Relação entre caracteres determinantes da eficiência no uso de nitrogênio e fósforo em milho

• Autor(a) principal: Pereira, Felipe Bermudez
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4751
• topic: Milho; Nitrogênio; Fósforo; Relação; Maize; Nitrogen; Phosphorus; Relation; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::PASTAGEM E FORRAGICULTURA::MELHORAMENTO DE PLANTAS FORRAGEIRAS E PRODUCAO DE SEMENTES

The efficiency in the use of N (EUN) and P (EUP) in maize is important because it allows achieving satisfactory yields with lower costs and in a sustainable way. The use of early evaluation methods and indirect selection in plants is also of great interest in the improvement for abiotic stresses. For this, it is very valuable to have the knowledge of the relationship between characters, especially if the characters of interest show problems of measurement and identification. Thus the objective was to identify the relationship between determinant characters of the efficiency in the use of nitrogen and phosphorus in maize. For this, 14 inbred lines and 39 hybrids were evaluated in two simple experiments, in high and low availability of N and P in a completely randomized design with two replications in a simple factorial design. The experiments were conducted in a greenhouse at the Federal University of Viçosa, during the month of October 2010. The plants were harvested in the V6 stage. From the material that was collected, the measured characters were dry shoot mass (MPS), specific root area (ARE), lateral root length (CRLat), axial root lenght (CRAxi), as well as the two components of the EU N or P were estimated (utilization efficiency - EUt - and absorbing - EAb). The data was subjected to analysis of variance and path. Significant differences between the genotypes were detected for most of the traits studied in high and low availability, except for the EUt in both nutrient levels and ARE in low N (BN). In the phenotypic correlation matrices, the presence of multicollinearity was diagnosed, at a moderate level, between the characters for the high explanatory N (AN). The characters of the root showed no effects on the EU. Thus, it is possible to conclude that the dry mass of shoots and the efficiency in the absorption are the determinant characters of efficiency in the use of nitrogen of high availability, the first one being the most important. The dry mass shoot of the character is the determinant character of the efficiency in the use of nitrogen in low availability of this nutrient and in the efficiency in the use of phosphorus in high and low availability.