Nitrogênio e inoculação com Azospirillum na qualidade fisiológica e sanitária de sementes de trigo

Abstract

RESUMO: A utilização de sementes de alta qualidade é indispensável para o sucesso da produção agrícola. Assim, o objetivo deste trabalho foi avaliar o efeito da inoculação com Azospirillum brasilense e doses de adubação nitrogenada em cobertura na qualidade fisiológica e sanitária de sementes de trigo. Foram avaliadas separadamente sementes das cultivares BRS 220 e BRS Tangará, cultivadas com e sem inoculação de Azospirillum e cinco doses de nitrogênio em cobertura (0, 30, 60, 90 e 120 kg ha -1 ). Posteriormente, foi instalado o experimento de laboratório, em delineamento inteiramente casualizado em esquema fatorial 2 x 5 (com e sem inoculante × doses), com quatro repetições. Além da qualidade sanitária, determinada pelo método de papel filtro, foi avaliada a qualidade fisiológica das sementes pelos testes de germinação, envelhecimento acelerado, frio, condutividade elétrica, emergência de plântulas em areia, comprimento e massa seca de parte aérea e raiz. Os dados foram submetidos à análise de variância, com comparação de médias para inoculação e regressão para doses de nitrogênio. A qualidade sanitária das sementes de trigo não é influenciada pelas doses de nitrogênio e a inoculação com Azospirillum brasilense. A inoculação das sementes de trigo com Azospirillum brasilense favorece o vigor (envelhecimento acelerado) para a cultivar BRS 220 e massa de parte aérea de plântulas para a BRS Tangará. As cultivares apresentam respostas diferenciadas à adubação nitrogenada para as características de qualidade de sementes. O aumento nas doses de nitrogênio até 120 kg ha -1 melhora a qualidade fisiológica das sementes da cultivar BRS Tangará.ABSTRACT: The use of high quality seeds is essential for successful agricultural production. The aim of this study was to evaluate the effect of inoculation with Azospirillum brasilense and nitrogen fertilization on the physiological and sanitary quality of wheat seeds. Seeds of BRS 220 and BRS Tangará cultivars were evaluated separately, grown with and without inoculation of Azospirillum brasilense and five levels of nitrogen (0, 30, 60, 90 and 120 kg ha -1 ). Subsequently, a laboratory experiment was conducted in a completely randomized design with factorial arrangement of 2 x 5 (with and without inoculation x doses) and four replications. Besides the sanitary quality, determined by the blotter spot test, seed physiological quality was evaluated by the following tests: germination, accelerated aging, cold, electrical conductivity, seedling emergence in sand, and length and dry mass of shoots and roots. Data were submitted to analysis of variance with comparison of means for inoculation and regression for nitrogen doses. Sanitary quality was not influenced by nitrogen application and inoculation with Azospirillum. The inoculation of wheat seeds with Azospirillum brasilense favors increase in vigor (accelerated aging) for BRS 220 cultivar and seedling shoot mass for BRS Tangará cultivar. The cultivars presented differentiated responses to nitrogen fertilization regarding seed qualit...

Action specificity of chemical treatment and inoculation with Azospirillum brasilense in wheat seed on the crop initial growth

“…In a study by Souza et al (2014) with sweet corn cultivation, a reduction was also observed in the vigor of inoculated seeds. However, Brzezinski et al (2014) observed greater vigor of the wheat seeds that were inoculated with Azospirillum. This divergence of responses, mainly in relation to the other cultivars evaluated in the present study, may be related to the interaction between the bacterium with the genotype of the cultivar used or even with the strain selected for inoculation (Fibach-Paldi et al, 2012;Hungria, 2011).…”

“…These phytohormones regulate plant growth, being essential for cell elongation, regulating apical dominance, promoting the formation of lateral and adventitious roots, delaying the onset of leaf abscission, coordinating phototropism and geotropism, among others (Taiz & Zeiger, 2013). However, the agronomic efficiency of the inoculants may vary as a function of wheat growing conditions (Brzezinski et al, 2014).…”

Trinexapac-ethyl and topdressing nitrogen levels on the productivity and physiological quality of graniferous white oat seeds

“…Smiderle et al (2011) studied different N levels and periods of application on the rice cultivar 'BRS Jaçanã' and observed the highest germination at 105 kg.ha -1 N. Carvalho and Nakagawa (2012) stated that an increase in germination percentage in function of N levels is probably due to such a nutrient is related to the formation of embryo and storage organs. Studies carried out with black oat (Nakagawa et al, 1994), white oat (Kolchinski and Schuch, 2004), wheat (Prando et al, 2012b;Brzezinski et al, 2014), sweet corn (Zucareli et al, 2012), and millet (Abrantes et al, 2010) also did not observe N effect on seed germination.…”

Application of Non-Selective Herbicides in the Pre-Harvest of Wheat Damages Seed Quality

“…The pathogen F. graminearum (teleomorph Giberellazeae), causes giberela in cereals, is widely disseminated in the agricultural field areas, and was present in practically all the samples evaluated in our experiment. High levels of rainfall during the harvest period contribute to the infection of seeds [34]. Infected seed dispersal is characterized as the main source of inoculum, briefly rendering the cultivation unfeasible [20].…”