Development and characterization of a line with substitution of chromosome 4B of wheat Triticum aestivum L. on chromosome 4Hmar of wild barley Hordeum marinum ssp. gussoneanum (4x)

Introgressive hybridization is the main method of broadening the genetic diversity of bread wheat. Wild barley Hordeum marinum ssp. gussoneanum Hudson (2n = 4x = 28) has useful agronomical traits, such as high resistance to stress factors, that could be a potential source of new genes for bread wheat improvement. This study aimed to evaluate the possibility of introgression of H. marinum chromosomes into the genome of bread wheat using an incomplete amphiploid H. marinum ssp. gussoneanum (4x)-T. aestivum (Pyrotrix 28) (2n = 54) carrying the cytoplasm of wild barley. For this purpose, we crossed the line of bread wheat variety Pyrotrix 28 with an incomplete amphiploid, and then selected cytogenetically stable 42-chromosome plants with a high level of fertility in hybrid progeny. Genomic in situ hybridization (GISH) revealed a pair of H. marinum chromosomes in the genome of these plants. C- banding analysis confirmed that bread wheat chromosome 4B was replaced by wild barley chromosome 4Hmar. SSR markers Xgwm368 and Xgwm6 confirmed the absence of chromosome 4B, and EST markers BAWU808 and BAW112 identified chromosome 4Hmar in the genome of the isolated disomic wheat-barley substitution line. The study of this line showed that the substitution of chromosome 4B with chromosome 4Hmar resulted in a change of some morphological traits. It included intense anthocyanin coleoptile coloration, specific for H. marinum, as well as a lack of purple coloration of the ears in the leaf sheath, specific for Pyrotrix 28. Line 4Hmar(4B) showed increased performance for several traits, including plant height, number of spikes and tillers per plant, spikelet and grain number in the main spike, grain number per plant, but it had decreased values of 1000-grain weight compared to wheat. Cytogenetic stability and fertility of line 4Hmar(4B) indicated a high compensation ability of barley 4Hmar for wheat chromosome 4B and confirmed their homeology.

Genetic classification of Aegilops columnaris Zhuk. (2n=4x=28, UcUcXcXc) chromosomes based on FISH analysis and substitution patterns in common wheat × Ae. columnaris introgressive lines

Aegilops columnaris is a tetraploid species originated from Ae. umbellulata (2n=2x=14, UU) and a yet unknown diploid grass species. Although Ae. columnaris possesses some agronomically valuable traits, such as heat and drought tolerance and resistance to pests, it has never been used in wheat breeding because of difficulties in producing hybrids and a lack of information on the relationships between Ae. columnaris and common wheat chromosomes. In this paper, we report the development of 57 wheat - Ae. columnaris introgressive lines covering 8 of the14 chromosomes of Aegilops. Based on substitution spectra of hybrids and the results of FISH analysis of the parental Ae. columnaris line with seven DNA probes, we have developed the genetic nomenclature of the U^c and X^c chromosomes. Genetic groups and genome affinities were established for 11 of 14 chromosomes; the classification of the remaining three chromosomes remains unsolved. Each Ae. columnaris chromosome was characterized on the basis of C-banding pattern and the distribution of seven DNA sequences. Introgression processes were shown to depend on the parental wheat genotype and the level of divergence of homoeologous chromosomes. We found that lines carrying chromosome 5X^c are resistant to leaf rust; therefore, this chromosome could possess novel resistance genes that have never been utilized in wheat breeding.