Divergência genética e eficiência no uso do nitrogênio por genótipos de milho visando a produção de óleo e proteína

Abstract

Considering the economic importance of maize (Zea mays L.) for the State of Tocantins and the lack of studies on the effectiveness of nitrogen fertilization on genetic divergence and chemical composition of the grains, was carried out this work. In this regard, there were two corn genotypes competition tests in Palmas-TO, in 2014, one under high N (150 kg ha-1 N) and another under low N (0 kg ha-1 N) coverage in V4 stage in the form of urea. The experimental design used in each trial was a randomized block design with three replications and 18 treatments, which are represented by 13 open-pollinated materials and five commercial cultivars. The characteristics studied were the oil content and protein and oil yields, protein and grains. The genetic diversity held for each level of nitrogen fertilization was obtained by Tocher optimization method. To identify the genotypes suitable for environments, we used the methodology proposed by FAGERIA & KLUTHCOUSKI (1980), which suggests the classification of genotypes for use efficiency, and response to application of nitrogen. The contrasting nitrogen levels resulted in differential behavior of genotypes. The characteristics that most contributed to genetic dissimilarity were grain yield, protein yield and oil yield. The P24-M1 genotypes and P37-3, down N and P24-M1 to high N, are promising for energy production. Efficient genotypes in absorption and utilization of nitrogen through the specific methodology for mineral stress and responsive to nitrogen increment were P36-16, P32-11 and P24- M1.