Variabilidade genética e caracterização do sistema radical de plantas de milho na eficiência de absorção e utilização de fósforo

• Ano de defesa: 2009
• Autor(a) principal: Brito, Ciro Maia de
• Orientador(a): Miranda, Glauco Vieira
• Banca de defesa: Galvão, João Carlos Cardoso , Berger, Paulo Geraldo
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Genética e Melhoramento
• Departamento: Genética animal; Genética molecular e de microrganismos; Genética quantitativa; Genética vegetal; Me
• País: BR
• Palavras-chave em Português: Milho; Zea Mays L.; Efeito do fósforo; Variabilidade genética; Sistema radical
• Palavras-chave em Inglês: Maize; Zea Mays L.; Effect of phosphorus; Genetic variability; Root system
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::MELHORAMENTO VEGETAL
• Link de acesso: http://locus.ufv.br/handle/123456789/4712

Phosphorus is a nutrient that limits crop production in tropical soils because low levels in the form available to plants and limited mobility. The architecture and spatial distribution of the root system can increase the absorption of some nutrients with low mobility in the soil for the plant. The aim of this study was to identify ideotype the root system for phosphorus absorption and utilization efficiency by plants maize lines with different roots morphologies, the genetic variability of the maize lines for the concentration of fine roots in the first 10 cm of the root system and classify maize lines in efficient and inefficient for efficiencies. The 22 maize lines were evaluated of high and low P. The planting was done in PVC tubes, with four dm3. The substrate was composed of sand (50%), vermiculite (37.5%) and soil (12.5%). The root length and diameter were assessed using the software WinRhizo Pro 2007 connected to a scanner. The lines L20, L4, L16 and L9 in the low P showed root length 10% higher than in high P. The line L20 produced 91% more very fine roots length (VFRL) in low P than high P and is indicative of the adaptive response to the P stress by maize plants. The lines that showed high VFR10 presented high PUtE in low P and high PAE in high P. However, in low P, the PAE was consistent to identify lines with high VFR and FR, but this was not observed in high P. The VFRL50 was not consistent for discriminating efficiency lines for phosphorus absorption or utilization and PA/SR in both environments. A similar result was obtained for thick root length (TRL10 and TRL50) in the two environments. In the low P, L9 lines produced more very fine root and fine root in the 0-10 cm layer and the lines L8, L14 and L17 showed increased production in the 10-50 cm layer. In addition to producing the highest thick root length, the lines L8 and L17 also produces the greatest amount of fine roots at 0-10 cm. It was noted that the 0- 10 and 10-50 cm of the L2 and L22, respectively, produced the lowest number of roots in all diameters. For the discriminant analysis was possible to classify the lines in efficiency and non-efficiency based in the root traits and the P uptake efficiency in the low P. It was concluded that the phosphorus absorption and utilization efficiencies not fully explained by a single specific root trait; It can be obtained root ideotype of maize plants, but these can not be associated with the increased phosphorus absorption and use efficiency; there is the genetic variability among maize lines for traits of root systems in the high and low phosphorus and; multivariate analysis using Anderson discriminant function is effective for simultaneous evaluation of all evidence to the selection of maize most promising.