LAUSR

Phosphorus (P) deficiency in soil is a major factor that limits barley yield production. Increasing the tolerance to P-deficiency of barley is one of the most cost-effective solutions. Quantitative trait loci (QTLs) controlling P acquisition, P utilization efficiency and biomass at the seedling stage were identified using a population of recombinant inbred lines (RILs) subjected to two P concentrations (low P (LP), 25 µM and normal P (NP), 250 µM). The population was derived from a cross between Baudin and CN4027, which is a Hordeum spontaneum accession. In two hydroponic trials conducted in 2014 and 2016, seventeen QTLs were detected on chromosomes 2H, 3H, 4H and 5H at the two P concentrations. Eight of these QTLs influenced P acquisition efficiency (PAE). Phenotypic variation explained by a particular PAE-related QTL ranged from 13.3 to 39.9%. One QTL designated as Qspue.sau-3H.01 was related to P utilization efficiency (PUE); the phenotypic variation explained by this QTL was 12.5% (NP concentration) and 13.1% (LP concentration), respectively. Strong associations were observed between biomass and P efficiency-related traits in our study. Two QTL clusters controlling biomass, PAE- and PUE-related traits simultaneously were stably identified in the intervals bPb3263664–bPb3931069 and bPb3264570–bPb4786261 on chromosome 3H at both P concentrations in both trials. The QTLs related to PAE, PUE and biomass are important for the P-tolerant phenotype and may offer valuable clues for fine mapping and map-based cloning of barley.