Plant & Animal Genomes XVI Conference

January 12-16, 2008
Town & Country Convention Center
San Diego, CA

Quantitative Trait Loci (QTL) Mapping Of Protein Content In Backcross Derivatives Of Inter-Specific Hybrids From M. esculenta Sub spp.Flabellifolia And Cassava (Manihot esculenta Crantz)

Olalekan Akinbo^1,2 , Martin Fregene² , Maryke Labuschagne¹

  ¹Department of Plant Science, University of the Free State, Bloemfontein 9300, Republic of South Africa

  ²Centro Internacional de Agricultura Tropical (CIAT), Cali, Colombia

The domestication process of cassava has led to a decrease in genetic variability compared to wild progenitors. Traits, for example high protein content of storage roots (>18% on a dry weight basis), have been found in M. esculenta sub spp flabellifolia, a progenitor of cassava. The enriched protein trait was recovered in F1 inter-specific hybrids with a range of 5 – 12% on a dry weight basis, typical levels in cassava are 2%. A modified Advanced Backcross QTL (ABC-QTL) mapping program was initiated to increase the efficiency of transferring the trait into cassava. Plant material for QTL mapping was 227 BC1 genotype derived from crossing an inter-specific hybrid of M. esculenta sub spp flabellifolia with high protein content (11%) and cassava. A total of 817 SSR markers were screened between parental genotypes of the BC1 population and 40% of the markers were polymorphic and used to genotype the entire population. The high protein content trait was evaluated in a replicated field trial and measured as total nitrogen in dry root flour obtained from 8months old plants. QTLs controlling protein in the root was putatively identified using the first year phenotypic data. The BC1 populations are being evaluated for a second year to determine QTL x genotype effects. Selected BC1 progenies with high protein content and QTLs associated with high protein content will be crossed to elite cassava parental lines to continue the process of transfer of the high protein trait into cassava gene pools.