Mapping QTLs for aluminium and phosphorus tolerances at seedling and reproductive stages in lentil (Lens culinaris Medikus)

• Two contrasting parents (BM-4 and L-4602) were utilized to develop recombinant inbred lines for mapping Al and P tolerances QTLs. • A total of 7 QTLs associated with aluminium and phosphorus tolerances using composite interval mapping (CIM). • Four major QTLs, qAlt _ rrg, qAlt_fs, qAlt2.1, qAltP1.1 were identified for root re-growth, flourescent signals, aluminium and phosphorus contents with PVEs of 18.2%, 10.2%, 19.8% and 18.9%, respectively. • These quantitative trait loci might prove to be very beneficial in the marker-assisted breeding of lentil that is resilient to Al and P stress conditions. Aluminium toxicity and phosphorus deficiency are primary limitations to crop yield under acidic soil conditions. Developing aluminium (Al) and phosphorous (P) stress tolerant cultivars is one of the effective way to increase plant productivity under acidic soils. Hence, the present study was conducted at 6 different acidic environments during 2020-21 and 2021-22 to map quantitative trait loci (QTLs) associated with Al and low P tolerances in 150 F 7 recombinant inbred lines derived from BM-4 (Al-sensitive) x L-4602 (Al-tolerant) genotypes. Sixteen morpho-physiological and yield related traits were studied in response to Al and P stresses under hydroponic and field conditions. Seven QTLs were identified using composite interval mapping on linkage group 1 for six morpho-physiological traits including root re-growth (RRG), fluorescent signals (callose accumulation), aluminium content, phosphorus content, days to flowering and days to maturity under Al stress (E-1), Al with P stresses (E-2) and acidic field condition (E-6). Individual QTLs accounted for logarithm of odd (LOD) values of 2.73 to 6.85 and phenotypic variation between 5.4% to 19.8%. The major QTLs with Al tolerance and P efficiency components can be integrated into elite lentil cultivars using molecular breeding. Improved lentil lines for Al tolerance and P efficiency will reduce the input need for lime application and phosphate fertilizers, significantly cutting costs, together with increased productivity in acidic, and P deficient soils, altogether boosting farmers’ and seed industry profitability.