic diversity for the studied traits and could serve as resources for quality improvement in wheat breeding programs.

This study characterized six introgression lines obtained from crossing two winter bread wheat varieties Albena and Slaveya with the D-genome synthetic hexaploid wheat 530-1. Phenotypically, the lines differed from the parents, as five of them expressed red spike color versus line 45-5 producing new coloration, identified as striped or banded glume pigmentation. All lines were taller, with longer ears and spikelets, later in heading time and less productive in grain yield than both wheat parents. They showed some positive traits in the field: optimal test weight (78-80 kg/hl), high thousand kernel weight (48-51 g), low sprouted seeds (0.3-1.5%), and high falling number (314-350 s). Two lines (38-7 and 46-7) exceeded the parents in grain protein content. In the competitive variety trial, Albena showed significantly higher sprouted grains (4.1%) and extreme measurements for a percentage of germination (99.0%) and germination index (83.0%) in 2022. The data identified Albena as a wheat variety with pre-harvest sprouting susceptibility. Of the lines, only 45-5 stood out with the lowest germination values and appeared as a promising genotype with resistance to pre-harvest sprouting. The introgression lines exerted useful genetic diversity for the studied traits and could serve as resources for quality improvement in wheat breeding programs. [ABSTRACT FROM AUTHOR]

Among the cereal crops, wheat is an important food crop and acts as the staple food for more than half of the world's population. The genetic bottleneck of domestication and modernization has narrowed down the genetic base for different economically important traits in wheat. The involvement of wild species in the wheat hybridization program faced the difficulties of pre- and post-fertilization barriers and the presence of Ph1 locus. The distant crosses provide useful variation which is beneficial for wheat improvement programs. The wild relative species of wheat harbor several important genes for nutritional traits such as gluten protein, micronutrients (grain Fe and Zn), vitamins, and other minerals and play a significant role in end-use quality. The gluten strength relies upon the glutenin protein. The glutenin consists of two types, i.e., high molecular weight glutenins (HMW-GS) and low molecular weight glutenins (LMW-GS) which help in improving wheat processing quality. In wheat, gene transfer occurs as a consequence of direct cross, breeding protocols, and genetic recombination assisted by special manipulation techniques. Alien introgression from wild relatives is an important source of new allelic variation for the genetic enhancement of nutritional quality. The wild relative species such as Aegilops spp., T. boeoticum, and T. dicoccoides have been used in hybridization, and genes related to protein, and micronutrients have been transferred in the cultivated varieties. Through this review, an attempt has been made to compile comprehensive information on the potential of wild species for the improvement of nutritional and end-use quality traits through alien introgression. [ABSTRACT FROM AUTHOR]

The Thinopyrum elongatum Fhb7E locus has been proven to confer outstanding resistance to Fusarium Head Blight (FHB) when transferred into wheat, minimizing yield loss and mycotoxin accumulation in grains. Despite their biological relevance and breeding implications, the molecular mechanisms underlying the resistant phenotype associated with Fhb7E have not been fully uncovered. To gain a broader understanding of processes involved in this complex plant–pathogen interaction, we analysed via untargeted metabolomics durum wheat (DW) rachises and grains upon spike inoculation with Fusarium graminearum (Fg) and water. The employment of DW near-isogenic recombinant lines carrying or lacking the Th. elongatum chromosome 7E region including Fhb7E on their 7AL arm, allowed clear-cut distinction between differentially accumulated disease-related metabolites. Besides confirming the rachis as key site of the main metabolic shift in plant response to FHB, and the upregulation of defence pathways (aromatic amino acid, phenylpropanoid, terpenoid) leading to antioxidants and lignin accumulation, novel insights were revealed. Fhb7E conferred constitutive and early-induced defence response, in which specific importance of polyamine biosynthesis, glutathione and vitamin B6 metabolisms, along with presence of multiple routes for deoxynivalenol detoxification, was highlighted. The results suggested Fhb7E to correspond to a compound locus, triggering a multi-faceted plant response to Fg, effectively limiting Fg growth and mycotoxin production. [ABSTRACT FROM AUTHOR]

Abstract Background The tall wheatgrass species Thinopyrum elongatum carries a strong fusarium head blight (FHB) resistance locus located on the long arm of chromosome 7 (7EL) as well as resistance to leaf and stem rusts, all diseases with a significant impact on wheat production. Towards understanding the contribution of Th. elongatum 7EL to improvement of disease resistance in wheat, the genomic sequence of the 7EL fragment present in the wheat Chinese Spring (CS) telosomic addition line CS-7EL was determined and the contribution and impact of 7EL on the rachis transcriptome during FHB infection was compared between CS and CS-7EL. Results We assembled the Th. elongatum 7EL chromosome arm using a reference-guided approach. Combining this assembly with the available reference sequence for CS hexaploid wheat provided a reliable reference for interrogating the transcriptomic differences in response to infection conferred by the 7EL fragment. Comparison of the transcriptomes of rachis tissues from CS and CS-7EL showed expression of Th. elongatum transcripts as well as modulation of wheat transcript expression profiles in the CS-7EL line. Expression profiles at 4 days after infection with Fusarium graminearum, the causal agent of FHB, showed an increased in expression of genes associated with an effective defense response, in particular glucan endo-1,3-beta-glucosidases and chitinases, in the FHB-resistant line CS-7EL while there was a larger increase in differential expression for genes associated with the level of fungal infection in the FHB-susceptible line CS. One hundred and seven 7EL transcripts were expressed in the smallest 7EL region defined to carry FHB resistance. Conclusion 7EL contributed to CS-7EL transcriptome by direct expression and through alteration of wheat transcript profiles. FHB resistance in CS-7EL was associated with transcriptome changes suggesting a more effective defense response. A list of candidate genes for the FHB resistance locus on 7EL has been established.

Background. The use of alien genetic material of bulbous barley Hordeum bulbosum L. to increase the diversity of cultivated barley Hordeum vulgare L. is an important task, since H. bulbosum is characterized by a number of valuable traits. One of the ways to use the genetic potential of bulbous barley is the interspecific hybridization and obtaining fertile introgressive lines of H. vulgare based on interspecific hybrids. The aim of the study was to obtain new introgressive forms of spring barley using interspecific triploid (HvHbHb) and tetraploid (HbHbHvHv) hybrids of cultivated barley with bulbous barley to expand the collection of introgressive lines of H. vulgare. Materials and methods. To create new introgressive forms, diploid barley H. vulgare (2x) cv. ‘Roland’, was crossed with interspecific hybrids H. vulgare cv. ‘Roland’(2x) × H. bulbosum W851 (4х) (HvHbHb), and H. bulbosum A17 (4x) × H. vulgare ‘Borwina’ (4x) (HbHbHvHv). Cultivated barley forms with introgression of the bulbous barley genetic material were selected from the offspring from these crosses; then the selection was continued in two progenies from self-pollination of selected BC1 plants with three alien introgressions. Identification and localization of introgressions was carried out using the method of fluorescent in situ hybridization (GISH and FISH with chromosome-specific markers). Results. The crossing of cultivated barley with triploid and tetraploid interspecific hybrids H. vulgare × H. bulbosum yielded new forms of cultivated barley with recombinant chromosomes, among which two plants with three terminal introgressions of the genetic material of bulbous barley were identified. The first plant, derived from a triploid hybrid, showed introgressions in chromosomes 5HL, 1HL and 3HS. When two homologues with the 5HL introgression of the initial size are combined in the karyotype, the lethality of seedlings is observed in the offspring plants. In the second plant obtained on the basis of a tetraploid hybrid introgression was revealed in chromosomes 5HL, 2HL, and 7HS. In the offspring from self-pollination of this form, the presence of the 2HL introgression of the original size in both homologues led to plant sterility. Forms with a change in size of the introgression in 5HL and 3HS in the offspring of the first plant and with a change in size of the introgression in 2HL in the offspring of the second plant were detected, which indicated that meiotic recombination had occurred in those chromosome regions in BC1 plants. Conclusions A barley plant with the introgression of bulbous barley chromatin into chromosomes 1HL, 5HL, and 3HS of cultivated barley was identified in the offspring from a cross of cultivated barley with a triploid interspecific hybrid H. vulgare × H. bulbosum. In crosses with a tetraploid interspecific hybrid, a barley plant with the introgression into chromosomes 2HL, 5HL, and 7HS was found. On the basis of ‘Roland’ spring barley cultivar, two series of new introgressive forms of H. vulgare with various combinations of recombinant chromosomes have been created.

Wheatgrass Thinopyrum intermedium is a source of agronomically valuable traits for common wheat. Partial wheat–wheatgrass amphidiploids and lines with wheatgrass chromosome substitutions are extensively used as intermediates in breeding programs. Line Agis 1 (6Agi2/6D) is present in the cultivar Tulaykovskaya 10 pedigree. Wheatgrass chromosome 6Agi2 carries multiple resistance to fungal diseases in various ecogeographical zones. In this work, we studied the transfer of chromosome 6Agi2 in hybrid populations Saratovskaya 29×Tulaykovskaya 10 (S29×T10) and Tulaykovskaya 10×Saratovskaya 29 (T10×S29). Chromosome 6Agi2 was identified by PCR with chromosome-specific primers and by genomic in situ hybridization (GISH). According to molecular data, 6Agi2 was transmitted to nearly half of the plants tested in the F2 and F3 generations. A new breeding line 49-14 (2n = 42) with chromosome pair 6Agi2 was isolated and characterized in T10×S29 F5 by GISH. According to the results of our field experiment in 2020, the line had high productivity traits. The grain weights per plant (10.04±0.93 g) and the number of grains per plant (259.36±22.49) did not differ significantly from the parent varieties. The number of grains per spikelet in the main spike was significantly higher than in S29 (p ≤ 0.001) or T10 (p ≤ 0.05). Plants were characterized by the ability to set 3.77±0.1 grains per spikelet, and this trait varied among individuals from 2.93 to 4.62. The grain protein content was 17.91 %, and the gluten content, 40.55 %. According to the screening for fungal disease resistance carried out in the field in 2018 and 2020, chromosome 6Agi2 makes plants retain immunity to the West Siberian population of brown rust and to dominant races of stem rust. It also provides medium resistant and medium susceptible types of response to yellow rust. The possibility of using lines/varieties of bread wheat with wheatgrass chromosomes 6Agi2 in breeding in order to increase protein content in the grain, to confer resistance to leaf diseases on plants and to create multiflowered forms is discussed.

The wide spread cultivation of transgenic Bt-cotton in India has altered the pest profile from bollworms to sap-sucking insect-pests especially whitefly [Bemisia tabaci (Gennadius)]. A whitefly epidemic in 2015 destroyed cotton crop on nearly 1.5 million hectares in North Indian cotton growing states. Management of whitefly is not easy due to its wider host adaptability, potential for insecticide resistance development and rapid evolution. Host plant resistance is the most viable approach for combating whitefly menace. A wild cotton species Gossypium armourianum Kearney Accession PAU 1 tolerant to various biotic stresses was used for the introgression of whitefly tolerance in Upland cotton (Gossypium hirsutum L.). Various morpho-anatomical characteristics (viz. stomatal frequency, gossypol glands, trichome density, leaf thickness) were studied from leaf discs in experimental material (i.e. parents G. armourianum Acc. PAU 1, G. hirsutum cv. F 1861 and LH 1556, F1, BC1F1, BC2F1 derivatives). The BC2F1 individuals differed significantly in stomatal frequency, trichome density, number of gossypol glands and lamina thickness; and hence their response to whitefly tolerance. However, with age progression, a significant decline in stomatal frequency, gossypol glands and trichome density were observed in mature leaves. Correlation studies revealed a positive association of whitefly incidence with trichome density (r = 0.319*) and stomatal frequency (r = 0.372*) in young leaves. A positive correlation of stomatal frequency with gossypol gland (ry = 0.251* and rm = 0.296*) and trichome density (ry = 0.360* and rm = 0.305*) was observed in both young and mature leaves. G. armourianum possessed 4–5 -folds higher tannin contents than G. hirsutum parents before infestation. Surprisingly in G. armourianum, increase in tannin levels were observed much earlier (after 24 h of infestation) as compared to G. hirsutum. [ABSTRACT FROM AUTHOR]

Background: The tall wheatgrass species Thinopyrum elongatum carries a strong fusarium head blight (FHB) resistance locus located on the long arm of chromosome 7 (7EL) as well as resistance to leaf and stem rusts, all diseases with a significant impact on wheat production. Towards understanding the contribution of Th. elongatum 7EL to improvement of disease resistance in wheat, the genomic sequence of the 7EL fragment present in the wheat Chinese Spring (CS) telosomic addition line CS-7EL was determined and the contribution and impact of 7EL on the rachis transcriptome during FHB infection was compared between CS and CS-7EL. Results: We assembled the Th. elongatum 7EL chromosome arm using a reference-guided approach. Combining this assembly with the available reference sequence for CS hexaploid wheat provided a reliable reference for interrogating the transcriptomic differences in response to infection conferred by the 7EL fragment. Comparison of the transcriptomes of rachis tissues from CS and CS-7EL showed expression of Th. elongatum transcripts as well as modulation of wheat transcript expression profiles in the CS-7EL line. Expression profiles at 4 days after infection with Fusarium graminearum, the causal agent of FHB, showed an increased in expression of genes associated with an effective defense response, in particular glucan endo-1,3-beta-glucosidases and chitinases, in the FHB-resistant line CS-7EL while there was a larger increase in differential expression for genes associated with the level of fungal infection in the FHB-susceptible line CS. One hundred and seven 7EL transcripts were expressed in the smallest 7EL region defined to carry FHB resistance. Conclusion: 7EL contributed to CS-7EL transcriptome by direct expression and through alteration of wheat transcript profiles. FHB resistance in CS-7EL was associated with transcriptome changes suggesting a more effective defense response. A list of candidate genes for the FHB resistance locus on 7EL has been established. [ABSTRACT FROM AUTHOR]

Background. One of the ways to use the genetic potential of bulbous barley, which is characterized by a number of valuable traits, is interspecific hybridization. In crosses of H. vulgare (2x) × H. bulbosum (2x) and H. vulgare (4x) × H. bulbosum (4x) with a genome ratio of 1Hv: 1Hb in a hybrid embryo, elimination of bulbous barley chromosomes is observed in many cases, and the intensity of the process and the result of the crossing depend on the genotypes of the parental forms. This limits the possibility of including a significant variety of parental forms in crosses. Сrossing of diploid forms of H. vulgare with tetraploid accessions of H. bulbosum (4x) results in the formation of triploid hybrids (HvHbHb) with stable chromosomal composition in pollen mother cells (PMCs) at metaphase I (MI) of meiosis. These triploid hybrids can serve as a basis for obtaining series of introgressive lines of cultivated barley. One of the tasks of this type of work is to estimate the involvement of various chromosomes and their arms in homoeologous associations. The aim of this work was to study the possibility of homoeologous pairing of chromosomes of parental species at MI of meiosis in triploid hybrids using GISH and FISH with chromosome-specific markers, as well as to register the participation of individual arms of the cultivated barley chromosomes in homoeologous associations with the chromosomes of bulbous barley in triploid hybrids (HvHbHb).Materials and methods. Seven triploid hybrids of H. vulgare × H.bulbosum (HvHbHb) obtained in four combinations of crosses with the participation of three diploid cultivars of cultivated barley and two tetraploid accession of bulbous barley were used in this study. The features of homoeologous pairing of chromosomes at MI were studied using the method of fluorescent in situ hybridization (GISH and FISH) with chromosome-specific markers.Results All the studied hybrid plants are characterized by a stable chromosomal composition in PMCs at the MI stage of meiosis. Meiotic configurations formed by homoeologous chromosomes of the parental species, ranging from 0.87 to 1.40 on average per cell, were identified in all the studied plants. Among them, vbb trivalents prevailed. Analysis of chromosome pairing at MI in triploid hybrids revealed the participation of all chromosome arms of H. vulgare in homoeologous Hv-Hb associations, except for the short arm of chromosome 1H. In all the studied triploid hybrids, there is a tendency for a higher frequency of involvement of the long arms of chromosomes in the formation of homoeologous associations; this feature is most clearly manifested in case of chromosome 5H.Conclusions Intergenomic associations with the participation of all arms of H. vulgare chromosomes, except for the short arm of chromosome 1H, were revealed at MI in H. vulgare × H. bulbosum triploid hybrids (HvHbHb). Chromosome 5H, as well as any other cultivated barley chromosome, is characterized by a higher involvement of its long arm in homoeologous associations Hv-Hb, as compared to the short arm.

Boron (B) is an important micronutrient required for the normal growth and development of plants. However, its excess in the soil causes severe damage to plant tissues, which affects the final yield. Wheat, one of the main staple crops, has been reported to be largely affected by B toxicity stress in arid and semi-arid regions of the world. The prevalence of B toxicity stress can be addressed by utilizing wild wheat genotypes with a variant level of stress tolerance. Wild wheat relatives have been identified as a prominent source of several abiotic stress-tolerant genes. However, Aegilops species in the tertiary gene pool of wheat have not been well exploited as a source of B toxicity tolerance. This study explores the root and shoot growth, proline induction, and extent of lipid peroxidation in 19 Aegilops accessions comprising 6 different species and the B-tolerant check wheat cultivar Bolal 2973 grown under Control (3.1 μM B), toxic (1 mM B), and highly toxic (10 mM B) B stress treatment. B toxicity stress had a more decisive impact on growth parameters as compared to the malondialdehyde (MDA) and proline content. The obtained results suggested that even the genotypes with high shoot B (SB) accumulation can be tolerant to B toxicity stress, and the mechanism of B redistribution in leaves should be studied in detail. It has been proposed that the studied Aegilops accessions can be potentially used for genetically improving the B toxicity-tolerance trait due to a high level of variation in the response toward high B toxicity. Though a number of accessions showed suppression in the root and shoot growth, very few accessions with stress adaptive plasticity to B toxicity stress leading to an improvement of shoot growth parameters could be determined. The two accessions, Aegilops biuncialis accession TGB 026219 and Aegilops columnaris accession TGB 000107, were identified as the potential genotypes with B toxicity stress tolerance and can be utilized for developing a pre-breeding material in B tolerance-based breeding programs.

Boron (B) is an important micronutrient required for the normal growth and development of plants. However, its excess in the soil causes severe damage to plant tissues, which affects the final yield. Wheat, one of the main staple crops, has been reported to be largely affected by B toxicity stress in arid and semi-arid regions of the world. The prevalence of B toxicity stress can be addressed by utilizing wild wheat genotypes with a variant level of stress tolerance. Wild wheat relatives have been identified as a prominent source of several abiotic stress-tolerant genes. However, Aegilops species in the tertiary gene pool of wheat have not been well exploited as a source of B toxicity tolerance. This study explores the root and shoot growth, proline induction, and extent of lipid peroxidation in 19 Aegilops accessions comprising 6 different species and the B-tolerant check wheat cultivar Bolal 2973 grown under Control (3.1 μM B), toxic (1 mM B), and highly toxic (10 mM B) B stress treatment. B toxicity stress had a more decisive impact on growth parameters as compared to the malondialdehyde (MDA) and proline content. The obtained results suggested that even the genotypes with high shoot B (SB) accumulation can be tolerant to B toxicity stress, and the mechanism of B redistribution in leaves should be studied in detail. It has been proposed that the studied Aegilops accessions can be potentially used for genetically improving the B toxicity-tolerance trait due to a high level of variation in the response toward high B toxicity. Though a number of accessions showed suppression in the root and shoot growth, very few accessions with stress adaptive plasticity to B toxicity stress leading to an improvement of shoot growth parameters could be determined. The two accessions, Aegilops biuncialis accession TGB 026219 and Aegilops columnaris accession TGB 000107, were identified as the potential genotypes with B toxicity stress tolerance and can be utilized for developing a pre-breeding material in B tolerance-based breeding programs. [ABSTRACT FROM AUTHOR]

The development of bread wheat introgressions with alien genetic material from cultural and wild Triticeae species is an effective method for expanding the wheat gene pool necessary for breeding. To date, numerous collections of introgressions as substitutions and chromosome modifications have been obtained; however, the creation and study of wheat with new valuable traits still remain an important line of research. Rye Secale cereale L., whose chromosomes carry genes that control valuable economic and biological characteristics and properties, is widely used to produce new wheat forms. In this study, a wheat-rye translocation obtained by backcrossing the wheat-rye disomic-substitution line 2R(2D)1 with the variety Novosibirskaya 67 was characterized. The chromosomal composition of karyotypes was studied using fluorescent in situ hybridization and C-banding. Two centric translocations, derived from two long arms of chromosomes 2D and 2R, T2DL.2RL, were identified, the remaining 40 wheat chromosomes did not undergo modifications. Meiosis in the lines was stable. Chromosomes T2DL.2RL formed bivalents in all meiocytes, which confirmed their homology. The morphological characteristics of the spike in the T2DL.2RL line and Novosibirskaya 67 did not differ. A comparative analysis of productivity between the T2DL.2RL translocation line and the parental forms, Novosibirskaya 67 and the 2R(2D)1 line, was carried out. The T2DL.2RL line is inferior to Novosibirskaya 67 in all characters with different confidence levels. The productivity characters of the 2R(2D)1 line exceeded or did not differ from those of T2DL.2RL, however, the mass of 1000 grains was significantly lower. The results showed the effect of the T2DL.2RL translocation on the trait “plant height”. This character was significantly lower than that of Novosibirskaya 67 in two vegetation periods. Consequently, the T2DL.2RL translocation reduces plant height and productivity.

Background. Involving alien genetic material Hordeum bulbosum in the genome for the expansion of the genetic diversity of barley is a cultural important task because this species is characterized by a number of valuable traits. One way of using the genetic potential of bulbous barley is interspecies hybridization and the production of fertile introgressive lines of H. vulgare on the base of interspecies hybrids. The purpose of our investigation was to study introgressive lines of cultural barley obtained on the basis of the triploid hybrid H.vulgare cv 'Igri' (2x) × H. bulbosum (4x) in compare to the original Igri variety in the field conditions.Materials and methods. In the field conditions the barley lines with intro-gressions of the genetic material of bulbous barley in the different arms of chromosomes H. vulgare (1HL, 2HL, 3HL, 5HL, 7HL, 2HS, 1HL + 5HL) were studied. Methods. In situ hybridization (FISH, GISH) was used to identify the introgressions and to analyze their saving in line karyotypes after field reproduction. For cultivated in field conditions plants the estimation of winter survival and graininess were estimated. Structural analysis of plants was carried out on tillers of the main spike after maturation. The quality of the grain was determined by the non-destructive method of monitoring - near infrared spectroscopy, using the Infralum FT-10 BIC analyzer.Results. Closed flowering and self-pollination were observed for plants of the studied lines same as for parent variety. The introgressions were saved in the offspring when the plants cultivated in a field conditions without isolation of spike. The analysis showed that small fragments of chromosomes of H. bulbosum in chromosomes 1HL, 2HL, 3HL, 5HL,7HL, 1HL + 5HL of the studied lines do not significantly affect on characteristics (of fertility, productivity and grain quality) of the variety. Differences from the initial variety were observed at line 14.10 with the introgression of genetic material in the chromosome 2HS. It is characterized by lower fertility and productivity, and protein content in the grain is higher than that of the original variety.Conclusions. The studied lines are highfertile forms of barley. The introgression of the genetic material of H. bulbosum into the terminal region of the short arm of the chromosome 2H causes changes in some characteristics of the Igri variety.

Breeding progress in most crops has relied heavily on the exploitation of variation within the species’ primary gene pool, a process which is destined to fail once the supply of novel variants has been exhausted. Accessing a crop’s secondary gene pool, as represented by its wild relatives, has the potential to greatly expand the supply of usable genetic variation. The crop in which this approach has been most strongly championed is bread wheat (Triticum aestivum), a species which is particularly tolerant of the introduction of chromosomal segments of exotic origin thanks to the genetic buffering afforded by its polyploid status. While the process of introgression can be in itself cumbersome, a larger problem is that linkage drag and/or imperfect complementation frequently impose a yield and/or quality penalty, which explains the reluctance of breeders to introduce such materials into their breeding populations. Thanks to the development of novel strategies to induce introgression and of genomic tools to facilitate the selection of desirable genotypes, introgression breeding is returning as a mainstream activity, at least in wheat. Accessing variation present in progenitor species has even been able to drive genetic advance in grain yield. The current resurgence of interest in introgression breeding can be expected to result in an increased deployment of exotic genes in commercial wheat cultivars.

Editorial: Aegilops: Promising Genesources to Improve Agronomical and Quality Traits of Wheat Keywords: Aegilops sp.; stress tolerance; quality traits; genome analysis; alien introgression EN Aegilops sp. stress tolerance quality traits genome analysis alien introgression 1 4 4 07/20/20 20200714 NES 200714 Introduction of Aegilops I Aegilops i species have contributed significantly to wheat improvement despite the challenges in exploiting wild species, such as crossability and incompatibility ([2]; [7]). The 5S rDNA locus of chromosome 1S was probably lost in ancient I A. speltoides i prior to formation of cultivated I Triticum timopheevi i (AAGG genomes), but after the emergence of ancient emmer (AABB genomes). I A. tauschii i (2n = 2x = 14, genome DD), also known as Tausch's goatgrass, is the D genome donor of hexaploid bread wheat ( I T. aestivum i , 2n = 2x = 42, AABBDD genome). [Extracted from the article]

The study aimed at introgression of productivity enhancing traits and resistance to pod borer and Phytophthora stem blight from wild to cultivated pigeonpea through an inter-specific cross between Cajanus scarabaeoides (ICP 15683) and C. cajan (ICPL 20329). Progenies derived from the direct segregating (without backcross) population and backcross population were evaluated for yield and yield contributing traits namely fruiting branches and pods plant−1 and 100-seed weight. Introgressed progenies having higher fruiting branches, pods and yield plant−1 compared to the cultivated parent were identified in both populations. A few progenies with significantly shorter plant height, early flowering and early maturity as compared to both cultivated and wild parents were also recovered in both populations. Progenies from both the populations were identified with higher resistance to pod borer and Phytophthora stem blight. However, some introgressed progenies having lower seed weight and seeds per pod were also recovered. The promising progenies are currently being used in the breeding programme to develop cultivars with improved productivity and resistance to pod borer and Phytophthora stem blight. [ABSTRACT FROM AUTHOR]

Breeding progress in most crops has relied heavily on the exploitation of variation within the species' primary gene pool, a process which is destined to fail once the supply of novel variants has been exhausted. Accessing a crop's secondary gene pool, as represented by its wild relatives, has the potential to greatly expand the supply of usable genetic variation. The crop in which this approach has been most strongly championed is bread wheat (Triticum aestivum), a species which is particularly tolerant of the introduction of chromosomal segments of exotic origin thanks to the genetic buffering afforded by its polyploid status. While the process of introgression can be in itself cumbersome, a larger problem is that linkage drag and/or imperfect complementation frequently impose a yield and/or quality penalty, which explains the reluctance of breeders to introduce such materials into their breeding populations. Thanks to the development of novel strategies to induce introgression and of genomic tools to facilitate the selection of desirable genotypes, introgression breeding is returning as a mainstream activity, at least in wheat. Accessing variation present in progenitor species has even been able to drive genetic advance in grain yield. The current resurgence of interest in introgression breeding can be expected to result in an increased deployment of exotic genes in commercial wheat cultivars. [ABSTRACT FROM AUTHOR]

A set of 96 Brassica juncea–Erucastrum cardaminoides introgression lines (ILs) were developed with genomic regions associated with Sclerotinia stem rot (Sclerotinia sclerotiorum) resistance from a wild Brassicaceous species E. cardaminoides. ILs were assessed for their resistance responses to stem inoculation with S. sclerotiorum, over three crop seasons (season I, 2011/2012; II, 2014/2015; III, 2016–2017). Initially, ILs were genotyped with transferable SSR markers and subsequently through genotyping by sequencing. SSR based association mapping identified six marker loci associated to resistance in both A and B genomes. Subsequent genome-wide association analysis (GWAS) of 84 ILs recognized a large number of SNPs associated to resistance, in chromosomes A03, A06, and B03. Chromosomes A03 and A06 harbored the maximum number of resistance related SNPs. Annotation of linked genomic regions highlighted an array of resistance mechanisms in terms of signal transduction pathways, hypersensitive responses and production of anti-fungal proteins and metabolites. Of major importance was the clustering of SNPs, encoding multiple resistance genes on small regions spanning approximately 885 kb region on chromosome A03 and 74 kb on B03. Five SNPs on chromosome A03 (6,390,210-381) were associated with LRR-RLK (receptor like kinases) genes that encode LRR-protein kinase family proteins. Genetic factors associated with pathogen-associated molecular patterns (PAMPs) and effector-triggered immunity (ETI) were predicted on chromosome A03, exhibiting 11 SNPs (6,274,763-994). These belonged to three R-Genes encoding TIR-NBS-LRR proteins. Marker trait associations (MTAs) identified will facilitate marker assisted introgression of these critical resistances, into new cultivars of B. juncea initially and, subsequently, into other crop Brassica species.

A set of 96 Brassica juncea – Erucastrum cardaminoides introgression lines (ILs) were developed with genomic regions associated with Sclerotinia stem rot (Sclerotinia sclerotiorum) resistance from a wild Brassicaceous species E. cardaminoides. ILs were assessed for their resistance responses to stem inoculation with S. sclerotiorum , over three crop seasons (season I, 2011/2012; II, 2014/2015; III, 2016–2017). Initially, ILs were genotyped with transferable SSR markers and subsequently through genotyping by sequencing. SSR based association mapping identified six marker loci associated to resistance in both A and B genomes. Subsequent genome-wide association analysis (GWAS) of 84 ILs recognized a large number of SNPs associated to resistance, in chromosomes A03, A06, and B03. Chromosomes A03 and A06 harbored the maximum number of resistance related SNPs. Annotation of linked genomic regions highlighted an array of resistance mechanisms in terms of signal transduction pathways, hypersensitive responses and production of anti-fungal proteins and metabolites. Of major importance was the clustering of SNPs, encoding multiple resistance genes on small regions spanning approximately 885 kb region on chromosome A03 and 74 kb on B03. Five SNPs on chromosome A03 (6,390,210-381) were associated with LRR-RLK (receptor like kinases) genes that encode LRR-protein kinase family proteins. Genetic factors associated with pathogen-associated molecular patterns (PAMPs) and effector-triggered immunity (ETI) were predicted on chromosome A03, exhibiting 11 SNPs (6,274,763-994). These belonged to three R-Genes encoding TIR-NBS-LRR proteins. Marker trait associations (MTAs) identified will facilitate marker assisted introgression of these critical resistances, into new cultivars of B. juncea initially and, subsequently, into other crop Brassica species. [ABSTRACT FROM AUTHOR]

Today wheat cultivation is facing rapidly changing climate scenarios and yield instability, aggravated by the spreading of severe diseases such as Fusarium head blight (FHB) and Fusarium crown rot (FCR). To obtain productive genotypes resilient to stress pressure, smart breeding approaches must be envisaged, including the exploitation of wild relatives. Here we report on the assessment of the breeding potential of six durum wheat-Thinopyrum spp. recombinant lines (RLs) obtained through chromosome engineering. They are characterized by having 23% or 28% of their 7AL chromosome arm replaced by a “nested” alien segment, composed of homoeologous group 7 chromosome fractions from Th. ponticum and Th. elongatum (=7el1L + 7EL) or from different Th. ponticum accessions (=7el1L + 7el2L). In addition to the 7el1L genes Lr19 + Yp (leaf rust resistance, and yellow pigment content, respectively), these recombinant lines (RLs) possess a highly effective QTL for resistance to FHB and FCR within their 7el2L or 7EL portion. The RLs, their null segregants and well-adapted and productive durum wheat cultivars were evaluated for 16 yield-related traits over two seasons under rainfed and irrigated conditions. The absence of yield penalties and excellent genetic stability of RLs was revealed in the presence of all the alien segment combinations. Both 7el2L and 7EL stacked introgressions had positive impacts on source and sink yield traits, as well as on the overall performance of RLs in conditions of reduced water availability. The four “nested” RLs tested in 2020 were among the top five yielders, overall representing good candidates to be employed in breeding programs to enhance crop security and safety.

Aegilops markgrafii (Greuter) Hammer is an important source of genes for resistance to abiotic stresses and diseases in wheat (Triticum aestivum L.). A series of six wheat ‘Alcedo’-Ae. markgrafii chromosome disomic addition lines, designated as AI(B), AII(C), AIII(D), AV(E), AIV(F), and AVIII(G) carrying the Ae. markgrafii chromosomes B, C, D, E, F, and G, respectively, were tested with SSR markers to establish homoeologous relationships to wheat and identify markers useful in chromosome engineering. The addition lines were evaluated for resistance to rust and powdery mildew diseases. The parents Alcedo and Ae. markgrafii accession ‘S740-69’ were tested with 1500 SSR primer pairs and 935 polymorphic markers were identified. After selecting for robust markers and confirming the polymorphisms on the addition lines, 132 markers were considered useful for engineering and establishing homoeologous relationships. Based on the marker analysis, we concluded that the chromosomes B, C, D, E, F, and G belong to wheat homoeologous groups 2, 5, 6, 7, 3, and 4, respectively. Also, we observed chromosomal rearrangements in several addition lines. When tested with 20 isolates of powdery mildew pathogen (Blumeria graminis f. sp. tritici) from five geographic regions of the United States, four addition lines [AIII(D), AV(E), AIV(F), and AVIII(G)] showed resistance to some isolates, with addition line AV(E) being resistant to 19 of 20 isolates. The addition lines were tested with two races (TDBJ and TNBJ) of the leaf rust pathogen (Puccinia triticina), and only addition line AI(B) exhibited resistance at a level comparable to the Ae. markgrafii parent. Addition lines AII(C) and AIII(D) had been previously identified as resistant to the Ug99 race group of the stem rust pathogen (Puccinia graminis f. sp. tritici). The addition lines were also tested for resistance to six United States races (PSTv-4, PSTv-14, PSTv-37, PSTv-40, PSTv-51, and PSTv-198) of the stripe rust pathogen (Puccinia striiformis f. sp. tritici); we found no resistance either in Alcedo or any of the addition lines. The homoeologous relationships of the chromosomes in the addition lines, molecular markers located on each chromosome, and disease resistance associated with each chromosome will allow for chromosome engineering of the resistance genes.

Plant height (PH), branch initiation height (BIH), and stem diameter (SD) are three stem-related traits that play crucial roles in plant architecture and lodging resistance. Herein, we show one doubled haploid (DH) population obtained from a cross between Y689 (one Capsella bursa-pastoris derived Brassica napus intertribal introgression) and Westar (B. napus cultivar) that these traits were significantly positively correlated with one another and with flowering time (FT). Based on a high-density SNP map, a total of 102 additive quantitative trait loci (QTL) were identified across six environments. Seventy-two consensus QTL and 49 unique QTL were identified using a two-round strategy of QTL meta-analysis. Notably, a total of 19 major QTL, including 11 novel ones, were detected for these traits, which comprised two QTL clusters on chromosomes A02 and A07. Conditional QTL mapping was performed to preliminarily evaluate the genetic basis (pleiotropy or tight linkage) of the co-localized QTL. In addition, QTL by environment interactions (QEI) mapping was performed to verify the additive QTL and estimate the QEI effect. In the genomic regions of all major QTL, orthologs of the genes involved in phytohormone biosynthesis, phytohormone signaling, flower development, and cell differentiation in Arabidopsis were proposed as candidate genes. Of these, BnaA02g02560, an ortholog of Arabidopsis GASA4, was suggested as a candidate gene for PH, SD, and FT; and BnaA02g08490, an ortholog of Arabidopsis GNL, was associated with PH, BIH and FT. These results provide useful information for further genetic studies on stem-related traits and plant growth adaptation.

Aegilops markgrafii (Greuter) Hammer is an important source of genes for resistance to abiotic stresses and diseases in wheat (Triticum aestivum L.). A series of six wheat 'Alcedo'- Ae. markgrafii chromosome disomic addition lines, designated as AI(B), AII(C), AIII(D), AV(E), AIV(F), and AVIII(G) carrying the Ae. markgrafii chromosomes B, C, D, E, F, and G, respectively, were tested with SSR markers to establish homoeologous relationships to wheat and identify markers useful in chromosome engineering. The addition lines were evaluated for resistance to rust and powdery mildew diseases. The parents Alcedo and Ae. markgrafii accession 'S740-69' were tested with 1500 SSR primer pairs and 935 polymorphic markers were identified. After selecting for robust markers and confirming the polymorphisms on the addition lines, 132 markers were considered useful for engineering and establishing homoeologous relationships. Based on the marker analysis, we concluded that the chromosomes B, C, D, E, F, and G belong to wheat homoeologous groups 2, 5, 6, 7, 3, and 4, respectively. Also, we observed chromosomal rearrangements in several addition lines. When tested with 20 isolates of powdery mildew pathogen (Blumeria graminis f. sp. tritici) from five geographic regions of the United States, four addition lines [AIII(D), AV(E), AIV(F), and AVIII(G)] showed resistance to some isolates, with addition line AV(E) being resistant to 19 of 20 isolates. The addition lines were tested with two races (TDBJ and TNBJ) of the leaf rust pathogen (Puccinia triticina), and only addition line AI(B) exhibited resistance at a level comparable to the Ae. markgrafii parent. Addition lines AII(C) and AIII(D) had been previously identified as resistant to the Ug99 race group of the stem rust pathogen (Puccinia graminis f. sp. tritici). The addition lines were also tested for resistance to six United States races (PSTv-4, PSTv-14, PSTv-37, PSTv-40, PSTv-51, and PSTv-198) of the stripe rust pathogen (Puccinia striiformis f. sp. tritici); we found no resistance either in Alcedo or any of the addition lines. The homoeologous relationships of the chromosomes in the addition lines, molecular markers located on each chromosome, and disease resistance associated with each chromosome will allow for chromosome engineering of the resistance genes. [ABSTRACT FROM AUTHOR]

Highlights • Th. ponticum 7AgL introgressions onto durum wheat 7AL improve yield-related traits. • 7AgL chromatin significantly increases grain number across contrasting environments. • A major QTL for grain number increase was confirmed in the 28–40% 7AgL interval. • Results validate the use of chromosome engineering for targeted wheat improvement. Abstract Introgressions of Thinopyrum ponticum 7AgL chromosome segments, spanning 23%, 28% and 40% of the distal end of durum wheat 7AL arm, were previously shown to contain multiple beneficial gene(s)/QTL for yield-related traits, in addition to effective disease resistance (Lr19, Sr25) and quality (Yp) genes. In the present study, durum wheat near isogenic recombinant lines (NIRLs), harbouring each of the three introgressions, were included for the first time in multi-location field trials, to evaluate general and environment-specific effects of the alien chromatin on 26 yield-related traits. Results from nine different trials across contrasting environments of Italy, Morocco and South Australia over four years revealed that the overall impact of 7AgL introgressions into the tetraploid wheat background did not incur, except in one environment, a major yield penalty. The effect of the three 7AgL segments on individual yield-contributing traits resulted in significant increases of biomass m−2 (+9%), spike number m−2 (+13%), grain number m−2 (+11%) and spikelet-1 (+8%), as well as a significant decrease in grain weight (−8%). When the separate NIRLs were analysed, each of the three 7AgL segments were associated with specific yield component variation. The effects of the 40%-long segment proved to be the most stably expressed across environments and involved significant increases of spike and grain number m−2 (13% and 15%, respectively), grain number spike-1 (10%) and spike fertility index (46%), though accompanied by a significant decrease in thousand grain weight (−23%). In spite of this trade-off between grain number and grain weight, their interplay was such that in four trials, including drier environments, a grain yield advantage was observed. This evidence, and comparison with the two other NIRLs, substantiates the hypothesized existence of major gene(s)/QTL for grain number in the most proximal 28–40% 7AgL region, exclusive to the 40%-long 7AgL introgression. The present study represents an important validation of the use of chromosomally engineered genetic stocks for durum wheat improvement, targeting not only disease resistance and quality traits but also relevant yield components. [ABSTRACT FROM AUTHOR]

Summary: Despite a long history, the production of useful alien introgression lines in wheat remains difficult mainly due to linkage drag and incomplete genetic compensation. In addition, little is known about the molecular mechanisms underlying the impact of foreign chromatin on plant phenotype. Here, a comparison of the transcriptomes of barley, wheat and a wheat–barley 7HL addition line allowed the transcriptional impact both on 7HL genes of a non‐native genetic background and on the wheat gene complement as a result of the presence of 7HL to be assessed. Some 42% (389/923) of the 7HL genes assayed were differentially transcribed, which was the case for only 3% (960/35 301) of the wheat gene complement. The absence of any transcript in the addition line of a suite of chromosome 7A genes implied the presence of a 36 Mbp deletion at the distal end of the 7AL arm; this deletion was found to be in common across the full set of Chinese Spring/Betzes barley addition lines. The remaining differentially transcribed wheat genes were distributed across the whole genome. The up‐regulated barley genes were mostly located in the proximal part of the 7HL arm, while the down‐regulated ones were concentrated in the distal part; as a result, genes encoding basal cellular functions tended to be transcribed, while those encoding specific functions were suppressed. An insight has been gained into gene transcription in an alien introgression line, thereby providing a basis for understanding the interactions between wheat and exotic genes in introgression materials. [ABSTRACT FROM AUTHOR]

Plant height (PH), branch initiation height (BIH), and stem diameter (SD) are three stem-related traits that play crucial roles in plant architecture and lodging resistance. Herein, we show one doubled haploid (DH) population obtained from a cross between Y689 (one Capsella bursa-pastoris derived Brassica napus intertribal introgression) and Westar (B. napus cultivar) that these traits were significantly positively correlated with one another and with flowering time (FT). Based on a high-density SNP map, a total of 102 additive quantitative trait loci (QTL) were identified across six environments. Seventy-two consensus QTL and 49 unique QTL were identified using a two-round strategy of QTL meta-analysis. Notably, a total of 19 major QTL, including 11 novel ones, were detected for these traits, which comprised two QTL clusters on chromosomes A02 and A07. Conditional QTL mapping was performed to preliminarily evaluate the genetic basis (pleiotropy or tight linkage) of the co-localized QTL. In addition, QTL by environment interactions (QEI) mapping was performed to verify the additive QTL and estimate the QEI effect. In the genomic regions of all major QTL, orthologs of the genes involved in phytohormone biosynthesis, phytohormone signaling, flower development, and cell differentiation in Arabidopsis were proposed as candidate genes. Of these, BnaA02g02560, an ortholog of Arabidopsis GASA4, was suggested as a candidate gene for PH, SD, and FT; and BnaA02g08490, an ortholog of Arabidopsis GNL, was associated with PH, BIH and FT. These results provide useful information for further genetic studies on stem-related traits and plant growth adaptation. [ABSTRACT FROM AUTHOR]

A Triticum timopheevii-derived bread wheat line, Selection G12, was screened with 40 pathotypes of leaf rust pathogen, Puccinia triticina at seedling stage and with two most commonly prevalent pathotypes 77-5 and 104-2 at adult plant stage. Selection G12 showed resistance at both seedling and adult plant stages. Genetic analysis in F, F and F families at the seedling stage revealed that leaf rust resistance in Selection G12 is conditioned by a single incompletely dominant gene. The leaf rust resistance gene was mapped to chromosome 3BL with SSR markers Xgwm114 and Xgwm547 flanking the gene at a distance of 28.3 cM and 6 cM, respectively. Based on the nature of resistance and chromosomal location, it is inferred that Selection G12 carries a new gene for leaf rust resistance, tentatively named as LrSelG12. [ABSTRACT FROM AUTHOR]

The pairing behaviour of the individual chromosome arms of Hordeum vulgare (Hv) with their homoeologous arms of H. bulbosum (Hb) at metaphase I of meiosis in tetraploid Hb × Hv hybrids and the frequencies of recombined Hv chromosome arms in selfed offspring were studied on differentially visualized chromosomes after fluorescent in situ hybridisation. The frequencies of paired Hv-Hb arms in the F2 and F3 hybrids were correlated with the frequencies of recombined Hv chromosomes in progenies. Self-generation of hybrids, the number of Hv and Hb chromosomes, and the number of recombined Hv chromosomes of the hybrids strongly influenced the Hv - Hb pairing frequency in meiosis. Within the offspring of F2 and F3 hybrids both Hv plants and hybrids were detected. In contrast, all progenies of the F4 hybrid were hybrids which exhibited centromere misdivisions. The highest frequencies of homoeologous pairing in hybrids and most recombinants were obtained for the barley chromosome 1HL. Recombinants for 4HL, 5HS, 6HS, and 7HS were rarely found. Meiotic pairing and recombinants involving chromosome 1HS were never observed. The results of this study demonstrate that fertile tetraploid interspecific hybrids with a high intergenomic pairing at meiosis are valuable basic material for introgression breeding in barley. [ABSTRACT FROM AUTHOR]

The capacity of the bread wheat ( Triticum aestivum) genome to tolerate introgression from related genomes can be exploited for wheat improvement. A resistance to powdery mildew expressed by a derivative of the cross-bread wheat cv. Tähti × T. militinae ( Tm) is known to be due to the incorporation of a Tm segment into the long arm of chromosome 4A. Here, a newly developed in silico method termed rearrangement identification and characterization ( RICh) has been applied to characterize the introgression. A virtual gene order, assembled using the GenomeZipper approach, was obtained for the native copy of chromosome 4A; it incorporated 570 4A DArTseq markers to produce a zipper comprising 2132 loci. A comparison between the native and introgressed forms of the 4 AL chromosome arm showed that the introgressed region is located at the distal part of the arm. The Tm segment, derived from chromosome 7G, harbours 131 homoeologs of the 357 genes present on the corresponding region of Chinese Spring 4 AL. The estimated number of Tm genes transferred along with the disease resistance gene was 169. Characterizing the introgression's position, gene content and internal gene order should not only facilitate gene isolation, but may also be informative with respect to chromatin structure and behaviour studies. [ABSTRACT FROM AUTHOR]

Introgression has been achieved from a wild species Oryza minuta (2n = 48, BBCC, Acc No.101141) into O. sativa subsp. indica IR71033-121-15. This introgression line was developed at International Rice Research Institute (IRRI) through embryo rescue as well as three backcrosses using IR31917-45-3-2 as a recurrent parent. These two IR lines resemble each other but differ in several important agronomic traits, which can be attributable to O. minuta introgressions. Out of 530 STS markers tested for introgression analysis, at least 14 introgressed chromosomal segments from O. minuta were detected throughout 12 chromosomes. Most of the introgressed segments were quite small in size, as they were detected by single markers and flanking markers were negative for introgressions. A population from the cross between japonica cultivar Junambyeo and introgressed indica line IR71033-121-15, consisting of 146 plants, was evaluated for ten agronomic traits. Genotyping of F2 lines and phenotyping from both F2 and F3 were considered for QTL analysis. A total of 11 single-locus QTLs (S-QTLs) were identified for ten traits, i.e. days to heading (DTH), panicle number (PN), spikelet fertility (SF), panicle length (PL), spikelet per panicle (SPP), grain length (GL), grain width (GW), grain length to width ratio (GLW) and grain thickness (GT) in both populations. The O. minuta derived alleles of QTLs, spp6, gl3, glw3, glw5 and t12 were detected in both populations indicating robust QTLs for these traits. QTLs from O. minuta introgression could be new sources of natural genetic variation for genetic improvement of rice.

A pair of stripe rust and leaf rust resistance genes was introgressed from Aegilops caudata, a nonprogenitor diploid species with the CC genome, to cultivated wheat. Inheritance and genetic mapping of stripe rust resistance gene in backcross-recombinant inbred line (BC-RIL) population derived from the cross of a wheat- Ae. caudata introgression line (IL) T291-2(pau16060) with wheat cv. PBW343 is reported here. Segregation of BC-RILs for stripe rust resistance depicted a single major gene conditioning adult plant resistance (APR) with stripe rust reaction varying from TR-20MS in resistant RILs signifying the presence of some minor genes as well. Genetic association with leaf rust resistance revealed that two genes are located at a recombination distance of 13%. IL T291-2 had earlier been reported to carry introgressions on wheat chromosomes 2D, 3D, 4D, 5D, 6D and 7D. Genetic mapping indicated the introgression of stripe rust resistance gene on wheat chromosome 5DS in the region carrying leaf rust resistance gene LrAc, but as an independent introgression. Simple sequence repeat (SSR) and sequence-tagged site (STS) markers designed from the survey sequence data of 5DS enriched the target region harbouring stripe and leaf rust resistance genes. Stripe rust resistance locus, temporarily designated as YrAc, mapped at the distal most end of 5DS linked with a group of four colocated SSRs and two resistance gene analogue (RGA)-STS markers at a distance of 5.3 cM. LrAc mapped at a distance of 9.0 cM from the YrAc and at 2.8 cM from RGA-STS marker Ta5DS_2737450, YrAc and LrAc appear to be the candidate genes for marker-assisted enrichment of the wheat gene pool for rust resistance. [ABSTRACT FROM AUTHOR]

Backcross substitution of Brassica juncea (2n = 36; AABB) nucleus into the cytoplasm of a wild crucifer, Brassica fruticulosa helped in development of a new cytoplasmic male sterility (CMS) system. Male sterility was complete, stable, and expressed as rudimentary anthers containing sterile pollen grains. There was no impact on other floral as well as vegetative characters. All the natural B. juncea genotypes evaluated maintained the sterility. Gene for fertility restoration could be successfully introgressed from cytoplasm donor species. Genomic in situ hybridization studies revealed B. fruticulosa intogression in at least three chromosomes of the recipient species. Genetic studies carried out on F, F and test cross progenies derived from hybridizing cytoplasmic male sterile and fertility restoring genotypes revealed a monogenic dominant control for the fertility restoration. Bulked segregant analysis with 588 SSR and 30 ISSR primers allowed identification of putative primers associated with fertility restoration. Co-segregation analysis of ten such primers with Rff gene revealed that Rf was flanked by two markers, namely cnu_m316 and nia_ m22, which were located 27.1 (LOD = 3.0) and 19.7 cM (LOD = 3.0) respectively around the gene in question. Distinctness of new CMS system from the ogura CMS was also demonstrated. This newly developed CMS-fertility-restorer system has a significant potential for hybrid seed production programs in mustard as an alternative to currently popular ogura CMS system. [ABSTRACT FROM AUTHOR]

Main conclusion: New wheat- Secale africanum chromosome 5R substitution and translocation lines were developed and identified by fluorescence in situ hybridization and molecular markers, and chromosome 5R specific genes responsible for grain hardness were isolated. The wild species, Secale africanum Stapf. (genome RR), serves as a valuable germplasm resource for increasing the diversity of cultivated rye ( S. cereale L., genome RR) and providing novel genes for wheat improvement. In the current study, fluorescence in situ hybridization (FISH) and molecular markers were applied to characterize new wheat- S. africanum chromosome 5R derivatives. Labeled rye genomic DNA (GISH) and the Oligo-probes pSc119.2 and pTa535 (FISH) were used to study a wheat- S. africanum amphiploid and a disomic 5R (5D) substitution, and to identify a T5DL.5RS translocation line and 5RS and 5RL isotelosome lines. Twenty-one molecular markers were mapped to chromosome 5R arms which will facilitate future rapid identification of 5R introgressions in wheat backgrounds. Comparative analysis of the molecular markers mapped on 5R with homoeologous regions in wheat confirmed a deletion on the chromosome T5DL.5RS, which suggests that the wheat- S. africanum Robertsonian translocation involving homologous group 5 may not be fully compensating. Complete coding sequences at the paralogous puroindoline-a ( Pina) and grain softness protein gene ( Gsp- 1) loci from S. africanum were cloned and localized onto the short arm of chromosome 5R. The S. africanum chromosome 5R substitution and translocation lines showed a reduction in the hardness index, which may be associated with the S. africanum- specific Pina and Gsp- 1 gene sequences. The present study reports the production of novel wheat- S. africanum chromosome 5R stripe rust resistant derivatives and new rye-specific molecular markers, which may find application in future use of wild Secale genome resources for grain quality studies and disease resistance breeding. [ABSTRACT FROM AUTHOR]