The study of agronomical traits determining productivity of Triticum aestivum/Triticum timopheevii introgression lines with resistance to fungal diseases

Development of resistant cultivars is one of the effective ways for protection of common wheat T. aestivum L. from fungal pathogens. The gene pool of wild and cultivated wheat relatives is often used for widening the wheat genetic diversity of resistance genes. However, alien genetic material introgressed into the wheat genome can contain genetic factors negatively affecting agronomically important traits. T. aestivum/ T. timopheevii introgression lines derived from different common wheat cultivars have characteristically good resistance to leaf rust and powdery mildew. A comparative assessment of these lines and initial wheat varieties during four field seasons revealed a significant effect of environmental factors on the phenotypic differences between traits that have relevance to productivity. Averaged data obtained for individual introgression lines and for cross combinations revealed both positive and negative tendencies in variations of agronomical traits. The positive effects include a significant increase in the numbers of tillers and spikelets per spike of the lines derived from cv. Skala. Reduction in spike productivity was found in groups of the lines derived from cv. Tselinnaya 20 and cv. Novosibirskaya 67. However, no significant differences in 1000-grain weight were found between most lines and original wheat cultivars. Analysis of the data obtained showed no apparent correlation between the reduction of agronomic traits and the amount of alien genetic material introgressed into the common wheat genome. T. aestivum/T. timopheevii introgression lines can be used as a source of resistance genes without reducing the yield of wheat cultivars

ANALYSYS OF THE CORRELATION BETWEEN WHEAT DOUGH STRENGTH AND STORAGE PROTEINS

We analyzed the hexaploid wheat cultivars Saratovskaya 29, Novosibirskaya 67, Skala, Irtyshanka 10, and Tselinnaya 20 and their introgression lines with Triticum timofeevii Zhuk. to elucidate the correlation between dough rheological properties (dough strength) and the contents of overall protein, raw gluten, gliadin, glutenin. The ratio of glutenin and gliadin contents and their increment in the introgression lines in comparison with the parent cultivars were assessed. Dough strength was found to correlate significantly only with glutenin increase. This correlation can be utilized in breeding design

Development and Genetic Analysis of Common Wheat Introgressive Lines Resistant to Leaf Rust

Transfer of genetic material from tetraploid species, Triticum timopheevii Zhuk, resistant to diseases into common wheat Triticum aestivum L. has been carried out. Six common wheat cultivars were used. The process of hybrid forms stabilization have been studied in details; identification of Triticum timopheevii genetic material in genome of introgressive lines (2n = 42) resistant to leaf rust (Puccinia triti- cina Erikss.) has been carried out. Donors of rust resistance have been developed and the genetic control of the character has been studied. The resistance of obtained lines has been shown to be due to Lr genes, non- allelic to effective Lr genes from world collection

Microsatellite mapping of a leaf rust resistance gene transferred to common wheat from Triticum timopheevii

A leaf rust resistance gene transferred from the tetraploid wheat Triticum timopheevii (Zhuk.) Zhuk. (genomic composition: A t A t GG) into common wheat Triticum aestivum L. conditioned resistance at the seedling and adult plant stages in the introgression line ‘line 842-2’. To determine chromosome location and to map the resistance gene an F 2 population from a cross between ‘line 842-2’ and susceptible wheat cultivar ‘Skala’ was developed and screened against leaf rust pathotype 77 ( Puccinia triticina Erikss.). Microsatellite markers detected introgressions of the T. timopheevii genome on chromosomes 1A, 2A, 2B, 5B and 6B of ‘line 842-2’. Linkage analysis revealed an association between leaf rust resistance and microsatellite markers located on chromosome 5B. The markers Xgwm880 and Xgwm1257 were closely linked to the resistance gene with genetic distances of 7.7 cM and 10.4 cM, respectively. Infection type tests with three leaf rust isolates resulted in different patterns of infection types of ‘line 842-2’ and ‘Thatcher’ near-isogenic line with the Lr18 gene on chromosome 5B. The data corroborated the hypothesis of the diversity of the resistance coming from T. timopheevii . The resistance gene of the introgression ‘line 842-2’ seems to be different than Lr18 and therefore it was designated LrTt2

MOLECULAR DIVERSITY OF COMMON WHEAT INTROGRESSION LINES (T. AESTIVUM / T. TIMOPHEEVII)

Genetic diversity of T. aestivum/T. timopheevii introgression lines was studied with regard to microsatellite loci and resistance to fungal diseases. Genotyping of hybrid lines and parental common wheat cultivars for 143 SSR markers revealed 521 and 440 alleles, respectively, or 3,24/2,73 alleles per microsatellite locus on the average. Comparison of genetic diversity indices of individual chromosomes revealed the lowest diversity for SSR loci on chromosomes 4D and 5D and the highest (0,62–0,67), on 5B and 6A. Evaluation of SSR polymorphisms and indices H in the three genomes of introgression lines indicated that the chromosomes of genome B had higher rates than A or D (B > A > D) which was probably a result of alien introgression into these chromosomes. Comparison of the results of molecular and phytopathological tests allows us to conclude that despite the severe selection for resistance to leaf rust in early generations and a large number of generations of selfing, the genetic diversity of introgression lines on microsatellite loci is preserved, which is indicative of the stability of alien genetic material in the common wheat genome