Grain quality of bread spring wheat hybrid lines - descendants of hybrids of synthetics with the variety Kharkivska 26

Relevance. The problem of selection improvement of wheat in terms of grain quality is currently relevant. One of the genetic sources for improving grain quality are amphidiploids obtained by hybridizing tetraploid wheat species with the wild related species Aegilops tauschii Coss. (in the world literature they are now referred to as synthetics or synthetic hexaploids - SH). Purpose of the study was to evaluate the grain quality indicators of 29 introgression lines obtained by hybridization of synthetic hexaploids Triticum durum Desf. - Aegilops tauschii Coss. and T.persicum Vav. – Ae.tauschii with bread spring wheat variety Kharkivska 26. Methods. Protein content, gluten content, gluten quality according to gluten deformation index (GDI) in grain grown in different weather conditions - 2015, 2016, 2017, and protein content also in 2020, were analyzed.The analysis of grain quality was carried out in the Laboratory of genetics, biotechnology and grain quality of the Plant Production Institute named after V.Ya. Yuriev of NAAS. The protein content in the grain was determined using an InfraLUM FT-10 device. The gluten quality was determined using an VDK-1 M device. The trait indicators were evaluated on a scale: 0-15 - group III, unsatisfactorily strength; 20-40 - group II, satisfactorily strength; 45-75 - group I, good; 80-100 - group II, satisfactorily weak; 105-120 - group III, unsatisfactorily weak. Evaluation of ecological plasticity and stability was carried out according to the method of Eberhart S.A. and Russel W.A. (1966). Results. The protein content in the grain of the studied lines varied depending on the year conditions. 2017 and 2015 were favorable for the manifestation of the trait being characterized by less precipitation during the period of grain ripening; unfavorable was 2020 - the most humid; intermediate was 2016. The average rate of recurrent variety Kharkivska 26 was 14.6%. The highest protein content was noted in the lines DK 26 and DK 22, respectively, 16.4% and 15.9%. The following lines also exceeded the recurrent variety: DK 4, DK 21, DK 23, DK 30, DK 37, DK 39, DK 44, DK 48, DK 50, DKS 16, DKS 18, DKS 19. The lines of DKS 14 and DKS 15 had the lowest protein content – respectively 12.8% and 13.0%. The lines DK 25, DK 27, DK 39, DK 44 showed relatively high rates of reaction to the year conditions – the plasticity (bi from 1.69 to 2.18). Of these, more stable in the trait manifestation are DK 25 and DK 27: sd is 0.34 and 0.58, respectively. The years 2015 and 2017 were more favorable for gluten accumulation as well as for the protein content, 2016 was unfavorable one. The highest content of crude gluten – from 30.5% to 34.3% – was showed for the lines DK 21, DK 22, DK 26, DK 39, DKS 16, DKS 17, DKS 19 whereas the average grade of Kharkivska 26 was of 27.5%. Of these, DK 21, DK 22, DK 26, DKS 16, DKS 19 were also high in protein. The reaction to year conditions of most lines was characterized by a regression coefficient bi from 0.8 to 1.6 at the rate of Kharkivska 26 of 1.5. The greatest variation showed the line DK 7. The combination of the reaction to year conditions a stable trait manifestation showed DK 22 and DKS 19: bi would be 1.1 and 1.4, sd - 0.00 and 0.01, respectively. In terms of gluten quality, 12 lines are assigned to the first - the best group. Most of the lines, as well as the Kharkivska 26 variety, belonged to group II - satisfactorily weak. Of the samples of the Ist group, the lines DK 47, DKS 12, DKS 13, DKS 18 were more stable on this trait as compared to others. The lines DK 21, DKS 16, DKS 18, in addition to the gluten quality, were also distinguished by the content of protein and gluten; the lines DK 23 and DK 30 – by protein content; DKS 17, DKS 20 – by the gluten content. Analysis of pedigrees shows that among the lines identified for each of the three traits, there are descendants of all synthetics. Therefore, the involvement of synthetics as such is promising for improving grain quality indicators. In our experiments, the protein and gluten content in most lines was higher in the drier years - 2015 and 2017. In the same years, the GDI was usually lower, and therefore closer to better. It should be noted that the parameters by which the lines are selected correspond to the baking properties of the grain. Samples with low protein and low gluten can be valuable for the manufacture of other products - cookies, pita, etc. Thus, the results of our research proved the prospects of using synthetics as a source of grain quality improvement in the selection of spring soft wheat. Perspectives. It is concluded that the use of synthetics is promising as a source of traits for improving the wheat grain quality. The selected lines should be used as sources of grain quality traits for breeding, as well as material for productivity testing in order to include the best of them in variety testing nurseries. The lines with low protein content and weak gluten can be valuable for making specific products - biscuits, pita bread and the like.

Evolution of the bread wheat D-subgenome and enriching it with diversity from Aegilops tauschii

Aegilops tauschii, the diploid wild progenitor of the D-subgenome of bread wheat, constitutes a reservoir of genetic diversity for improving bread wheat performance and environmental resilience. To better define and understand this diversity, we sequenced 242 Ae. tauschii accessions and compared them to the wheat D-subgenome. We characterized a rare, geographically-restricted lineage of Ae. tauschii and discovered that it contributed to the wheat D-subgenome, thereby elucidating the origin of bread wheat from at least two independent hybridizations. We then used k-mer-based association mapping to identify discrete genomic regions with candidate genes for disease and pest resistance and demonstrated their functional transfer into wheat by transgenesis and wide crossing, including the generation of a library of ‘synthetic’ hexaploids incorporating diverse Ae. tauschii genomes. This pipeline permits rapid trait discovery in the diploid ancestor through to functional genetic validation in a hexaploid background amenable to breeding.

Phenotypic effects of Am genomes in nascent synthetic hexaploids derived from interspecific crosses between durum and wild einkorn wheat

Background Allopolyploid speciation is a major evolutionary process in wheat (Triticum spp.) and the related Aegilops species. The generation of synthetic polyploids by interspecific crosses artificially reproduces the allopolyploidization of wheat and its relatives. These synthetic polyploids allow breeders to introduce agriculturally important traits into durum and common wheat cultivars. This study aimed to evaluate genetic and phenotypic diversity in wild einkorn (Triticum monococcum ssp. aegilopoides) accessions, to generate a set of synthetic hexaploid lines containing the various Am genomes from wild einkorn, and to reveal their agronomic characteristics.Results We examined the genetic diversity of 43 wild einkorn accessions using simple sequence repeat markers covering all the chromosomes and revealed two genetically divergent lineages, L1 and L2. The genetic divergence between these lineages was linked to their phenotypic divergence and the climate of their habitats. L1 accessions were characterized by early flowering, fewer spikes, large spikelets, and low-density spikelets compared to L2 accessions. These trait differences could have resulted from adaptation to their different habitats. We then developed 42 synthetic lines containing the AABBAmAm genome through interspecific crosses between T. turgidum cv. Langdon (AABB genome) as the female parent and the wild einkorn accessions (AmAm genome) as the male parents. Two of the 42 AABBAmAm synthetic lines exhibited hybrid dwarfism. Phenotypic variation, especially for days to flowering and spikelet-related traits, in the synthetic lines was significantly correlated with that in their wild einkorn parents. The phenotypic divergence between L1 and L2 accessions also reflected phenotypic differences among the synthetic lines. Furthermore, the AABBAmAm synthetic lines had longer spikelets and grains, long awns, high plant heights, soft grains, and late flowering, which are distinct from other synthetic hexaploid wheat lines such as AABBAA and AABBDD. Conclusions Wild einkorn genetically and phenotypically diverged into two lineages. The phenotypic variations in the synthetic lines reflected the divergence among wild einkorn. Utilization of various Am genomes of wild einkorn resulted in wide phenotypic diversity in the AABBAmAm synthetic hexaploids and provides promising new breeding materials for wheat.