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Seven synthetic hexaploid wheats (Triticum dicoccum/Aegilops tauschii) were subjected for investigation. Numerical variation of chromosome number in F 1 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 BA u -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.

The production and isolation of a wheat-Aegilops geniculata disomic addition line and of monosomic substitution line resistant to powdery mildew at the seedling and adult plant stages are described. Cytological analysis revealed the presence of an acrocentric chromosome in the resistant derivatives. Polyacrylamide gel electrophoretic analysis indicated differences in the β-zone of the reduced by mercaptoethanol treatment seed protein pattern between the wheat parent cv. Trakya and the resistant derivatives. A component with a high staining intensity in the β-zone was assumed to be a marker for the chromosome 6 of Ae. geniculata. The isoenzyme activity at the Got-1 and Est-4 loci of the lines was lower than that of wheat. By analyzing the isoenzymes of the Amp-1 locus of the addition plants, a quantitative marker of Ae. geniculata 6U chromosome was identified. The progeny of the plants with the 2n = 43 and 2n = 42 chromosomes carrying the chromosome 6U added or mono-substituted for the wheat 6D chromosome segregated for powdery mildew resistance. The mono-and/or double conditions for this chromosome could be maintained by selecting resistant plants in the segregated populations.Key Words: Aegilops geniculata, wheat, powdery mildew resistance, isoenzymes, chromosome 6U. IntroductionPowdery mildew is a destructive foliar disease caused by a biotrophic parasitic fungus Blumeria graminis f. sp. tritici (syn. Erysiphe graminis f. sp. tritici) (Speer 1973). Although chemicals are effective against this disease, the use of host resistance has remained an economical and environmental safe device of control in practice.Genes for powdery mildew resistance, i.e. Pm genes have been described at 33 loci in common wheat (Liu et al. 2002, Singrun et al. 2004, Zhu et al. 2005. Some of them have been utilized in commercial wheat varieties, but were soon overcome by new pathogen races. Strategies including cultivar mixing, diversification or gene pyramiding may increase the resistance to powdery mildew (Priestley and Bayles 1998, Hsam and.The genus Aegilops comprises 22 species, most of which are potential donors of resistance to foliar diseases (Van Stageren 1994, Valkoun and Bedo 2001, Zaharieva et al. 2003. One of them is Aegilops geniculata Roth (syn. Ae. ovata L.), a wild allotetraploid species (2n = 28, UUMM). The species can be crossed to common wheat, and various derivatives such as addition, substitution and translocation lines have been obtained (Mettin et al. 1977, Friebe and Heun 1989, Friebe et al. 1996, McIntosh et al. 2001. Up to now, only the Pm29 gene from Ae. geniculata had been transferred to common wheat . However, the resistance could not be traced back to a specific chromosome, because of the high level of structural variation in the chromosome complements of the A and B genomes of the addition lines (Friebe and Heun 1989).Identification of alien introgressions has been greatly facilitated by the use of seed storage protein patterns and isoenzymes as markers of alien genes in the wheat background and for det...