Developing wheat that acquires and uses phosphorus(P)more efficiently is a promising and low-cost solution for increasing grain yield and reducing P-related environmental impacts.The present study iden-tified agronomic and physiological traits that contribute to genetic variation in the P acquisition,remo-bilization,and utilization efficiency of 11 wheat cultivars from southwest China grown in P-deficient purple lithomorphic soil(Olsen P=4.7)with balanced(75 kg P ha-1)and excess P(120 kg P ha-1)sup-plies.On average,soil P deficiency(-P)reduced root P uptake(17.0％-60.8％),P remobilization(33.9％-52.8％),dry mass yield(11.5％-39.2％),and grain yield(17.7％-54.4％).Balanced P(+P)increased grain yield via increased plant biomass rather than increased HI.-P increased phosphorus uptake efficiency(PUpE,4.5-fold),phosphorus utilization efficiency(PUtE,1.25-fold),and phosphorus use efficiency(PUE,5.4-fold)compared with those under+P,and PUtE explained most(58.1％-60.8％)of the genetic variation in PUE under both-P and+P.The high root P uptake of P-efficient cultivars under-P was regulated by root surface area and root length density in the 0-10 cm soil layer but not in the 10-20 and 20-40 cm soil layers,suggesting that a topsoil foraging strategy is a more economical approach than deeper root exploration for increasing P uptake.Root P uptake before anthesis and P remobilization after anthesis were critical for increasing the PUtE of wheat,given that P-efficient cultivars showed higher Pn(net pho-tosynthetic rate)and sucrose levels than P-inefficient cultivars.Pn reduction by-P resulted from decreased Gs and Ci,and high evapotranspiration under+P increased shoot P％by increasing root P uptake.Genetic variation in the source-to-sink ratio was observed in consequence of a+P-induced allometric increase in sucrose in leaves and kernels.Owing to these beneficial effects,+P increased the kernel N and P yields of the 11 cultivars by 9.9％-52.4％and 12.3％-48.8％,respectively.The findings of this study could help improve wheat in future breeding efforts and P management by identifying desirable P-efficient phenotypes in P-deficient farming systems.

Hongkun Yang;Renhua Chen;Yufeng Chen;Han Li;Ting Wei;Wei Xie;Gaoqiong Fan

Crop Ecophysiology and Cultivation Key Laboratory of Sichuan Province,Sichuan Agricultural University,Chengdu 611130,Sichuan,China;Key Laboratory of Crop Ecophysiology&Farming System in Southwest China,Ministry of Agriculture and Rural Affairs,Chengdu 611130,Sichuan,China;State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China,Ministry of Science and Technology,Chengdu 611130,Sichuan,China

作物学报（英文版）

[1]Hongkun Yang;Renhua Chen;Yufeng Chen;Han Li;Ting Wei;Wei Xie;Gaoqiong Fan-.Agronomic and physiological traits associated with genetic improvement of phosphorus use efficiency of wheat grown in a purple lithomorphic soil)[J].作物学报（英文版）,2022(04):1151-1164

lithomorphic,PUpE,PUtE,under+P,and+P,tosynthetic,a+P

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