The use of genetic markers allows the study of polymorphism and genetic distances between maize lines in greater depth than can be achieved on the basis of phenotype and DUS traits. The analysis of polymorphism between 46 maize inbred lines with known genetic background and the classification of these lines in related groups was carried out by means of morphological description, isoenzyme analysis, RAPD analysis, and identification using gene-linked microsatellite (SSR) markers. The genetic distance or degree of relationship between the lines was determined using cluster analysis. Only a very limited extent of allele polymorphism could be detected in isoenzyme analyses; the 46 lines formed only 18 gel electrophoresis groups. Nevertheless, on the basis of RAPD and SSR markers, all the lines could be distinguished from each other. This was reflected by the PIC (polymorphism index content) values, which ranged from 0.04 to 0.55 (mean 0.27) for the various enzyme loci, while far higher values were obtained for RAPD and SSR markers (0.20–0.91, mean 0.61, and 0.54–0.90, mean 0.73, respectively). Due to the large number of lines, two lines, derived from each other or from common parents, were chosen from each related group as the basis for grouping the lines according to genetic background. It was found that, while the individual marker systems only partially reflected the actual relationships between the lines, a joint processing of the genetic markers, supplemented with morphological data, revealed a close correlation between the groups formed on the dendrogram and the genetic background.
Authors:M. Molnár-Láng, G Linc, E. D. Nagy, and et al.
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.