Rationale, implementation and priorities
Why the four legumes?
Groundnut, cowpea, bean and chickpea are essential staples in the diets of millions of Africans, and increasing their yields could greatly improve health and wealth creation in sub-Saharan Africa (SSA). Grain and forage legumes account for 27% of the world's primary crop production, with grain legumes alone contributing 33% of the dietary protein nitrogen needs of humans (Vance et al. 2000). Follow the links below for a few facts and figures on each legume and sub-Saharan Africa:
How will project objectives be achieved?
The molecular breeding approach
The TLI project promotes the application of modern breeding, which combines conventional field breeding with plant biotechnologies, to improve the productivity of four legume crops in SSA. Molecular breeding (MB) is the generic term used to describe several modern breeding strategies including: Marker-assisted selection (MAS) – the selection of specific alleles for traits conditioned by a few loci; marker-assisted backcrossing (MABC) – the transfer of a limited number of loci from one genetic background to another; and, more recently, marker-assisted recurrent selection (MARS) – the identification and selection of several genomic regions involved in the expression of complex traits within a single population.
The effectiveness of MB for simple traits such as some disease resistances as well as for complex traits such
as tolerance to low temperature or drought has been reported in cereals (Ribaut and Ragot 2006), and in commercial crops like soybeans, where many disease resistance traits – including soybean cyst nematode which is typically hard to score phenotypically – are routinely screened with markers (Eathington et al, 2007). MB combined with conventional phenotypic selection is now widely practised by the private sector, but less so by the public sector (Dwivedi et al. 2007). The progress observed in both the private and public sectors suggests that efficient plant breeding through combining phenotypic selection (which considers genetic effects as a whole) with molecular breeding (which allows selection of favourable alleles at target loci) offers great promise for developing country agriculture. Until recently, MB demanded heavy investment in laboratory infrastructure, a limitation that can now be overcome through outsourcing to access the latest technologies. In addition, advances in Single nucleotide polymorphism (SNP) technology are a quantum leap in decreasing marker costs, making this approach extremely cost-effective.