Identification of a maize (Zea mays L.) inbred line adapted to low‐P conditions via analyses of phosphorus utilization,root acidification,and calcium influx

Phosphorus (P) fertilizers are essential for achieving high crop productivity, but declining soil P reserves and cost of fertilizers suggest that improving crop varieties for improved use efficiency of P be important for sustainability. To explore the possibility of selecting crops suitable for low P conditions, two maize (Zea mays L.) inbred lines, i.e., W22 and W23 were compared for growth, root morphology, and electrophysiological parameters, under hydroponic conditions with either insoluble P source (LP) or soluble P source (HP) in a factorial completely randomized design. Relative shoot biomass of W23 was significantly (38%) greater than that of W22 with LP, while relative root biomass of the two inbred lines did not differ. With LP, the P stress factor was the lowest (25%) and P dissolution in hydroponic solution was the greatest for W23. Root electrophysiological analysis revealed that W23 had 89% greater H⁺ efflux and 225% greater Ca²⁺ influx than W22 with LP. The distant elongation zone (DEZ) of W23 root was significantly longer and more shoot‐ward than W22 with LP. Thus, W23, having significantly greater relative shoot biomass, lower P stress factor, greater P dissolution, greater H⁺ efflux and Ca²⁺ influx, longer and more shoot‐ward DEZ, was better adapted to low‐P condition compared to W22. In the future, the W23 inbred line can be used for developing low‐P stress resistant varieties to utilize native insoluble soil P efficiently or to produce commercially acceptable yields using lower rates of soluble P fertilizers.