PHOSPHORUS-USE EFFICIENCY BY CORN GENOTYPES

Phosphorus (P) deficiency is a principal yield-limiting factor for ann ual crop production in acid soils of temperate as well as tropical reg ions. The objective of this study was to screen nine corn (Zea mays L. ) genotypes at low (0 mg P kg(-1)), medium (75 mg P kg(-1)), and high (150 mg P kg(-1)) levels of P applied in an Oxisol. Plant height, root length, shoot dry weight, root dry weight, shoot-root ratio, P concen tration in shoot and root, P uptake in root and shoot, and P-use effic iency parameters were significantly (P<0.01) influenced by P treatment s. Significant genotype differences were found in plant height, shoot and root dry weight, P uptake in root and shoot, and P-use efficiency. Based on dry matter production and P-use efficiency, genotypes were c lassified as efficient and responsive, efficient and nonresponsive, no nefficient and responsive, and nonefficient and nonresponsive.