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Molecular cytogenetic analysis of wheat-alien hybrids and derivatives

Molnár-Láng, M., Linc, G, D. Nagy, E., et al.,
Acta agronomica Academiae Scientiarum Hungaricae 2002 v.50 no.3 pp. 303-311
Aegilops biuncialis, backcrossing, barley, centromeres, chromosome addition, chromosome pairing, chromosome translocation, colchicine, cultivars, cytogenetic analysis, diploidy, fluorescence, fluorescence in situ hybridization, gene transfer, genetic markers, hybrids, microsatellite repeats, molecular cloning, octaploidy, pollen, rye, tissue culture, triticale, wheat
New wheat × barley, wheat × <i>Aegilops biuncialis</i> 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 <i>in situ</i> hybridization (GISH) in two combinations (Mv9 kr1 × Igri, Asakazekomugi × Manas). <i>In vitro</i> 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-<i>Aegilops biuncialis</i> additions were produced after backcrossing the wheat-<i>Ae. biuncialis</i> amphiploids. Fluorescence <i>in situ</i> hybridization (FISH) was carried out using two repetitive DNA clones (pSc119.2 and pAs1) on <i>Ae. biuncialis</i> 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.