Produtividade e qualidade fisiológica de sementes de cevada em função da adubação nitrogenada

Abstract

In barley, nitrogen is one of the main nutrients that influences the quality and productivity of seeds, since it participates in numerous metabolic routes. It is a limiting factor of the production, the lack or the excess can bring consequence to the culture. The objective of this work was to evaluate the use of different doses of nitrogen fertilization in the productive and physiological quality parameters of two barley cultivars BRS Brau and BRS Cauê. The experimental design was a randomized block design, organized in a factorial scheme, being 2 x 2 x 4 (cultivation environment x). The experiment was carried out in the city of Alegrete-RS and Pelotas-RS, state of Rio Grande do Sul. cultivars x doses of nitrogen), arranged in four replicates, totalizing 32 experimental units. Chapter I comprised the analysis of components of seed productivity, composed of plant height, number of tillers per plant, number of ears per square meter, number of seeds per plant, mass of one thousand seeds and seed yield. Chapter II included the evaluation of the physiological quality of the seeds by germination tests, first counting of germination, accelerated aging, field emergence, shoot length and seedling root, dry mass of shoot and root of seedlings, electrical conductivity (3, 6 and 24 hours) and isoenzymes. In chapter I the components of productivities were influenced by the nitrogen dose and the growing environment, the increment of the dose brings increases in the final productivity, the cultivar BRS Cauê produced in Pelotas-RS obtained the maximum yield of seeds, reached in the dose of 200 kg ha-1. For the quality of the seeds in chapter II, the culture environment promoted differentiation in the physiological quality, comparing the locations, the environment of Pelotas-RS, resulted in the production of more vigorous seeds, resistant to climatic adversities. The use of nitrogen fertilization at the dose of 120 kg ha-1 resulted in the best physiological quality, allied to the cultivar BRS Cauê, in both environments studied.