A Cross between Bread Wheat and a 2D(2R) Disomic Substitution Triticale Line Leads to the Formation of a Novel Disomic Addition Line and Provides Information of the Role of Rye Secalins on Breadmaking Characteristics

A bread wheat line (N11) and a disomic 2D(2R) substitution triticale line were crossed and backrossed four times. At each step electrophoretic selection for the seeds that possessed, simultaneously, the complete set of high molecular weight glutenin subunits of N11 and the two high molecular weight secalins of rye, present in the 2D(2R) line, was carried out. Molecular cytogenetic analyses of the BC4F8 generation revealed that the selection carried out produced a disomic addition line (2n = 44). The pair of additional chromosomes consisted of the long arm of chromosome 1R (1RL) from rye fused with the satellite body of the wheat chromosome 6B. Rheological analyses revealed that the dough obtained by the new addition line had higher quality characteristics when compared with the two parents. The role of the two additional high molecular weight secalins, present in the disomic addition line, in influencing improved dough characteristics is discussed.

A Cross between Bread Wheat and a 2D(2R) Disomic Substitution Triticale Line Leads to the Formation of a Novel Disomic Addition Line and Provides Information of the Role of Rye Secalins on Breadmaking Characteristics

A bread wheat line (N11) and a disomic 2D(2R) substitution triticale line have been crossed and backrossed four times. At each step electrophoretic selection for the seeds that possessed, simultaneously, the complete set of high molecular weight glutenin subunits of N11 and the two high molecular weight secalins of rye, present in the 2D(2R) line, was carried out. Molecular cytogenetic analyses of the BC4F5 generation have revealed that the selection carried out had produced a disomic addition line (2n=44). The pair of additional chromosomes consisted of the long arm of chromosome 1R (1RL) from rye fused with the satellite body of the wheat chromosome 6B. Rheological analyses revealed that the dough obtained by the new addition line had higher quality characteristics when compared with the two parents. The role of the two additional high molecular weight secalins, present in the disomic addition line, in influencing improved dough characteristics is discussed.

The consensus rye microsatellite map with EST-SSRs transferred from wheat

Microsatellite (SSR) markers with known precise intrachromosomal locations are widely used for mapping genes in rye and for the investigation of wheat-rye translocation lines and triticale highly demanded for mapping economically important genes and QTL-analysis. One of the sources of novel SSR markers in rye are microsatellites transferable from the wheat genome. Broadening the list of available SSRs in rye mapped to chromosomes is still needed, since some rye chromosome maps still have just a few microsatellite loci mapped. The goal of the current study was to integrate wheat EST-SSRs into the existing rye genetic maps and to construct a consensus rye microsatellite map. Four rye mapping populations (P87/P105, N6/N2, N7/N2 and N7/N6) were tested with CFE (EST-SSRs) primers. A total of 23 Xcfe loci were mapped on rye chromosomes: Xcfe023, -136 and -266 on chromosome 1R, Xcfe006, -067, -175 and -187 on 2R, Xcfe029 and -282 on 3R, Xcfe004, -100, -152, -224 and -260 on 4R, Xcfe037, -208 and -270 on 5R, Xcfe124, -159 and -277 on 6R, Xcfe010, -143 and -228 on 7R. With the exception of Xcfe159 and Xcfe224, all the Xcfe loci mapped were found in orthologous positions considering multiple evolutionary translocations in the rye genome relative to those of common wheat. The consensus map was constructed using mapping data from the four bi-parental populations. It contains a total of 123 microsatellites, 12 SNPs, 118 RFLPs and 2 isozyme loci.

Participation of Wheat and Rye Genome in Drought Induced Senescence in Winter Triticale (X Triticosecale Wittm.)

The aim of the study was to identify the regions of triticale genome responsible for senescence under drought induced during the generative stage. We performed quantitative analysis of chlorophylls (a and b), carotenoids, soluble carbohydrates, and phenolic compounds. QTL (Quantitative Trait Loci) calculations were based on a previously developed and characterized genetic map involving 92 lines of doubled haploid derived from F1 hybrid ‘Hewo’ × ‘Magnat’ and two DH parental lines (‘Hewo’ and ‘Magnat’). We identified seven QTLs, including four on chromosome 2A, one on chromosome 1R, and two on chromosome 6R. Only three loci, QSPh.2A.1, QSC.2A.2 and QSC.2A.4 mapped single traits, i.e., the content of soluble phenolics and carbohydrates. Single QTL (QCSPh.1R) was responsible for changes in the levels of chlorophyll a and b, carotenoids and soluble phenolics. The remaining three loci, QCSPhC.2A.3, QCSPhC.6R.1 and QCSPhC.6R.2 controlled changes in the entire set of investigated traits. We also identified candidate genes for the investigated traits. The loci on chromosome 2A encoded proteins responsible for oligosaccharide transportation and mechanical properties of xylem and the genes regulating carbohydrate metabolism. The chromosomes 1R and 6R contained functional genes possibly associated with carbohydrate and phenolic metabolism.

Mapping of resistance genes to brown rust in 1R chromosome of rye (Secale cereale L.)

Five resistance genes to single-pustule isolates Nos. 12, 81,108 and 7 of brown rust were mapped on 1R chromosome of rye using two different F₂ populations. Under segregation analysis it was found linkage between genes controlling resistance to single-pustule isolates No. 12, 81, 108 and 25 and isozyme locus Prx7, which to be localized on chromosome 1R. The recombination frequencies are 0.32, 0.28, 0.29 and 0.32 correspondingly. Also we were found linkage between Prx7 and gene, controlling resistance to single-pustule isolate No. 7. Recombination frequency in this case was equal 0.10 and 0.29 in dependence on analyzing hybrids.

Characterization of wheat – Secale africanum introgression lines reveals evolutionary aspects of chromosome 1R in rye

Wild Secale species, Secale africanum Stapf., serve as a valuable source for increasing the diversity of cultivated rye (Secale cereale L.) and provide novel genes for wheat improvement. New wheat – S. africanum chromosome 1Rafr addition, 1Rafr(1D) substitution, 1BL.1RafrS and 1DS.1RafrL translocation, and 1RafrL monotelocentric addition lines were identified by chromosome banding and in situ hybridization. Disease resistance screening revealed that chromosome 1RafrS carries resistance gene(s) to new stripe rust races. Twenty-nine molecular markers were localized on S. africanum chromosome 1Rafr by the wheat – S. africanum introgression lines. Twenty markers can also identically amplify other reported wheat – S. cereale chromosome 1R derivative lines, indicating that there is high conservation between the wild and cultivated Secale chromosome 1R. Nine markers displayed polymorphic amplification between S. africanum and S. cereale chromosome 1Rafr derivatives. The comparison of the nucleotide sequences of these polymorphic markers suggested that gene duplication and sequence divergence may have occurred among Secale species during its evolution and domestication.