A study of the mechanisms of meiosis in wheat

Breeding programs have the objectives to develop more productive and more stable varieties. Hybridization and selection are frequently employed in plant breeding and the success of introgression of special traits such as disease resistance relies on genetic recombination between the host and alien chromosomes. During meiosis, homologous chromosomes recognized each other, align and pair which ensure their recombination and correct segregation at metaphase. This process controls aberrant chromosome number within the gametes, and ensures that genes are shuffled by recombination. 70% of flowering plants are polyploids including bread (hexaploid) and pasta wheat (tetraploid), and strict homologous pairing in species containing more than one genome is even more important. Wheat homologous chromosomes and their relative homoeologues are genetically close enough to pair during meiosis, however, the Ph1 locus ensures that only true homologues pair and recombine, stabilizing the wheat genome. Because the pairing is exclusive to homologues, alien chromosomes cannot recombine with wheat chromosome and are eliminated. Deletion lines for the Ph1 locus, allowing recombination of wheat and its relatives, are used for new wheat variety production.EThOS - Electronic Theses Online ServiceGBUnited Kingdo