Chromosome variation and HMW glutenins in synthetic hexaploid wheats (Triticum turgidum ssp. dicoccum/Aegilops tauschii)

Seven synthetic hexaploid wheats (Triticum dicoccum/Aegilops tauschii) were subjected for investigation. Numerical variation of chromosome number in F1 hybrids between three synthetics and common wheat varieties, was recorded. Hexaploid amphiploids (SHW) formed gametes with aneuploid chromosome number at a frequency of 13.2 and 14.8% as male and female parents, respectively. We speculated that the frequency of aneuploids in the generation might depend on variability of BAu- and D-genomes of synthetic parents, and could be used for increasing the genetic diversity in common wheat. The HMW-glutenins analysis divided two lines in SHW530 and 532 due to different genes present in the B-genome, and increased them to 9 synthetic lines. The subunits 1Dx1.5 + 1Dy10 was predominantly observed in the synthetics. Two other allelic variants 1Dx2 + 1Dy11 and 1Dx4 + 1Dy10.1 were found in four lines and appeared as new genes in SHW originated from Aegilops tauschii. The synthetic hexaploid lines could play a significant role as novel germplasm resources for improving the grain quality of bread wheat

POLYMORPHISM OF ENDOSPERM PROTEINS IN AMPHIDIPLOIDS WITH THE G GENOME OF Triticum timopheevii (Zhuk.)

During evolution in Triticum the diversity of genes in T. aestivum L. was greatly reduced compared to its ancestors. This tendency restricted further improvement of productivity and quality in common wheat and narrowed the plant resistance to biotic and abiotic stresses. Wide hybridization resulted in synthetic genotypes that offered opportunities for introduction of new genes for useful traits in breeding. The objects of this study were two amphidiploids with G-genome inherited from tetraploid wheat relative T. timopheevii (2n=28, GGAuAu). Glutenin and gliadin allelic composition of the synthetic wheats H-68/44 and H-69/36 were analysed by SDS-PAGE and A-PAGE electrophoretic methods. New allelic variants in Glu-G1 loci, which are not characteristics for the spectrum of T. aestivum, were identified. In contrast to the high polymorphism of amphidiploids for high-molecular weight proteins, variation in the low-molecular glutenins was much less. More gliadin alleles in synthetic lines were found than in hexaploid wheat, due to the parent polymorphism. The results of this survey showed that synthetics with T. timopheevii genome might serve as an important sources of increased genetic variation for endosperm proteins in common wheat

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

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 F2 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 F4–6 from SHW8ATb/ 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

Anther culture response of Triticum durum × T. monococcum ssp. aegilopoides amphiploid

Two durum wheat varieties, Saturn-1 and Neptun-2, were used in the production of Triticum durum × Triticum monococcum ssp. aegilopoides amphiploid (AABBA m A m ), thus generating two amphiploid lines, designated A1 and A2, respectively. Anther culture response was studied involving callus induction, plant regeneration, albino- and green plants produced. The wild wheat parent did not respond to any of the parameters studied while the tetraploid wheats yielded only albino plants. Amphiploid lines differed in between for plant regeneration ability and produced albino and green plants, ranging from 1.9–3.2 and 0.4–0.8 per 100 plated anthers, respectively. Thus, the lines reacted equally in androgenesis for green plant yields and might be of use in the haploid wheat production