LAUSR

The objective of this study was to comprehensively investigate the relationship of phosphorus (P) concentration and accumulation with yield formation and P use efficiency for grain production (PUEg) using 127 rice recombinant inbred lines grown in a working field under low (LP) and high P (HP) conditions. Phosphorus concentration and accumulation, P translocation (PT) and translocation efficiency (PTE), PUEg, P harvest index (PHI), grain yield, and grain yield components were investigated. Wide ranges in grain yield, straw P concentration, total P accumulation, and PUEg were observed under LP and HP conditions. Coefficients of variance showed that the grain P concentration was considerably conserved, whereas the straw P concentration was relatively variable among inbred lines. In comparison with grain P, straw P made a larger contribution to total P accumulation (PUP) at maturity. Growth duration had no substantial effect on PUEg and positively affected P accumulation under both P conditions; however, it negatively affected the grain P concentration under the HP condition. The straw P concentration was negatively correlated with the grain filling percentage and harvest index. PUEg was negatively correlated with the grain and straw P concentrations, suggesting that low P concentrations, especially in straw, favored a high PUEg. There was no correlation between the P concentrations in grain and straw. The correlation analysis indicated that low straw P concentrations might be partly attributed to high PTE and PHI values. These results show that low straw P concentrations may simultaneously improve PUEg and grain yield by enhancing P translocation into grain, thus reducing the need for P fertilizer application.