Genetic diversity of a Bambara groundnut germplasm representing accessions from 25 African countries, maintained at the International Institute of Tropical Agriculture (IITA; Nigeria) was evaluated based on seed patterns, qualitative characters, quantitative traits and Diversity Arrays Technique (DArT) markers. The study aimed at identifying important descriptors for germplasm conservation, validating the crop's geographical centre of origin and facilitating the utilization of existing genetic resources. Frequencies and diversity indices of seven types of seed patterns, 12 qualitative and 28 quantitative traits were evaluated for 124 representative accessions and were analyzed by region to elucidate the geographic distribution of descriptor states. In addition, individual plant samples from a subset of 40 landrace accessions were analyzed by assessing 554 DArT markers. Both the phenetic tree constructed from the qualitative and quantitative descriptors and the population structure derived from DArT marker analysis suggested a relatively high genetic diversity among accessions. Higher genetic diversity was observed for the Cameroon/Nigeria region relative to other regions, in agreement with the hypothesis that this region is the centre of origin for Bambara groundnut. Use of an extensive and diverse range of germplasm and an approach that integrated morphological and quantitative descriptors with DNA markers that represent wide genomic coverage offered a powerful way to make inferences about crop germplasm, in support of crop-improvement programs.

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Prohexadione-Ca is a structural mimic of 2-oxoglutarate, and according to this property, it is able to inhibit dioxygenase enzymes, which require 2-oxoglutarate as a cosubstrate. Such enzymes are involved in flavonoid biosynthesis; therefore, prohexadione-Ca treatment leads to alterations in the flavonoid metabolism in grapevine tissues. Because of the fact that phenolic compounds often are responsible for enhanced plant resistance, modification of phenylpropanoid metabolism using elicitation can be considered as a new potential strategy in plant protection. The phenolic compounds were analyzed by high-performance liquid chromatography combined with chemical reaction detection. Tissue treatment induced the accumulation of unusual flavonoids, which were identified as derivatives of pentahydroxyflavanone, eriodictyol, and luteoliflavan. Concentrations of constitutive flavonoids were also affected by the bioregulator treatment. The alterations of the flavonoid profiles are discussed with respect to substrate preferences of relevant enzymes.

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.