This work aims to verify the influence of different doses of nitrogen, applied in soil
fertilization, upon the morpho-agronomic characteristics of the corn seedlings and adult plants
and biochemical markers (protein electrophoresis and isoenzymes) of corn seeds. Seeds of five
lines and of three hybrids coming from the corn breeding program of the Universidade Federal de
Lavras, UFLA, produced under three doses of nitrogen, zero, 60 and 120kg of N/ha. The evaluation
of the morpho-agronomic markers was perforned at the seedling and plant stage. The electrophoresis
patterns of total proteins of the zein fraction and non-zein fraction and the electrophoresis patterns
of the isoenzyme catalase, esterase and malate dehydrogenase. The results showed that the increase
on the doses of nitrogen applied affected the number of seedling leaflets, date of blossoming, and
the height of plants and insertion of the first ear, but it did not affect the color of leaves, levels of
anthocianin, number of hairs, and the color of anthers, glumes and style-stigma.The pattern of
total proteins, zein fraction and of the isoenzymnes esterase, malate dehydrogenase were not altered
with increased nitrogen fertilization, indicating them to be safe for the certification of genetic
purity and identification of cultivars. The patterns of isoenzyme catalase and non-zein fraction
were altered in terms of nitrogen fertilization.