Dissertation Research: The Origins of Polyploid Eragrostis tef (Poaceae): Phylogeny, Genetic Diversity, and Infraspecific Phylogeography

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0098509Doyle and Ingram Tef (Eragrostis tef) is an annual cereal crop grown primarily in Ethiopia whose evolutionary origins within the grass genus Eragrostis are unknown. The proposed research by graduate student Amanda Ingram with guidance from adviser Dr. Jeff Doyle at Cornell University has the primary goal of investigating the evolutionary relationships among previously proposed progenitors of tef to identify extant representatives of the crop's progenitors and to elucidate relationships within this large and poorly investigated genus of grasses. They will be using DNA sequence data from a variety of loci, including low-copy nuclear genes and a chloroplast locus, as sources of characters for the comparative genetic analyses of the likely diploid progenitor taxa and of numerous accessions of polyploid tef (which combines whole sets of chromosomes from different parents). The data from the nuclear genes will help identify both progenitor species, while the chloroplast loci will help identify the maternal progenitor of tef. Additional taxa will also be included in the analysis of these data to begin generating hypotheses of relationships among major lineages in this grass genus, which currently has 350 named species. Another component of this project will be investigating the morphological changes involved in the domestication of tef through comparisons with its wild progenitors. These studies will be useful in helping identify target genes for future investigations into the genetic changes involved in the domestication process. Genetic diversity within tef and its wild relatives will also be examined through the use of highly variable molecular markers. These data will also be helpful in determining the genealogical structure of various tef cultivars, and this may helpidentify the center of domestication and diversity of this important crop, including genetic diversity of possible value in future breeding work.