Herança e correlação entre caracteres de raiz e eficiência de uso do nitrogênio em milho

• Autor(a) principal: Lima, Rodrigo Oliveira de
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4736
• topic: Herança; Correlação; Nitrogênio; Milho; Raiz; Inheritance; Correlation; Nitrogen; Root; Maize; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::MELHORAMENTO VEGETAL

The efficiency of nitrogen fertilization in maize did not exceed 50%. Among the existing proposals to increase the efficiency of nitrogen use in maize stands the higher N uptake from the increase of the root system, especially in environments with low availability of N. The objectives of this work were to study the influence of nitrogen in the genetic variability of root characters and nitrogen use efficiency in maize; to estimate the relationship and unfold in such a direct and indirect effects of root traits on the indices of efficiency nitrogen and whether these estimates are influenced by nitrogen availability and identify the genetic control of root traits and indices of efficiency of nitrogen. For this, 183 F2:3, two inbred lines, the F1 hybrid and the two backcrosses were evaluated in a greenhouse belonging to the Federal University of Viçosa, in the year 2009. The 188 genotypes were evaluated until the four leaf stage developed in cylindrical PVC pots filled with a mixture of sand and vermiculite inert. The experiment consisted of a 188 x 2 factorial (two levels of nitrogen and 188 genotypes) in a randomized complete block with two replications. The experimental unit corresponded to a vase. It used two levels (1 mM and 15 mM), this 75% in nitrate form and 25% as ammonium. We evaluated the following traits: shoot dry weight, root dry weight, root length and volume of lateral and axial, uptake, utilization and use nitrogen. We concluded that no change in the relative performance of genotypes of maize due to the difference in nitrogen levels only for efficient use of nitrogen; the root traits do not explain the difference between genotypes for nitrogen use efficiency in two doses nitrogen; the genetic control of root traits and indices of efficiency of nitrogen are predominantly non-additive effects and the availability of nitrogen did not influence the estimates of gene effects, of the correlation and direct and indirect effects of root traits on efficiency of use nitrogen.