INGRAM, AMANDA L.* AND JEFF J. DOYLE. L. H. Bailey Hortorium, Cornell University, Ithaca, NY 14853. - Polyploid origin of Eragrostis tef: evidence from the waxy locus.
Eragrostis tef (Zucc.) Trotter (Poaceae) is an allotetraploid
cereal crop cultivated primarily in Ethiopia and Eritrea. Of the
approximately 350 species in Eragrostis, a total of thirteen
potential diploid and polyploid progenitors have been proposed to be
the sources of tef's genome, but rigorous tests of these competing
hypotheses have not been performed. We are using sequence data from a
1250 bp region of the waxy locus (granule-bound starch
synthase; GBSSI), a low-copy nuclear gene, to test the hypotheses of
tef's origins. We have amplified 2 partial and 4 complete exons and 5
introns from this locus, and have sampled homoeologous copies of the
gene in the polyploid taxa. Preliminary results from cladistic
analyses of waxy sequences support the widely held notion that
tef is a domesticate of E. pilosa, a widespread and
morphologically similar allotetraploid.
Key words: Eragrostis, Poaceae, polyploid, tef, waxy