Detection of QTLs for phosphorus use efficiency in relation to agronomic performance of wheat grown under phosphorus sufficient and limited conditions

The objective of this study was to map QTLs regulating P uptake (PUP) and utilization efficiency (UTE), and analyze the association of these QTLs with agronomic traits of wheat under low P (LP) and high P (HP) conditions. Two consecutive field trials harvested at maturity and two independent pot trials harvested at seedling stage were conducted using a doubled haploid (DH) population derived from two Chinese winter wheat varieties, Hanxuan 10 and Lumai 14. Characteristics including tillers per plant (TN), shoot dry weight, PUP and UTE were investigated in the two pot trials, while PUP, UTE, biomass yield and yield components were investigated in the two field trials. Seven and six loci were detected repeatedly as controlling PUP and UTE, respectively. Each of the seven PUP loci coincided with or was linked to QTLs regulating agronomic traits, thus providing strong evidence for the hypothesis that enhancing PUP would improve agronomic performance of wheat, especially under LP condition when insufficient PUP retarded plant development. Although PUP and UTE were negatively correlated, positive linkages were observed between QTLs for PUP and UTE at two loci, allowing for the possibility of improving PUP and UTE simultaneously. Various loci controlling TN and PUP at the seedling stage were found to regulate ear number per plant, biomass yield and PUP at maturity, suggesting that selection of early vigorous plants with more tillers and higher PUP would improve PUP and plant performance at maturity.