In recent years 56 accessions of Triticum timopheevii Zhuk. (2n=4x=28, AtAtGG) were characterized for the main phenotypic and resistance characters. Among these accessions 38 originated from the base species together with subspecies and varietas forms thereof, and 18 belong to the subspecies armeniacum group. After the evaluation of field assessment data gathered over 12 years, the most promising 11 accessions were selected for a crossability trial with cultivated einkorn. As a result of this trial, the accession with the highest seed set (Acc. No.: MVGB845) was chosen for the development of a new synthetic amphiploid using the same semi-dwarf line of diploid cultivated einkorn (Triticum monococcum L. ssp. monococcum 1T-1, 2n=2x=14, AmAm) as in the crossability trial. This einkorn line was bred in Martonvásár, and has both outstanding resistance and other promising phenotypic and agronomic characters.After crossing the accession MVGB845 with 1T-1, the triploid hybrids were treated with colchicine to obtain fertile progenies with a doubled genome. The newly developed synthetic hexaploid wheat breeding stock (named Triticum timococcum Kost., 2n=6x=42, AtAtGGAmAm) could ease the introgression of valuable resistance genes into bread wheat at the hexaploid level (bridge-crossing).The aim of the present research was to redevelop Triticum timococcum based on a detailed characterization of gene bank accessions, and to introduce this new material into wheat breeding.
Triticum monococcum represents an important source of useful genes and alleles that it would be desirable to use in wheat breeding programmes. The well-defined landmarks on the Am chromosomes could accelerate the targeted introgression of T. monococcum chromatin into the wheat genome.Fluorescence in situ hybridization (FISH) using the repetitive DNA probes pSc119.2, Afa family and pTa71 showed that the pSc119.2 probe was not suitable for the identification of Am chromosomes. In contrast, the whole set of Am chromosomes (especially chromosomes 1, 4, 5 and 7) could be discriminated based on the hybridization pattern of pTa71 and Afa family. In situ hybridization with microsatellite motifs (GAA, CAG, AAC and AGG) proved that SSRs represent additional landmarks for the identification of Am chromosomes. The most promising SSR probes were the GAA and CAG motifs, which clearly discriminated the 6Am chromosome and, when used in combination with the Afa family and pTa71 probes, allowed the whole set of Am chromosomes to be reliably identified.In conclusion, fluorescence in situ hybridization using the repetitive DNA probes Afa family and pTa71, combined with SSR probes, makes it possible to identify the Am chromosomes of T. monococcum and to discriminate them from Au chromosomes in the polyploid wheat background.
New wheat × barley, wheat × Aegilops biuncialis and wheat × rye hybrids were produced with the aim of alien gene transfer from these species into wheat. Amphiploids were produced with the help of colchicine treatment from the last two combinations. The new wheat × barley hybrids were multiplied in tissue culture because of the high degree of sterility and then pollinated with wheat to obtain backcross progenies. Wheat-barley chromosome pairing was detected using genomic in situ hybridization (GISH) in two combinations (Mv9 kr1 × Igri, Asakazekomugi × Manas). In vitro conditions caused an increase in chromosome arm association frequency in both combinations and in fertility in some regenerants. Five wheat-barley translocations were produced in a wheat background and characterized through the combination of cytogenetic and molecular genetic approaches (GISH, FISH and SSR markers). The following translocations were identified: 2DS.2DL-1HS, 3HS.3BL, 6BS.6BL-4HL, 4D-5HS and 7DL.7DS-5HS. Physical mapping of the SSR markers on chromosomes 1H and 5H was carried out using the intragenomic and interspecific translocation breakpoints and the centromere as physical landmarks. Disomic wheat-Aegilops biuncialis additions were produced after backcrossing the wheat-Ae. biuncialis amphiploids. Fluorescence in situ hybridization (FISH) was carried out using two repetitive DNA clones (pSc119.2 and pAs1) on Ae. biuncialis and its two diploid progenitor species to detect chromosome polymorphism. The 7M and 3M disomic chromosome additions were selected and five more lines still need to be characterized. The octoploid triticale (Mv9 kr1 × Lovászpatonai) produced in Martonvásár was crossed with a 1RS.1BL wheat cultivar Matador. GISH analysis detected pairing between the 1RS arm of the translocation chromosome and that of Lovászpatonai rye in 32 % of the pollen mother cells, making it possible to select recombinants from this combination. The new recombinants between the 1RS of Petkus and the 1RS of Lovászpatonai rye cultivars are being analysed with the help of microsatellite markers.
Acta Agronomica Hungarica, 48(3), pp. 227–236 (2000) OCCURRENCE OF THE 1RS/1BL WHEAT–RYE TRANSLOCATION IN HUNGARIAN WHEAT VARIETIES B. K Ő SZEGI, G. LINC, A. JUHÁSZ, L. LÁNG and M. MOLNÁR-LÁNG AGRICULTURAL RESEARCH INSTITUTE OF THE HUNGARIAN ACADEMY OF SCIENCES, MARTONVÁSÁR, HUNGARY Received: August 15, 2000; accepted: October 15, 2000 The translocation which involves the substitution of the short arm of the 1R rye chromosome for the short arm of the 1B wheat chromosome by means of centric fusion has exercised an enormous influence on the world’s wheat breeding. Since the first mention of this translocation in 1937 the incidence of the 1RS/1BL translocation has been reported in connection with several hundred wheat varieties. Varieties carrying the translocation possess a chromosome segment which includes the resistance genes Sr31 (stem rust, Puccinia graminis), Lr26 (leaf rust, P. recondita), Yr9 (yellow rust, P. striiformis), Pm8 (powdery mildew, Erysiphe graminis) and Gb (aphid, Schizaphis graminum). The present paper investigates the occurrence of the 1RS/1BL translocation in wheat varieties bred in Hungary in recent years. It was found that 35 (53%) of the 66 Hungarian-bred wheat varieties registered in Hungary between 1978 and 1999 carried the 1RS/1BL translocation.
The aim of the experiments was to develop translocation lines by inducing homoeologous chromosome pairing in a 4H(4D) wheat-barley substitution line previously developed in Martonvásár. It was hoped to incorporate various segments of the barley 4H chromosome from the 4H(4D) substitution into wheat. Observations were made on the frequency with which wheat-barley translocations appeared in the F
progeny grains from a cross between the line CO4-1, which carries the
suppressor gene from
and thus induces a high level of homoeologous chromosome pairing, and the 4H(4D) wheat-barley substitution line, and on which chromosome segments were involved in the translocations. The translocations were identified by means of genomic
hybridisation. Of the 117 plants examined, three (2.4 %) were found to contain translocations. A total of four translocations were observed, as one plant contained two different translocations. The translocations consisted of one centric fusion, two dicentric translocations and one acrocentric chromosome. Plants carrying translocations were raised in the phytotron and the selection of homozygous translocation lines was commenced from the F
The 4H(4D) wheat/barley substitution line was crossed with the ‘Chinese Spring’ ph1b mutant genotype in order to induce wheat-barley homoeologous recombinations. F3 and F4 seeds of the 4H(4D) × ‘Chinese Spring’ ph1b mutant cross were analysed using genomic in situ hybridization, and a Robertsonian translocation was detected in monosomic form. Disomic centric fusions were selected among the self-fertilized progenies. The presence of the long arm of 4H was confirmed with SSR markers. The long arm of the 5D wheat chromosome in the Robertsonian translocation was identified using fluorescent in situ hybridization with the help of three DNA probes: pSc119.2, Afa family and pTa71. The wheat/barley centric fusion was identified as a 4HL.5DL translocation. This line exhibited supernumerary spikelet character, but the number of seeds/plant did not increase. The 4HL.5DL centric fusion line is suitable genetic material to study the expression of genes located on 4HL in a wheat genetic background.