Two rye genome-specific random amplified polymorphic DNA (RAPD) markers were identified for detection of rye introgression in wheat. Both markers were amplified in all of the tested materials that contained rye chromatin such as rye, hexaploid triticale, wheat-rye addition lines, and wheat varieties with 1BL.1RS translocation. Two cloned markers, designated pSc10C and pSc20H, were 1012 bp and 1494 bp, respectively. Sequence analysis showed that both pSc10C and pSc20H fragments were related to retrotransposons, ubiquitously distributed in plant genomes. Using fluorescence in situ hybridization (FISH), probe pSc10C was shown to hybridize predominantly to the pericentromeric regions of all rye chromosomes, whereas probe pSc20H was dispersed throughout the rye genome except at telomeric regions and nucleolar organizing regions. The FISH patterns showed that the two markers should be useful to select or track all wheat-rye translocation lines derived from the whole arms of rye chromosomes, as well as to characterize the positions of the translocation breakpoints generated in the proximal and distal regions of rye arms.

The 1BL.1RS translocations between wheat ( Triticum aestivum L.) and rye ( Secale cereale L.) are widely used in bread wheat breeding programs, but all modern wheat cultivars with the 1BL.1RS have shown genetic vulnerability due to one rye source - a German cultivar, Petkus. We have developed, a new 1BL.1RS wheat-rye translocation line from the backcross of the F(1) hybrid of wheat cv. Olmil and rye cv. Paldanghomil, both cultivars from Korea. The GISH technique was applied to identify the presence of rye chromatin in 467 BC(1)F(6) lines selected from 77 BC(1)F(5) lines. Only one line, Yw62-11, showed wheat-rye translocated chromosomes, with a somatic chromosome number of 2n=42. C-banding patterns revealed that the translocated chromosome was 1BL.1RS, showing prominent bands in the terminal and sub-terminal regions of the short arm as well as in the centromeric region and terminal region of the long arm. This new 1BL.1RS translocation line formed 21 bivalents like common wheat at meiotic metaphase I, thereby showing complete homology.

S. 1987. Production and cytogenetic analysis of hybrids between Triticum aestivum and some caespitose Agropyron species. Genome, 29: 537-553. Intergeneric hybrids between Triticum aestivum L. cultivars and 12 traditional Agropyron species were produced in variable frequencies, lowest being 0.35% for A. stipaefolium to a high of 41.98% for A. varnense. The crossing success of T. aestivum cultivars ranged from 'Chinese Spring' > 'Pavon-76' = 'Nacozari-75' > 'Fielder' = 'Fremont' > 'Glennson-81'. All FI hybrids were somatically stable. The new combinations were with A. curvifolium (Thinopyrum curvifolium), A. rechingeri (T. sartorii = rechingeri) , A. scythicum (T. scythicum), and A. stipaefolium (Pseudoroegeneria stipaefolia). All hybrids were perennial and possessed a modified phenotype that was intermediate between the parents involved in the hybrid combinations with major variation in spike morphology (elongated spikes with lax internodes). High-pairing hybrids, presumably owing to suppression of the Ph locus were of T. aestivum -A. scythicum (15.3 1 I + 2.25 I1 rings + 6.92 I1 rods + 0.32 111) and T. aestivum -A. stipaefolium (10.6 I + 7.08 I1 rings + 4.41 I1 rods + 0.54 111). In the other combinations, the pairing was either low or high, and if high, pairing was attributed to autosyndetic association of the alien genome chromosomes. Based on the meiotic pairing data, alien species that were segmental allotetraploids or partial autopolyploids, or segmental allohexaploids or autoallohexaploids, may be advantageous in developing backcross derivatives with synthetic genomes. Production of fertile amphiploids was restricted to T. aestivum -A. rechingeri. ., et FAROOQ, S. 1987. Production and cytogenetic analysis of hybrids between Triticum aestivum and some caespitose Agropyron species. Genome, 29 : 537-553. Des hybrides intergknkriques entre des cultivars de Triticum aestivum L. et 12 especes communes d'Agropyron ont kt6 produits en frkquences variables, depuis les plus basses avec 0,35% pour A. stipaefolium vers les plus hautes avec 41,98% pour A. varnense. Le succes des croisements des cultivars de T. aestivum a Cvoluk comme suit: 'Chinese Spring' > 'Pavon 76' = 'Nacozari 75' > 'Fielder' = 'Fremont' > 'Glenson 81 '. Tous les hybrides F, ont kt6 stables sur le plan somatique. De nouvelles combinaisons ont kt6 faites avec A. curvifolium (Thinopyrum curvifolium), A. rechingeri (T. sartorii = rechingeri), A. scythicum (T. scyticum) et A. stipaefolium (Pseudoroegeneria stipaefolia). Tous les hybrides se sont avkrks vivaces et posskdaient un phknotype intermkdiaire entre les parents impliquks dans les combinaisons hybrides, mais avec une variation majeure dans la morphologie de l'kpi, soit des kpis allongks avec des entrenoeuds inkgaux. Les hybrides dont les appariements furent klevks, prksumkment en raison de la suppression du locus Ph, ont kt6 ceux de T. aestivum -A. scythicum (1 5,3 1 I + 2,25 I1 (en anneaux) + 6,92 11 (en bitonnets + 0,32) et de T. aestivum -A. stipaefolium (10,6 I + 7,08 I1 (en anneaux) + 4,41 I...

Intergeneric hybrids between Triticum aestivum L. and conventional rhizomatous Agropyron species were produced in variable frequencies. They were recovered in high percentage frequencies for T. aestivum cultivars with A. acutum (14.6%), A. intermedium (48.0%), A. pulcherrimum (53.3%), and A. trichophorum (46.6%). The crossability percentages with the highly crossable cultivar 'Chinese Spring' for these Agropyron species accessions were 33.12%, 65.0%, 53.3%, and 65.4%, respectively. Autosyndetic associations of two of their three genomes gave mean meiotic chromosome association data of 17.0 I (univalents) +1.53 II (ring bivalents) + 7.04 II (rod bivalents) +1.43 III (trivalents) +0.05 IV (quadrivalents) +0.01 IV (pentavalents) for A. acutum and of 21.8 I + 1.56 II (rings) +7.22 II (rods) +0.84 III + 0.04 IV for A. intermedium. Chromosome pairing at metaphase I was comparatively lower for A. pulcherrimum (34.4 I + 0.2 II (rings) +3.4 II (rods) +0.14 III) and A. trichophorum (36.7 I + 0.35 II (rings) +2.26 II (rods) + 0.04 III) hybrids with T. aestivum. Hybrids of wheat with A. campestre and A. repens were obtained in low frequency. Direct crossing did not permit T. aestivum/ A. desertorum hybridization. However, by utilizing the 2n=10x=70 A. repens/A. desertorum amphiploid as the pollen source, hybridization with T. aestivum did indeed occur. Aneuploidy was prevalent in this hybrid combination while all other hybrid combinations were apparently normal.