Meiotic pairing in a trigeneric hybrid Triticum tauschii Agropyron cristatum Hordeum chilense

The chromosome affinity among the P genome from Agropyron and the D and H-c h genomes of Triticum and Hordeum in the absence of the Pit system controll ing homoeologous chromosome pairing provides information for breeding purpo ses. Hybrids between two accesions of the diploid barley Hordeum chilense ( (HHch)-H-ch) and the fertile amphiploid Triticum tauschii-Agropyron cristat um (DDPP) were made, giving rise to the trigeneric hybrid genomic combinati ons (HDP)-D-ch from which such information could be obtained. The meiotic p airing of these hybrids using fluorescence genomic in situ hybridization (F ISH) on metaphase I pollen mother cells yield data on allosyndetic and auto syndetic chromosome pairing between the three genomes. The results showed t hat the A. cristatum tetraploid parent of the amphiploid DDPP is a segmenta l alloploid. A higher pairing between the D and H-ch genomes than between t hem and the P genome from A. cristatum is observed.