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.
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