Deployment of innovative molecular-marker aided techniques requires fundamental resources such as whole genome sequences, genetic maps, and predicative markers associated with desirable traits. Early efforts to develop linkage maps and to identify QTLs used first generation molecular markers such as RAPD and AFLP (Mignouna et al., 2003; Mignouna et al., 2002a; Mignouna et al., 2002b) were developed but the utility in marker-aided breeding has been limited. More recently, EST sequences were developed from a bi-parental populations segregating for anthracnose disease, which led to the discovery of 1152 EST-SSRs (Narina et al. 2011).
However, utilization of the EST-SSR is at initial phase. The latest endeavor in developing yam genomic resources is being undertaken by a joint project by IITA-IBRC-JIRCAS aimed at developing whole genome sequencing of Guinea yam and their relatives using Illumina GAIIx and HiSEQ DNA sequencers. While the assembly of the draft genome is near completion, the daunting task of gene annotation and post-genome resource development is the next crucial step.
In parallel with the de novo genome sequencing, the collaborative project has resequenced 10 Guinea yam genotypes for discovery of SNPs. In addition, the de novo sequencing of the parental genotypes for anthracnose disease (D. alata) has been completed and the progenies are being genotyped using GBS in a collaborative USAID-Linkage project with USDA-ARS, Stoneville and CUGI, Clemson to develop additional genomic resources.
IITA yam breeding has been developing multi-traits bi parental populations of both water and white yam. Multiparent (half –sib) populations have also been developed for white yam. These populations combine yield, shape, multiple tubers, YMV resistance, tuber flesh, dry matter content, oxidation, cooking quality, tuber earliness, and storability, high zinc and iron content. For water yam, populations combine anthracnose and viruses’ resistance, tuber quality after cooking, yield, shape and aerial bulbil production. Read More…