NATIVE MAIZE GENOTYPIC VARIABILITY FOR PHOSPHORUS EFFICIENCY AND RESPONSIVENESS AT THE FLOWERING STAGE

Abstract

Phosphorus (P) deficiency can severely limit maize yield. Efforts to develop cultivars with tolerance to P deficiency represent a solution which is more sustainable than sole reliance on P fertilizer application. This study evaluated genotypic variability in P efficiency and response at the flowering stage of maize (Zea mays L.) accessions from the P'urhépecha Plateau, at Michoacán, México. Twenty-seven accessions were grown on P-deficient andosol, at four locations with low (25 kg P₂O₅ ha^-1) and high (50 kg P₂O₅ ha^-1) P fertilization under rain-fed conditions. The accessions differed greatly in their growth and P efficiency, defined as growth under suboptimal P availability. They were divided into three categories based on P efficiency, and four categories according to P efficiency in combination with high P response. The distribution of accessions among three P efficiency classes was stable across locations. Accessions SHUI-2 (6), ZR-6 (75), Paso del Muerto (113), Tepetate (206) and Macho II-04 (230) had the highest efficiency under low P and also responded to high P fertilization. P-efficient accessions had greater biomass, P tissue content and P acquisition efficiency (PAE) under P deficiency. Late maturity of P efficient genotypes improved PAE and growth under low P. These results indicate that maize landraces from the P'urhépecha Plateau exhibit genotypic variation for P efficiency and P responsiveness.