Analysis of Chromosome Associations during Early Meiosis in Wheat Lines Carrying Chromosome Introgressions from Agropyron cristatum

Abstract

Crested wheatgrass (Agropyron cristatum L. Gaertn., genome P), included in the Triticeae tribe (family Poaceae), is one of the most important grasses in temperate regions. It has been valued as a donor of important agronomic traits for wheat improvement, including tolerance to cold, drought, and high salinity, as well as resistance to leaf rust, stripe rust, and powdery mildew. For successful incorporation of beneficial alleles into wheat, it is essential that recombination between wheat and A. cristatum chromosomes occurs. In this work, we analysed chromosome associations during meiosis in wheat lines carrying chromosome introgressions from A. cristatum chromosomes 5P and 6P in the presence and absence of Ph1 locus using fluorescence in situ hybridisation. The results showed that the Ph1 locus does not affect chromosome associations between A. cristatum and wheat chromosomes because there were no interspecific chromosome associations; therefore, no recombination between chromosomes from wheat and Agropyron were observed in the absence of the Ph1 locus. The 5P and 6P A. cristatum chromosomes do not have a suppressor effect on the Ph1 locus. Wheat univalents in metaphase I suggest that Agropyron chromosomes might carry genes having a role in wheat homologous chromosome associations. Putative effect of the Agropyron genes on wheat chromosome associations does not interact with the Ph1 locus.