Desenvolvimento de Cultivares de Milho (Zea Mays) Em Ambiente de Várzea e Estufa de Cultivo

Abstract

Corn is recognized as one of the most important agricultural crops, environmental changes can lead to lost productivity. The objective of this work was to evaluate the yield and development of this crop under traditional mode of cultivation and under two lighting conditions and three nitrogen doses. The field research was conducted in the Urucurituba Agroextractivist Settlement Project, located in the várzea region of Santarém / PA, the soil is classified as eutrophic Flubic Neosol, the design was in a randomized block design, the treatments being maize cultivars: a Bandeirante variety and the double hybrid AG1051. The cultivar greenhouse experiment was conducted at the UFOPA Experimental Farm in the municipality of Santarém to compare the development of hybrid corn AG 1051 with the Bandeirante variety in two light conditions, 100% and 50% light and under three nitrogen doses, 0 gr.pl-1; 0,46 gr.pl-1 ; 0,92 gr.pl-1. In the field experiment, plant height, stem diameter, leaf dry mass, stem dry matter and dry mass of grain were evaluated, and it was evaluated the highest productivity of dry grain mass, which was 29.3% higher than that of AG1051, stem dry mass and total dry mass were also significantly higher for this cultivar, as well as showing a correlation positive between stem dry mass and leaf dry mass (r = 0.65), which is desirable for silage production . In the greenhouse experiment the cultivars presented geometric growth pattern for plant height and stem diameter in all treatments. The luminosity of 50% negatively affected the accumulation of dry mass of the aerial part. There was interaction between the nitrogen and cultivar doses for the nitrogen content parameter in the leaf and the multivariate analysis showed no differences among the cultivars at dose 0 of nitrogen. It is concluded that the Bandeirante variety is the most adapted to the cultivation in this region for the system of cultivation of the traditional populations, small doses of nitrogen did not affect the growth of the plants and the light stress impairs the development of the aerial part of the corn.