Genetic linkage map construction and identification of QTLs associated with agronomic traits in bambara groundnut (Vigna subterranea (L.) Verdc.) using DArTseq‐based SNP markers

Abstract

Bambara groundnut [Vigna subterranea (L.) Verdc.] is an underutilised, protein‐rich and self‐pollinating legume that can withstand high temperature and drought stress and is mainly grown in semi‐arid Africa. In order to dissect the complexity of drought resistance and to use genomic tools for yield enhancement of bambara groundnut in response to drought stress, yield‐related and morphological traits under drought‐stressed (DS) and well‐watered (WW) conditions were evaluated in the F3 and F4 segregating generations derived from a cross between two genotypes selected from landraces S19‐3 (originally from Namibia) and DodR (originally from Tanzania). Significant quantitative trait loci (QTLs) for shoot dry weight (SDW) were mapped on LG10 accounting for 15.5% of the phenotypic variation explanation (PVE) under well‐watered conditions and a putative quantitative trait locus (QTL) for the same trait mapped on LG10 with reduced PVE (10.10%) under drought‐stressed conditions in the F3 segregating population. Significant QTLs associated with the number of seeds per plant (NS), number of double‐seeded pods per plant (NDP), seed weight per plant (SW) and pod weight per plant (PW) were mapped on LG4 (nearest marker: 4181663 and 4175954) with overlapping confidence intervals and explained 21.9%, 21.8%, 23.5% and 19.9% of the PVE, respectively, under well‐watered conditions in the F4 population, which could be considered as the major QTL involved in the control of these traits. Seven consensus QTLs for yield‐related and morphological traits were mapped on LG2, LG3, LG4, LG7A and LG10. The study provides fundamental knowledge of QTLs associated with yield‐related and morphological traits under drought‐stressed and well‐watered conditions in bambara groundnut, which is also essential for yield improvement of bambara groundnut in response to drought stress.

Deciphering the molecular basis for photosynthetic parameters in Bambara groundnut (Vigna subterranea L. Verdc) under drought stress

“…Significant QTL associated with F V /F M 4 under well-watered conditions was mapped on LG3 with 36.5% of the PVE, while putative QTL for F V /F M 4 was mapped on LG7A with reduced PVE (27.2 of the PVE) under drought-stressed conditions in the F 4 population. Similar to gs5 , a reduced PVE was detected under drought-stressed conditions compared to well-watered conditions, suggesting the traits identified under well-watered conditions were unable to fully express their potential trait values under drought conditions [ 22 ].…”

“…Keyvan [ 35 ] reported wheat cultivars with high RWC under drought stress conditions to be resistant. The putative QTL for RWC3 and seeds weight per plant under well-watered conditions were mapped on LG6A with overlapping confidence intervals, suggesting RWC and seed yield may be controlled by the same gene [ 22 ]. Further validation of consensus markers, significant QTLs associated with various traits and candidate genes is required in different populations, across locations and seasons in bambara groudnnut.…”

“…Kendabie et al [ 21 ] reported that five segregating population, i.e., Ankpa4 × IITA-686 (reciprocal), Ankpa4 × DodR, Ankpa4 × DipC, S19-3 × Ankpa4 and IITA-686 × LunT were developed to create genetic linkage map and enhance trait dissection in bambara groundnut to accelerate crop breeding process. A genetic linkage map covering 1,040.92 cM across 11 linkage groups was constructed using 234 DArTseq-based SNP markers in the F 2 segregating population from S19-3 × DodR [ 22 ]. Significant QTLs associated with number of seeds per plant, number of double-seeded pod per plant, seed weight per plant and pod weight per plant were mapped on LG4 with overlapping confidence intervals under well-watered conditions in the F 4 population, which could be considered as major QTL involved in the control of these traits [ 22 ].…”

“…A genetic linkage map covering 1,040.92 cM across 11 linkage groups was constructed using 234 DArTseq-based SNP markers in the F 2 segregating population from S19-3 × DodR [ 22 ]. Significant QTLs associated with number of seeds per plant, number of double-seeded pod per plant, seed weight per plant and pod weight per plant were mapped on LG4 with overlapping confidence intervals under well-watered conditions in the F 4 population, which could be considered as major QTL involved in the control of these traits [ 22 ]. QTLs associated with stomatal density, length and conductance were co-located on chromosome II under greenhouse conditions in faba bean ( Vicia faba L.) [ 23 ].…”

Orphan crops: A genetic treasure trove for hunting stress tolerance genes

“…Subsequently, independent studies followed the characterization of orphan crops by utilization of genetic resource developed through AOCC. For example, Gao et al (2021) crossed two landraces of Bambara groundnut, S19‐3 (from Namibia) and DodR (from Tanzania), and screened the F3 generation to identify QTLs associated with yield‐related traits under well‐watered and water‐deficit conditions. The QTLs expressed under well‐watered condition were associated with number of seeds per plant, number of pods per plant, and pod weight per plant, whereas QTL associated with internode length was expressed under water‐stressed condition.…”