Progress in tetraploid wheat breeding through the use of synthetic hexaploid amphiploids

Abstract

Four amphiploid lines (SHW) based on T. monococcum (Tm) and T. boeoticum (Tb) were crossed to T. durum varieties to generate 13 combinations. Field germination and winter survival of hybrid plants in F 2 were assessed. Among all crosses, those with SHW8A-Tb and SHW9A-Tm showed highest field germination but with different degrees of spike fragility. The variation on seed number and weight per main spike was studied in F 4-6 from SHW8A-Tb/Progres and SHW5A-Tb/Severina crosses after individual selection for these traits. Ten lines with durum phenotype from the former and three genotypes with dicoccum plant shape from the latter cross were developed. SDS-PAGE indicated the presence of HMW-GS 1Ax2*+1Aynull subunits in four lines, among which 1Ax2* was inherited from T. boeoticum acc.110 through SHW8A-Tb. Most of the selected genotypes possessed γ-gliadin45, which was relating to good end-use quality. Powdery mildew testing showed that all progenies resulted from the SHW8A-Tb/Progres were susceptible to 12 races of the pathogen, while three lines derived from the SHW5A-Tb/Severina cross behaved differently: G32 expressed resistance to six, G33 to 2, and G34 to 5 races. The selected genotypes from crosses involving SHW with T. boeoticum exhibited good breeding performance compared to tetraploid wheat parents, and might be of breeding interest to further research.

Characterisation of synthetic hexaploid wheat (BBAuAuAmAm) and its potential use in wheat breeding

“…We succeeded to transfer the same A1x2*+A1y1 subunit pair from T. boeoticum into four durum wheat progenies through the amphiploid SHW8A-Tb. Most of the selected durum genotypes possessed γ-gliadin45, relating to a good end-use quality (Daskalova et al, 2019). Thus, the A b genome from diploid Triticum species offers new possibilities to enrich the wheat genetic basis.…”

“…If the top spikelets disintegrated, the plant was marked as fragile one. The brittleness occurred only at the apical spikelets of the spike, which makes this manual action easy to divide a fragile vs not fragile plant (Daskalova et al, 2019). Every year, seeds from two plants with resistance to spike fragility are used for sowing.…”

“…The obtained F 1 hybrids (2n = 3x = 21) are treated with colchicine for chromosome doubling and production of fertile hexaploid genotypes known as synthetic hexaploid wheats (SHW) (Daskalova et al, 2016a). SHW involving diploid wheat species are often called A-genome amphiploids possessing an enormous variability to biotic and abiotic stresses (Ahmed et al, 2014a;Daskalova et al, 2019). References for SHW with T. sinskajae are very exiquous.…”

Allelic Variation of High-Molecular-Weight Glutenin Genes in <i>Triticum</i> Species and Triticale (× <i>Triticosecale</i> Wittmack)

“…This was also observed in a cross between a T. urartu accession and durum wheat cv. Yavaros and 1Ax2* + 1Ay-null subunits transferred from T. boeoticum through synthetic hexaploid wheat 8A-Tb into durum background [21,22]. Due to the single accession of T. sinskajae involved in investigations, the published data are scarce.…”