Phosphorus acquisition and internal utilization efficiency among maize landraces from the central Mexican highlands

In many low input maize production systems phosphorus (P) is in limited supply. Improved crops that acquire and use P more efficiently are a sustainable solution to increase crop yield in these systems. This study determined the contribution of P acquisition efficiency (PAE) and P utilization efficiency (PUTE) in determining P use efficiency (PUE) of 20 maize accessions from the Purhepecha Plateau, Michoacan, grown on a P-deficient Andisol, at two locations with low (23 kg P2O5 ha−1) and high (97 kg P2O5 ha−1) P fertilization under rain-fed conditions. Under P deficiency conditions in the acid soil, both PAE and PUTE were important factors explaining the variation in P use efficiency at both P levels. Greater P use efficiency was related to an improved distribution of dry matter in the plants and a lower absorbed P allocated in the grain. Low grain P concentrations at maturity were not associated with reductions in grain yield, nor were they significantly correlated to HI, suggesting that exploiting genotypic variation for this trait may be productive. The study identified genetic variation among maize landraces in their response of PUTE. On a P-deficient acidic soil, accessions CB-2, DP × Tromba, HV313 × DEM, Macho III-04, and CIMMYT-1, were categorized as the most P efficient and the most responsive to increased P availability. In contrast, late maturing P-efficient accessions SHUI-2, CB-2, AS-4, and ZR-6 showed the greatest variation for P uptake under low P conditions. Late maturity improved growth and yield in low P soils. These accessions expressed the desired traits for PUE, which may be exploited in breeding efforts.