Exploiting genetic variability in maize for phosphorus (P) efficiency is one of the viable strategies to turn around the element deficiency in tropical and subtropical regions. In order to verify differences among maize genotypes on phosphorus utilization and grain yield, two experiments were conduted. First, eighteen corn genotypes (ten local varieties, six improved varieties, and two hybrids) were evaluated in two soil P levels (10 and 100 mg.kg -1 de P), under greenhouse conditions. The second experiment, five local varieties and one improved variety, and one hybrid were evaluated under field conditions at crescent levels of P fertilization (0; 8.7; 17.5; 35; 70, and 140 kg.ha -1 de P). Genetic variability was detected for P efficiency at greenhouse conditions. The local varieties (Argentino, Amarelão, Caiano de Sobrália, Asteca, Quarentão and Caiano de Alegre), the improved ones (BR 106 and BR 107), and the hybrid P 6875 were the genotypes with the highest efficiency indexes. Under field conditions, the effects of P addition in grain production and P content in the grains were observed. The genotypes exhibited different levels in response to increased nutrient availability. The local varieties Cravinho and Carioca, and the hybrid P 6875 were the most responsive, besides presenting the highest grain yield in the absence of P fertilization. Nitroflint (improved variety) and Catetão (local variety) presented the lower response to P addition and the lower grain yield without P addition.
phosphorus nutrition; genetic variability; local varieties; Zea mays
