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.

A total of 170 bambara groundnut (Vigna subterranea) accessions were evaluated using both simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers generated using genotyping-by-sequencing (GbS), of which 56 accessions were collected from West and East Java. Principal coordinate analysis (PCoA), population structure, and cluster analysis suggest that the East Java accessions could be a result of the introduction of selected West Java accessions. In addition, the current Indonesian accessions were likely introduced from Southern Africa, which would have produced a very marked founding effect such that these accessions present only a fraction of the genetic variability that exists within this species.

Bambara groundnut (Vigna subterranea L. Verdc.) is an underutilised, drought tolerant legume that has the potential to form an important part of Food Security for the coming decades. The challenges facing farmers to produce enough food for the growing world population -particularly that of climatic instability -are well documented and together represent probably one of the biggest challenges humanity has faced. Our extreme reliance on a limited number of staple (often nonindigenous and sometimes also poorly adapted) crops represents a clear vulnerability. This can be partly reduced by the development of alternative crops. These currently underutilised crops often have beneficial characteristics not found in conventional main crops and if these traits address either biotic or abiotic stresses in a sustainable way, then there is the potential for agricultural diversification. There are a number of stumbling blocks to developing such crops, including; poor yields, unadapted crop features, limited processing knowledge, few value-added products, poorly developed transport chains and markets, negative cultural perceptions and little perceived profit margin for commercial breeders. An integrated approach is needed to begin to address these problems. As part of this, we have focused on the application of molecular genetics to Bambara groundnut and the opportunities to exploit knowledge from other species, new technologies and new approaches, to establish a framework for genetic improvement through breeding. We also try to draw out lessons from our work in Bambara groundnut which may be relevant in other underutilised species, to try to contribute to the development of a generic approach (and hopefully, a faster and cheaper approach) to tackling these same questions in other underutilised species. In this paper we ask what is the fundamental information we need about the breeding system of an underutilised species and how could this alter our genetic improvement, using Bambara groundnut as an example.

Bambara groundnut has been planted in Indonesia for hundreds of years. Researchers have evaluated where the Indonesian Bambara groundnut landraces were introduced from but no-one has evaluated the stability and adaptability of Bambara groundnut in Indonesia. Thirty-six landraces were planted in Indonesia, together with putative Indonesian × African hybrids and their offspring. These were assessed for their stability and adaptability by the methods of Finlay and Wilkinson (1963) and Eberhart and Russel (1985). Results from seven landraces are presented. The seven landraces were: 'LunT' from Sierra Leone; 'AHM753'; 'SB165A' and 'S19-3' from Namibia; 'DODR' from Tanzania; 'Uniswa Red' from Swaziland; 'DIPC' from Botswana; and the Indonesian landrace 'Gresik' as control. Thirty plants of each landrace were planted in a randomised block design with three replicates at Gresik, Bojonegoro and Jatikerto in Indonesia in November 2009. Each location had a different altitude, soil type and rainfall. Gresik is the main Bambara groundnut growing region in the East of Java, Indonesia. Prior to this experiment, farmers in Bojonogoro and Jatikerto were not familiar with this crop. Many traits were assessed based on the list of descriptors of Bambara groundnut issued by IPGRI, but in this report we present only the results of stability and adaptability analysis for 50% flowering, days to maturity, pod number per plant and the 100 seeds weight traits. Analysis of variance showed highly significant differences in all three locations and combined analysis of variance over sites (Gomez and Gomez, 1983) indicated that location, landraces and location × landraces interaction are substantially different (1%). Stability and adaptability parameters were obtained as the linear regression coefficient (bi) of the mean of all data observed and deviation from the regression analysis (S 2 di) with the hypothesis that bi=1 and S 2 di =0. The results indicated that almost all landraces observed were stable, but only three landraces revealed good adaptability in all three locations, namely 'SB165A', 'Uniswa Red' and 'DIPC'. Meanwhile 'LunT' and 'S19-3' are considered promising landraces because they are well adapted in two of the four variables used. This information could prove useful for breeding programmes.