Plant & Animal Genomes XIV Conference Plant & Animal Genomes XIV ConferenceJanuary 14-18, 2006
Town & Country Convention Center
San Diego, CA
Shavannor M. Smith1 , Yinan Yuan2 , Jeffrey L. Bennetzen1
Eragrostis tef (Zucc.), a member of the chloridoideae subfamily of grasses, is one of the most important food crops in Ethiopia, constituting ~30% of the acreage devoted to cereal crops. Lodging is the most important production problem in tef, resulting in grain losses of up to 50% in some areas. Currently, there are no tef varieties available with lodging resistance comparable to improved maize, wheat or rice varieties. The rht1 and sd1 dwarfing genes have been useful for improving lodging resistance in wheat and rice, respectively. We have cloned and sequenced the rht1 and sd1 orthologues from tef. Tef carries two putative rht1 homologues, likely representing separate (“homoeologous”) copies of this locus in the allotetraploid tef genome. Sequence variation between homoeologoues will allow calculation of the approximate ancestral divergence dates for these two genomes within tef. Three putative sd1 orthologues were identified in tef. We have cloned and sequenced these five genes from 31 tef accessions collected from various regions in Ethiopia. The sequence diversity of these accessions was organized into a relatively small number of haplotypes for rht1 and sd1, ranging from ten haplotypes for one rht1 homologue to two haplotypes for an sd1 homologue. An overall low level of nucleotide diversity was observed at all loci. Linkage disequilibrium (LD) analysis of the 5 loci demonstrated strong LD extending the length of the gene investigated (2-4 kb), with no significant decline. There was no dramatic correlation between haplotypes of any of these genes and their site of origin.