An approach to detecting quantitative trait loci and candidate genes associated with salinity tolerance in faba bean (Vicia faba)

Faba bean is one of the most important high protein cool-season grain legumes, but it is sensitive to salinity stress. Improved salt tolerance of faba bean is needed to increase its yield and area of production. In this study, a recombinant inbred line (RIL) population, derived from the bi-parental cross of 'Icarus' × 'Ascot', was phenotyped under control and saline treatments. Quantitative trait locus (QTL) analysis of this population detected multiple QTL for leaf ionic concentration (Na+, K+ and Cl−) under both treatments. Of these, seven QTL were detected under salt treatment, including three for leaf K+:Na+ (qK:Na-S-1, qK:Na-S-2 and qK:Na-S-3) and one each for Na+ accumulation (qNa-S), K+ accumulation (qK-S), Cl− accumulation (qCl-S) and Na+:K+ (qNa:K-S). An important region was identified on linkage group I.A/III/V, which contained three co-located QTL (qNa-S, qCl-S and qK:Na-S-3) for leaf Na+, Cl− and K+:Na+ accumulation. Potential candidate genes within these QTL intervals were shortlisted using the Medicago truncatula genome. These findings are expected to facilitate the breeding of new salt tolerant faba bean cultivars. KEYWORDS chloride, faba bean, potassium, quantitative trait locus, salinity, sodium