Gish reveals different levels of meiotic pairing with wheat for individual aegilops biuncialis chromosomes

Abstract

The Triticum aestivum Aegilops biuncialis (2n=4x=28; UbUbMbMb) disomic addition lines 2Mb, 3Mb, 7Mb and 3Ub were crossed with the wheat cv. Chinese Spring ph1b mutant genotype in order to induce homoeologous pairing, with the final goal of introgressing Ae. biuncialis chromatin into cultivated wheat. Wheat-Aegilops homoeologous chromosome pairing was studied in metaphase I of meiosis in the F1 hybrid lines. Using U and M genomic probes, genomic in situ hybridization (GISH) demonstrated the occurrence of wheat-Aegilops homoeologous pairing in the case of chromosomes 2Mb, 3Mb and 3Ub, but not in the case of 7Mb. The wheat-Aegilops pairing frequency decreased in the following order: 2Mb > 3Mb > 3Ub> 7Mb, which may reflect differences in the wheat-Aegilops homoeologous relationships between the examined Aegilops chromosomes. The selection of wheat-Aegilops homoeologous recombinations could be successful in later generations.