Construction of a genetic linkage map and QTL analysis in bambara groundnut.

Bambara groundnut (Vigna subterranea (L.) Verdc.) is an indigenous underutilized legume that has the potential to improve food security in semi-arid Africa. So far, there are a lack of reports of controlled breeding populations that could be used for variety development and genetic studies. We report here the construction of the first genetic linkage map of bambara groundnut using a F3 population derived from a "narrow" cross between two domesticated landraces (Tiga Nicuru and DipC) with marked divergence in phenotypic traits. The map consists of 238 DArT array and SSR based markers in 21 linkage groups with a total genetic distance of 608.3 cM. In addition, phenotypic traits were evaluated for a quantitative trait loci (QTL) analysis over two generations. A total of 36 significant QTLs were detected for 19 traits. The phenotypic effect explained by a single QTL ranged from 11.6% to 49.9%. Two stable QTLs were mapped for internode length and growth habit. The identified QTLs could be useful for marker-assisted selection in bambara groundnut breeding programmes.

Beyond landraces: developing improved germplasm resources for underutilized species - a case for Bambara groundnut.

The potential for underutilized crops (also known as minor, neglected or orphan crops) to improve food and nutrition security has been gaining prominence within the research community in recent years. This is due to their significance for diversified agricultural systems which is a necessary component of future agriculture to address food and nutritional security concerns posed by changing climate and a growing world population. Developing workable value chain systems for underutilized crop species, coupled with comparative trait studies with major crops, potentially allows us to identify suitable agricultural modalities for such species. Bambara groundnut (Vigna subterranea L. Verdc.), an underutilized leguminous species, is of interest for its reported high levels of drought tolerance in particular, which contributes to environmental resilience in semi-arid environments. Here, we present a synopsis of suitable strategies for the genetic improvement of Bambara groundnut as a guide to other underutilized crop species. Underutilized crops have often been adapted over thousands of years in particular regions by farmers and largely still exist as landraces with little or no genetic knowledge of key phenotypic traits. Breeding in these species is fundamentally different to breeding in major crops, where significant pedigree structures and history allow highly directed improvement. In this regard, deploying new integrated germplasm development approaches for variety development and genetic analysis, such as multi-parent advance generation inter-crosses (MAGIC), within breeding programmes of underutilized species will be important to be able to fully utilize such crops.