Genotyping of hexaploid wheat varieties from different Russian regions

We used molecular-genetic and molecular-cytology approaches to characterize the genomes of 20 varieties of wheat created in different regions of Russia. A molecular-genetic analysis was performed using 29 SSR-markers covering the entire genome, and 41 ISBP-markers localized on chromosome 5B. Analysis of genetic similarity based on the results of molecular genotyping showed that the winter wheat varieties form a common cluster, regardless of the origin or area of cultivation. This is primarily due to the fact that the varieties originating from the European part of Russia were used to establish winter wheat varieties for West Siberia. Comparative analysis of individual dendrograms constructed using 1–2 markers per chromosome, and with the involvement of a larger number of 5B-chromosome markers allowed us to identify varieties with rearrangements of this chromosome and to assess genetic diversity. We found that winter wheat Vassa and spring wheat Chelyaba 75 were clustered closely together. This is an indirect confirmation of the use of winter wheat varieties in the breeding to improve the productive potential of spring wheat. Molecular-cytology analysis by C-banding and fluorescence in situ hybridization (FISH) revealed various chromosomal rearrangements in 8 of 20 cultivars studied, including translocations from S. cereale, Ae. speltoides and Th. intermedium. Thus, a combination of the two approaches allowed us to better characterize genomes of wheat varieties of various origin

Alien introgressions and chromosomal rearrangements do not affect the activity of gliadin-coding genes in hybrid lines of Triticum aestivum L. × Aegilops columnaris Zhuk

Using chromosome C-banding and electrophoresis of grain storage proteins, gliadins, 17 Triticum aestivumAegilops columnaris lines with substitutions of chromosomes of homoeologous groups 1 and 6 were examined. Based on their high polymorphism, gliadins were used to identify alien genetic material. For all of the lines examined, electrophoretic analysis of gliadin spectra confirmed substitution of wheat chromosomes 6A, 6D or 1D for the homoeologous Aegilops chromosomes of genomes Uс or Xс. The substitution manifested in the disappearance of the products of gliadin-coding genes on chromosomes 6A, 6D or 1D with the simultaneous appearance of the products of genes localized on alien chromosomes of genomes Uс or Xс. Thus, Aegilops chromosomes were shown to be functionally active in the alien wheat genome. The absence of alien genes expression in the lines carrying a long arm deletion in chromosome 6Xc suggested that the gliadin-coding locus moved from the short chromosome arm (its characteristic position in all known wheat species) to the long one. This is probably associated with a large species-specific pericentric inversion. In spite of losing a part of its long arm and combination with a non-homologous chromosome of a different genome (4BL), chromosome 1D was fully functioning. For Aegilops, the block type of gliadin components inheritance was shown, indicating similarity in the structural organization of gliadin-coding loci in these genera. Based on determining genetic control of various polypeptides in the electrophoretic aegilops spectrum, markers to identify Ae. columnaris chromosomes 1Xс, 6Xс and 6Uс were constructed

Study of resistance to leaf and stem rusts in Triticum aestivum–Aegilops speltoides lines

Presently, the use of bread wheat introgression lines resistant to pathogens in practical breeding is hampered by the lack of their cytogenetic characteristics, data on the genetic control of disease resistance, and influence of alien genetic material on grain productivity and quality. For the solution of these problems, two wheat–Aegilops speltoides lines, L195 and L200, developed at ARISER and resistant to leaf and stem rusts were studied. These lines were produced by crossing of spring bread wheat cultivars to line L26b-4. Cytogenetic analysis of the lines involved C-banding, meiotic analyses, and FISH with pAs1 and Fat. It allowed the rust resistance genes, efficient against both rust types, to be mapped to a 2D-2S translocation in both lines. Genetic analysis revealed tight linkage of leaf rust resistance genes from Ae. speltoides to gametocidal genes and absence of susceptible plants from the F2 hybrids and subsequent generations. Exceptions were found only in hybrid combinations with lines L2032 and L583: occasional susceptible plants were noted  in the F2 and subsequent generations. Evaluation of lines L195 and L200 revealed high resistance to Ug99 + Lr24 (TTKST) and a local Saratov population of stem rust. The prebreeding studies of lines L195 and L200 showed their benefits in breeding for grain productivity in comparison with the recipient cultivar L503 and good bread-making quality. Due to the complex of agronomical traits and high resistance to leaf and stem rusts, lines L195 and L200 can be considered promising donors for commercial bread wheat breeding

Cytomolecular identification of individual wheat-wheat chromosome arm associations in wheat-rye hybrids

Chromosome pairing in the meiotic metaphase I of wheatrye hybrids has been characterized by sequential genomic and fluorescent in situ hybridization allowing not only the discrimination of wheat and rye chromosomes, but also the identification of the individual wheat and rye chromosome arms involved in the chromosome associations. The majority of associations (93.8%) were observed between the wheat chromosomes. The largest number of wheat-wheat chromosome associations (53%) was detected between the A and D genomes, while the frequency of B-D and A-B associations was significantly lower (32 and 8%, respectively). Among the A-D chromosome associations, pairing between the 3AL and 3DL arms was observed with the highest frequency, while the most frequent of all the chromosome associations (0.113/ cell) was found to be the 3DS-3BS. Differences in the pairing frequency of the individual chromosome arms of wheat-rye hybrids have been discussed in relation to the homoeologous relationships between the constituent genomes of hexaploid wheat

The study of genetic factors that determine the awned glume trait in bread wheat

Awns are bristle‐like structures, typically extending from the tip end of the lemmas in the florets of cereal species, including such economically important crops as wheat (Triticum aestivum L., T. durum Desf.), barley (Hordeum vulgare L.), rice (Oryza sativa L.), and rye (Secale cereale L.). The presence of long awns adhered at tip end of glumes is a characteristic feature of “Persian wheat” T. carthlicum Nevski spike. Glume outgrowth of T. carthlicum Nevski spike passes into a long awn, equal in length to the lemma awn. Awned glumes can be formed in T. aestivum and T. aethiopicum wheats, however, such forms are rare. Features of the awned glume development and the genetic determinants of this trait have been little studied. In this paper, we described the features of the development and inheritance of the tetra-awness (awned glume) trait of the bread wheat T. aestivum line CD 1167-8, using classical genetic analysis, molecular genetic mapping, and scanning electron microscopy. It was shown that the trait is inherited as a recessive monogenic. The gene for the awned glume trait of CD 1167-8 was mapped in the long arm of chromosome 5A, using the Illumina Infinium 15K Wheat Array (TraitGenetics GmbH), containing 15,000 SNPs associated with wheat genes. Results of allelism test and molecular-genetic mapping suggest that the gene for awned glumes in bread wheat is a recessive allele of the B1 awn suppressor. This new allele was designated the b1.ag (b1. awned glume). Analysis of the CD 1167-8 inflorescence development, using scanning electron microscopy, showed that awns had grown from the top of the lemmas and glumes simultaneously, and no differences in patterns of their development were found

Development of the genetic classification of Aegilops columnaris Zhuk. chromosomes based on the analysis of introgression lines Triticum aestivum×Ae. columnaris

Aegilops columnaris Zhuk. is a potential source of new genes for wheat improvement. However, this species has not yet been used in practical breeding. In the present work we have for the first time reported the development and molecular-cytogenetic characterization of T. aestivum×Ae. columnaris introgression lines. Analysis has not revealed alien genetic material in five of the 20 lines we have studied, while the remaining lines carried from 1 to 3 pairs of Aegilops chromosomes as addition(s) or substitution(s) to wheat chromosomes. Altogether, five different chromosomes of Aegilops columnaris have been detected in the karyotypes of 15 lines by C-banding and fluorescent in-situ hybridization (FISH). Based on substitution spectra, these chromosomes were identified as 3Ае1, 3Ае2, 5Ае2, 6Ае1 and 6Ае2. In addition, another Aegilops chromosome has been found in the line 2305/1 as a monosomic addition; due to the lack of group-specific markers we were unable to assign this chromosome to a particular genome or a genetic group and therefore it was designated Ае-а. In several lines acrocentric and telocentric chromosomes have been revealed (Ae-b and Ae-c). It is most likely that these chromosomes were derived from unknown Aegilops chromosomes due to a large deletion. A comparison of electrophoretic spectra of gliadins in introgression lines L-2310/1 and L-2304/1 with substitutions of chromosome 6D with two different chromosomes of Ae. columnaris (these lines were assigned to the 6th homoeologous group based on C-banding data) has shown that they carry different alleles of the gliadin loci. This observation confirmed that lines L-2310/1 and L-2304/1 contained non-identical 6Ae chromosomes. Taking into consideration our previous results of FISH analyses, three other Ae. columnaris chromosomes can be assigned to homoeologous groups 1, 5 and 7 of the U-genome based on the location of 5S and 45S rDNA loci (1U and 5U) or pSc119.2 probe distribution (7U). Thus, based on our current data as well as on the results of earlier work, we can identify eight out of the 14 chromosomes of Aegilops columnaris

A study of bread wheat lines from crosses with the synthetic form Avrodes in regard to their yellow rust resistance

The genome-substituted synthetic form Avrodes (AABBSS) was used for transferring resistance to yellow rust (Puccinia striiformis f. sp. tritici Eriks.) from Aegilops speltoides Tausch, (2n = 14) to bread wheat. The study involved 24 introgressive lines of bread wheat obtained using the Avrodes form. Yellow rust resistant lines P07-L.02, P07-L.1, P07-L.17, P07-L.43, P07-L.19, AS12-88, AS12-06, AS12-07, AS12- 51, Asp81-21, Asp63-21, Asp053-21, Asp04-21, Asp022-19, Asp023-19 and Asp029-20 were selected and can be used as new donors of disease resistance. The use of differential chromosome staining (C-banding) and fluorescence in situ hybridization (FISH) identified the genetic material of Ae. speltoides transmitted in the form of 5S(5D) chromosome substitution and translocations of T5BS.5BL-5SL, T2DL.2DS-2SS, T5D, as well as translocation of T1BL.1RS from Secale cereale L. The work revealed that the lines with single translocations of T1BL.1RS and T5BS.5BL-5SL were susceptible to yellow rust, while the lines in which the T2DL.2DS-2SS translocation and 5S(5D) substitutions were identified, as well as the lines with translocations of T1BL.1RS, T2DL.2DS-2SS and T5D showed resistance to the disease. Presumably, the selected introgression lines, obtained by means of crosses with Avrodes, may carry new genes or loci for yellow rust resistance

Use of a synthetic form Avrodes for transfer of leaf rust resistance from Aegilops speltoides to common wheat

Diploid wild relative of wheat – Aegilops speltoides – is a valuable source of genes for resistance to diseases. The synthetic form Avrodes (BBAASS) was used as a bridge to transfer leaf rust resistance genes from Ae. speltoides to common wheat. Introgression lines obtained from crosses of Avrodes and susceptible common wheat cultivars were evaluated in a field leaf rust nursery. Resistance levels varied from high to moderate. Testing of lines with the use of molecular markers has shown that some lines have the Lr28 and Lr35 genes inherited from synthetic form Avrodes. The majority of resistance lines have not been found to carry these genes. The Lr47 and Lr51 genes were not identified in the Avrodes and introgression lines. The analysis of chromosome pairing in F1 hybrids showed that the transfer of a genetic material from Avrodes to common wheat basically occurs through translocations. Lines with translocations on chromosomes 2D and 5D were identified by C-banding and FISH. The translocations differed in chromosomal location from known leaf resistance genes transferred to common wheat from Ae. speltoides. Hence it was assumed that new genes were introduced into the common wheat genome from Ae. speltoides. Introgression lines have been studied for productivity and technological qualities of grain. Lines AA60n9 and D37n10 combine high resistance to leaf rust with good characteristics of productivity and technological qualities of grain. The received results demonstrate a genetic diversity and a value of the investigated introgression lines for breeding of common wheat

Using the synthetic form RS5 to obtain new introgressive lines of common wheat

The use of the gene pool of wild relatives, which have a significant reserve of genetic diversity, is of immediate interest for breeding common wheat. The creation and use of synthetic forms as “bridges” is an effective method of transferring valuable genetic material from wild relatives to cultivated wheat. For this purpose, genome addition, genome substitution and recombinant “secondary” synthetic forms have been created in the P.P. Lukyanenko National Center of Grain. The synthetic recombination form RS5 (BBAASDt ), in which the third genome consists of chromosomes of Aegilops speltoides (S) and Aegilops tauschii (Dt ), was obtained from crossing the synthetic forms Avrodes (BBAASS) and M.it./Ae. tauschii (BBAADt Dt ), in which the D genome from Ae. tauschii was added to the BBAA genomes of the durum wheat cultivar Mutico italicum. Introgression lines resistant to leaf rust, yellow rust and powdery mildew have been obtained from backcrosses with the susceptible common wheat cultivars Krasnodarskaya 99, Rostislav and Zhirovka. Twelve resistant lines that additionally have high technological characteristics of grain and flour have been selected. The cytological study (С-banding) has revealed chromosomal modifications in 6 of 8 lines under study. The rearrangements mainly affected the chromosomes of the D genome, 1D, 3D, 4D, 6D and 7D. It was found that in most cases the genetic material from the synthetic form RS5 in the studied lines was represented by substituted chromosomes from Ae. tauschii. In line 5791p17, the substitution of chromosomes 6D from Ae. tauschii and 7D from Ae. speltoides was revealed. Substitutions 4D(4Dt ), 6D(6Dt ) from Ae. tauschii and 7D(7S) from Ae. speltoides were obtained for the first time. Molecular analysis of 12 lines did not reveal effective leaf rust resistance genes, presumably present in synthetic forms of M.it./Ae. tauschii and Avrodes. It is assumed that the lines may carry previously unidentified genes for fungal disease resistance, in particular for resistance to leaf rust, from Ae. tauschii and Ae. speltoides

The development and study of common wheat introgression lines derived from the synthetic form RS7

Synthetic recombination form RS7 (BBAAUS), in which the first two genomes, A and B, originate from common wheat, and the third recombinant genome consists of Aegilops speltoides (S) and Ae. umbellulata (U) chromosomes, was obtained from crossing synthetic forms Avrodes (BBAASS) and Avrolata (BBAAUU). Resistant to leaf rust, yellow rust and powdery mildew, introgression lines have been obtained from backcrosses with the susceptible varieties of common wheat Krasnodarskaya 99, Fisht and Rostislav. PCR analysis showed the presence of amplification fragments with marker SCS421 specific for the Lr28 gene in the line 4991n17. The cytological study (С-banding and FISH) of 14 lines has revealed chromosomal modifications in 12 of them. In most cases, the lines carry translocations from Ae. speltoides, which were identified in chromosomes 1D, 2D, 3D, 2B, 4B, 5B and 7B. Also, lines with the substituted chromosomes 1S (1B), 4D (4S), 5D (5S) and 7D (7S) were identified. Lines that have genetic material from Ae. speltoides and Ae umbellulata at once were revealed. In the line 3379n14, translocations in the short arm of chromosome 7D from Ae. umbellulata and chromosomes 5BL, 1DL, 2DL from Ae. speltoides were revealed. The line 4626p16 presumably has a translocation on the long arm of chromosome 2D from Ae. umbellulata and the T7SS.7SL-7DL translocation from Ae. speltoides. The T1DS.1DL-1SL and T3DS.3DL-3SL translocations from Ae. speltoides, and T2DS.2DL-2UL and T7DL.7DS-7US from Ae. umbellulata have been obtained for the first time. These lines may carry previously unidentified disease resistance genes and, in particular, leaf rust resistance genes from Ae. speltoides and Ae. umbellulata