PRODUÇÃO E QUALIDADE FISIOLÓGICA DE SEMENTES DE LINHAGEM DE MILHO EM FUNÇÃO DE DOSES DE NITROGÊNIO E UMIDADE NA COLHEITA

Abstract

Corn production plays an especially important role in the economic development of many countries, so, there is a need for hybrids of excellence in the market to reach this parameter. An initial study on maize lines is essential to obtain hybrids. Parameters such as productivity, precocity, pest resistance, plant diseases, adaptability, plant nutrition, and seed quality are considered to select strains. Some authors state that adequate nitrogen fertilization is needed to increase the corn economic productivity, considering that nitrogen (N) is the most required macronutrient by the crop. This nutrient performs diverse metabolic functions in seeds, contributing to their formation and nutritional reserve. Therefore, this paper aimed to evaluate the production and quality of irrigated corn lineage seeds under nitrogen doses and moisture levels at harvest time. The experiment was carried out from August 2019 to January 2020 in the experimental area of the Goiano Federal Institute, Ceres Campus, Goiás State (GO), Brazil, and in its Seed Analysis Laboratory. The experimental design was in randomized block, 5 x 4 factorial arrangement, split plots, twenty treatments with five nitrogen rates (50, 110, 170, 230, and 290 Kg ha-1), and harvest took place with four moisture degrees (15%, 25%, 35%, and 45%). A maize line from the Limagrain company was used for this study. Plant height, insertion height of the first ear, stem diameter, ear length, ear diameter, number of seeds per row, number of rows, number of seeds per ear, and yield were the variables analyzed in field. Moisture content, standard germination test, weight of a thousand seeds, electrical conductivity, tetrazolium test, accelerated aging test, infested seeds, and nitrogen content in seeds were the variables analyzed in the laboratory. The studied strain tolerates low nitrogen availability and has high efficiency in its use. The strain responds positively to the nitrogen increase in relation to germination percentage with better results above 170 Kg of N ha-1. The strain has high capacity to accumulate biomass in caryopsis even with low moisture content. Seeds harvested with 25% moisture showed satisfactory results for germination and vigor. It is recommended to apply 170 Kg de N ha-1 nitrogen dose split in four times for topdressing the corn lineage studied in this paper.