Wheat is one of the most important food crops in the world and understanding its genetics and genome organisation is of great value for genetics and plant breeding purposes. Despite is genome complexity (polyploidy), hexaploid and tetraploid wheats behave as diploids during meiosis. This means that each chromosome only recognises its identical (homologue) to pair and not the related chromosomes (homeologues). There are several pairing homologous (Ph) genes controlling chromosome pairing in wheat during meiosis. The strongest effect is associated with the Ph1 locus, which is located on the long arm on chromosome 5B. Ph1 appears to sense homology prior to the chromosomes coming into contact with each other at early meiosis. Thus, if the chromosomes are true homologues, they perfectly recognise each other, chromatin remodelling is synchronized and allows pairing and recombination to occur. If the chromosomes are homoeologous (related), remodelling is not synchronized and the chromosomes fail to pair and recombine. In the absence of Ph1, all chromosomes can remodel without the requirement for the presence of an identical or near identical chromosome, and this increases the chance of pairing between related chromosomes in addition to pairing between true homologues. In this project we want to analyse deeper this Ph1 behaviour and we also want to exploit ph1 mutants as a tool for wheat breeding programs to promote inter-specific recombination between related wild species. In fact, Hordeum chilense (wild barley with interesting agronomic traits for wheat breeding) introgressions will be developed into durum wheat to transfer desirable agronomic traits from this wild barley into wheat, like resistance to diseases or the increment in carotene content. Introgression lines will be crosses with ph1 mutants to promote inter-specific recombination H. chilense-wheat, reduce the size of the H. chilense chromosome fragment. New wheat varieties will be generated.
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