Genetic diversity in African yam bean accessions based on AFLP markers: towards a platform for germplasm improvement and utilization

Abstract

Accurate knowledge of intra-specific diversity of underutilized crop species is a prerequisite for their genetic improvement and utilization. The diversity of 77 accessions of African yam bean (AYB, Sphenostylis stenocarpa) was assessed by amplified fragment length polymorphism (AFLP) markers. A total of EcoRI/MseI primer pairs were selected and 227 AFLP bands were generated, of which 59(26%) were found to be polymorphic in the 77 accessions of AYB. The most efficient primer combination for polymorphic detection was E-ACT/M-CAG with a polymorphic efficiency of 85.5%, while the least efficient was E-AGC/M-CAG with a polymorphic efficiency of 80.6%. The Jaccard genetic distance among the accessions of AYB ranged between 0.048 and 0.842 with a mean of 0.444. TSs98 and TSs104B were found to be the most similar accessions with a genetic similarity of 0.952. The neighbour-joining dendrogram grouped the 77 accessions of AYB into four distinct clusters comprising 8, 20, 21 and 28 accessions. The major clustering of the accessions was not related to their geographical origin. Cluster I was found to be the most diverse. The mean fixation index (0.203) and the mean expected heterozygosity (0.284) revealed a broad genetic base of the AYB accessions. The same germplasm set was previously evaluated for several agro-morphological traits. As the collection of additional AYB germplasm continues, the phenotypic profile, the clustering of the accessions and the AFLP primer combinations from this study can be used to augment breeding programmes.

Analysis of genetic diversity of African yam bean using SSR markers derived from cowpea

“…In the work carried out by Ojuderie et al (2014), the Bangladesh accession grouped together with the two accessions of Ghana origin. Moreover, the clustering of accessions in the present research was not on the basis of geographical origins and this concur with previous reports (Moyib et al , 2008; Adewale et al , 2014). This result seems to suggest high exchange of AYB germplasm among smallholder farmers across regions.…”

“…The research conducted by Moyib et al (2008) using RAPDs revealed considerable genetic diversity among 24 AYB accessions. Furthermore, AFLPs analysis presented a high level of diversity among AYB accessions (Adewale et al , 2014; Ojuederie et al , 2014).…”

“…Unfortunately, despite the crop's acknowledged potential, it is still classified as neglected and underutilized species (Padulosi et al , 2013); and little information at the molecular level is available. DNA-based markers previously used in this species include random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphisms (AFLPs) (Moyib et al , 2008; Adewale et al , 2014; Ojuederie et al , 2014); however, there is no report on the use of simple sequence repeat (SSR) primers. SSRs being co-dominant in nature, abundant in genomes and highly polymorphic are markers of choice for crop improvement especially for crops like AYB where single nucleotide polymorphisms are yet to be identified.…”

Perennial Staple Crops: Yields, Distribution, and Nutrition in the Global Food System

“…Interestingly, it is chiefly grown as an annual, but has received some attention as a perennial component in annual intercropping systems in place of the non-food producing leguminous trees (like Leucaena) typically used in arid alley cropping (Daniel and Ong, 1990;Waldman et al, 2017). The African yam bean (Sphenostylis stenocarpa Harms) is an interesting crop in that it is grown for both its beans (which can be harvested perennially), and its large edible tuber (thus ending its life); this underutilized crop is being studied for traits and genetic markers to assist in breeding (Adewale et al, 2012(Adewale et al, , 2015. Finally, the protein category also includes alfalfa (Medicago sativa) and stinging nettle (Urtica dioica) for their leaf protein concentrate (LPC), a tofu-like product created by deriving protein-rich curds from leaf juice or pulp.…”

Role of Plant Genetic Resources in Food Security

“…A number of underutilised crops have significant potential, particularly within systems where their nitrogen fixation abilities can play a major role in enhancing soil fertility for other crops. For example, African yam bean is a leguminous crop which is considered to have considerable unrealised potential to contribute to food security in many parts of sub-Saharan Africa (Adewale et al, 2015). However, as with many 'orphan' crops there is a lack of good data about current production and usage.…”