Molecular Analysis of Bambara Groundnut, an Underutilised African Legume Crop as Part of the Bamlink Project - What Lessons Can We Learn?

Abstract

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.

Root Foraging Capacity in Bambara Groundnut (Vigna Subterranea (L.) Verdc.) Core Parental Lines Depends on the Root System Architecture during the Pre-Flowering Stage

“…In the last 30 years, drought breeding work on bambara groundnut has been limited and largely focused and elucidated by above ground shoot morpho-physiological studies [11,13,14,16,19,[36][37][38][39][40][41][42]. In order to fully understand and better manipulate the ability to tolerate water-limited conditions, the range of both above-and belowground variation present in bambara groundnut germplasm needs to be explored [43].…”

Genetic diversity and population structure of Bambara groundnut (Vigna subterranea (L.) Verdc.): synopsis of the past two decades of analysis and implications for crop improvement programmes

“…Specifically for Bambara groundnut, various molecular analyses of diversity have been reported to either argument or validate the various reports based on phenotypic descriptors (Table 6; Pasquet et al 1999;Massawe et al 2003aMassawe et al , 2002Olukolu et al 2012;Aliyu and Massawe 2013;Mayes et al 2013;Molosiwa et al 2015). The earliest report of diversity analysis at the molecular/cellular level in Bambara groundnut includes the report of Pasquet et al (1999).…”

“…(3) Based on the various reports indicating high allelic diversity, low observed heterozygosity and high inbreeding coefficient, a single landrace could be considered as an 'unselected cultivar/variety' (Molosiwa et al 2015). This could lead to 'short circuiting' of breeding with just few rounds of single seed/plant selection, enough to purify landraces for variety development (Mayes et al 2013;Aliyu et al 2015;Molosiwa et al 2015). This present an opportunity to explore various short to medium term strategies for variety development in breeding programmes ( Fig.…”

“…However, for most underutilized crop species, the lack of availability of large numbers of speciesspecific molecular markers is the main hindrance to applying genomic assisted breeding in their crop improvement programmes (Mayes et al 2011). Specifically for Bambara groundnut, some speciesspecific genomic resources have been reported; 10 SSR markers (Basu et al 2007c), 143 SSR markers (Beena et al 2013), 75 SSR markers (Mayes et al 2013;Molosiwa et al 2015), 201 DArT Array markers (Stadler 2009;Olukolu et al 2012;Molosiwa et al 2015), XSpecies (Affymetrix microarray) (Chai et al 2013). Through the African orphan crop consortium (http://africanorphancrops.org/), efforts are underway for sequencing of Bambara groundnut to produce a genome sequence draft, alongside an effort to re-sequence 100 inbred lines of Bambara groundnut.…”

Exploration of Bambara Groundnut (Vigna subterranea (L.) Verdc.), an Underutilized Crop, to Aid Global Food Security: Varietal Improvement, Genetic Diversity and Processing

“…Generally, the West-Central African genotypes and the South-Eastern African genotypes are always clustered separately throughout the molecular analysis [76]. In Bambara groundnut, studies on comparative genomics analysis between leaf transcriptome in Bambara groundnut and other crop species have been evaluated to enable the detection of suitable cross-species orthologues and the crop model genes [94,97,139]. The outcome revealed that soybean scored a similar maximum similarity transcript sequence to that of Bambara groundnut, and among the other species (Vigna radiate, Riciniscommunis, Populastrichocarpa, Arabidopsis lyrata, Vitisvinifera, and Medicagotruncatula) examined in the study and may be used in the form of a gene model in Bambara groundnut gene expression profiling [97].…”