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Modern hexaploid wheat (Triticum aestivum L.; AABBDD) has evolved from a hybrid of tetraploid wheat (closely related to Triticum turgidum L. ssp. durum (Desf.) Husn., AABB) and goatgrass (Aegilops tauschii Coss., DD). Variations in chromosome structure and ploidy have played important roles in wheat evolution. How these variations occur and their role in expanding the genetic diversity of modern wheat remain largely unknown. Synthetic hexaploid wheat (SHW) can be used to investigate chromosome variations that occur during the early generations of existence. SHW lines derived by crossing durum wheat 'Langdon' with 12 Ae. tauschii accessions were analyzed using oligonucleotide probe multiplex fluorescence in situ hybridization (FISH) of metaphase chromosomes and SNP markers. Cluster analysis based on SNP markers categorizes them into three groups. Among 702 plants from the [S.sub.8] and [S.sub.9] generations, 415 (59.12%) carried chromosome variations involving all 21 chromosomes, but with different frequencies for each chromosome and sub-genome. Total chromosome variation frequencies varied between lines, but there was no significant difference among the three groups. The non-random chromosome variations in the SHW lines detected in this study may indicate that similar variations occurred in the early stages of wheat polyploidization and played important roles in wheat evolution. Key words: Triticum aestivum, Triticum turgidum, Aegilops tauschii, chromosome evolution, oligonucleotide probe multiplex FISH. Le ble hexaplo'ide moderne (Triticum aestivum L.; AABBDD) a evolue a partir d'un hybride entre un ble tetraplo'ide (tres apparente au Triticum turgidum L. ssp. durum (Desf.) Husn., AABB) et l'egilope de Tausch (Aegilops tauschii Coss., DD). Les variations dans la structure des chromosomes et la plo'idie ont joue des roles importants dans revolution du ble. Comment ces variations sont survenues et leur role dans l'expansion de la diversite genetique chez les bles modernes demeure largement inconnu. Des bles hexaplo'ides synthetiques (SHW) peuvent servir a etudier la variation chromosomique qui survient dans les premieres generations suivant leur synthese. Des lignees SHW derivees de croisements entre le ble dur 'Langdon' et douze accessions de l'Ae. tauschii ont ete analysees au moyen de marqueurs SNP et d'hybridations in situ en fluorescence (FISH) realisees en employant un multiplexe de sondes oligonucleotidiques sur des chromosomes en metaphase. Des analyses de groupement fondees sur les marqueurs SNP ont permis de categoriser en trois groupes. Parmi les702plantesissuesdesgenerations[S.sub.8] et [S.sub.9], 415 (59,12 %) presentaient une variation chromosomique et les 21 chromosomes etaient concernes par cette variation, mais les frequences pour chaque chromosome et sousgenome etaient variables. Les frequences totales en matiere de variation chromosomique differaient selon les lignees, mais aucune difference significative entre les trois groupes n'a ete trouvee. Les variations chromosomiques non-aleatoires chez les lignees SHW detectees dans ce travail indiquent possiblement qu'une variation semblable est survenue dans les premiers stades de la polyploidisation chez le ble et aurait joue des roles importants dans revolution du ble. [Traduit par la Redaction] Mots-cles : Triticum aestivum, Triticum turgidum, Aegilops tauschii, evolution des chromosomes, FISH employant un multiplexe de sondes oligonucleotidiques., Introduction Polyploidization is a frequent evolutionary event in many eukaryotes (Soltis and Kliebenstein 2015; Van de Peer et al. 2017) that facilitates genome evolution through rapid genetic and epigenetic changes [...]

Successful strategies that can contribute to poverty reduction and improve the livelihoods of the poor, particularly in Sub-Saharan Africa (SSA), are critically needed to address the technology adoption constraints. The objectives of this study were to assess the adoption level of improved technologies and management practices and to identify the key factors influencing their adoption in the major wheat-producing areas in the irrigated, arid, and heat-prone environments of Sudan. A farm survey was conducted in 2021 using a structured questionnaire that included almost all recommended technological options for optimum and sustainable wheat production. A total of 300 farmers, 93, 101, and 106 from Northern (NS), Kassala (KS), and Gezira (GS) states, respectively, were selected and interviewed. Besides descriptive statistics, a binary logistic model was used to identify the socioeconomic and production factors affecting farmers' perceptions of improved and recommended technological options. The study found a wide range of adoption rates depending on the specific technology practice and the area surveyed. The lowest adoption rate was observed for land preparation (6.5%) in NS. Adoption rates ranging from 26–100% were observed for technologies such as the sowing date, the seed rate, seed treatment, the awareness of released varieties, nitrogen and phosphorus fertilizer application, and chemical weed control. The difference in the productivity of technological option adopters was significant (p = 0.015) compared to non-adopters. The binary logistic regression results showed that five out of seven explanatory variables hypothesized to influence wheat farmers' perceptions on the decision to adopt improved and recommended technologies significantly influenced farmers' decision to adopt the technologies. In particular, access to quality seeds, financial credit, and extension services were found to be the most critical determinants of adopting improved technologies. Approaches that bring together all stakeholders along the crop value chain, including policymakers, to jointly analyze, identify, and prioritize challenges and develop and apply solutions and work plans using feedback and learning mechanisms are expected to increase farmer awareness and adoption of improved technologies, ultimately leading to sustainable wheat production. [ABSTRACT FROM AUTHOR]

Global warming has led to the expansion of arid lands and more frequent droughts, which are the largest cause of global food production losses. In our previous study, we developed TaPYLox wheat overexpressing the plant hormone abscisic acid (ABA) receptor, which is important for the drought stress response in plants. TaPYLox showed resistance to drought stress and acquired water-saving traits that enable efficient grain production with less water use. In this study, we used TaPYLox to identify ABA-dependent and -independent metabolites in response to drought stress. We compared the variation of metabolites in wheat under well-watered, ABA treatment, and drought stress conditions using the ABA-sensitive TaPYLox line and control lines. The results showed that tagatose and L-serine were ABA-dependently regulated metabolites, because their stress-induced accumulation was increased by ABA treatment in TaPYLox. In contrast, L-valine, L-leucine, and DL-isoleucine, which are classified as branched chain amino acids, were not increased by ABA treatment in TaPYLox, suggesting that they are metabolites regulated in an ABA-independent manner. Interestingly, the accumulation of L-valine, L-leucine, and DL-isoleucine was suppressed in drought-tolerant TaPYLox under drought stress, suggesting that drought-tolerant wheat might be low in these amino acids. 3-dehydroshikimic acid and α-ketoglutaric acid were decreased by drought stress in an ABA-independent manner. In this study, we have succeeded in identifying metabolites that are regulated by drought stress in an ABA-dependent and -independent manner. The findings of this study should be useful for future breeding of drought-tolerant wheat. [ABSTRACT FROM AUTHOR]

The inoculation of Epichloë endophytes into modern cereals, resulting in systemic infection, depends on the genetics of both the host and the endophyte strain deployed. Until very recently, the only modern cereal to have been infected with Epichloë, in which normal phenotype seed-transmitted associations were achieved, is rye (Secale cereale). Whilst minor in-roads have been achieved in infecting hexaploid wheat (Triticum aestivum), the phenotypes of these associations have all been extremely poor, including host death and stunting. To identify host genetic factors that may impact the compatibility of Epichloë infection in wheat, wheat–alien chromosome addition/substitution lines were inoculated with Epichloë, and the phenotypes of infected plants were assessed. Symbioses were identified whereby infected wheat plants were phenotypically like uninfected controls. These plants completed their full lifecycle, including the vertical transmission of Epichloë into the next generation of grain, and represent the first ever compatible wheat–Epichloë associations to be created. [ABSTRACT FROM AUTHOR]

Chromosome engineering is an important approach for generating wheat germplasm. Efficient development of chromosome aberrations will facilitate the introgression and application of alien genes in wheat. In this study, zebularine, [...]