The variance analysis showed significant effects (p < 0.05) of inoculation (Londrina environment) and N rates (both environments) only for grain yield. There was no inoculation effect in the grain yield when inoculants were applied together with N-fertilization at topdressing. In the absence of N-fertilization at topdressing, the inoculants Masterfix L. and UEL promoted higher grain yield as compared to the uninoculated plants, with resulting increases of 13.21 and 26.61% in yield, respectively.

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R ESU M OPara avaliar o desempenho agronômico da cultura do milho (Zea mays) de segunda safra submetido à inoculação com Pseudomonas fluorescens sob níveis de adubação NPK, um experimento em campo foi conduzido utilizando-se a cultivar de milho híbrido 30F35 cultivada em Latossolo Vermelho eutroférrico. Foram testados seis tratamentos sob o delineamento experimental de blocos casualizados, em esquema fatorial 3 x 2, sendo três níveis de adubação química com NPK (0, 125 e 250 kg ha -1 ) e dois níveis de inoculante à base de P. fluorescens (com e sem), com quatro repetições. Foram avaliados as características fitométricas, os componentes de produção e a produtividade de grãos do milho. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey p < 0,05. A inoculação com Pseudomonas fluorescens associada à adubação de semeadura com 250 kg ha -1 de NPK, favorece o desenvolvimento e o desempenho produtivo do milho de segunda safra. Palavras-chave: Zea mays, Pseudomonas fluorescens, componentes de produção, produtividadeAgronomic performance of maize under mineral fertilizer and seed inoculation with rhizobacteria A B ST R A C T To evaluate the agronomic performance of second maize (Zea mays) crop, subjected to inoculation with Pseudomonas fluorescens under different levels of NPK fertilization, a field experiment was conducted using the cultivar of hybrid maize 30F35 grown in Oxisol. Six treatments were tested in a randomized block design in factorial scheme 3 x 2, with three levels of NPK (0, 125 and 250 kg ha -1 ) and two levels of inoculants (with and without), and four replications. The characteristics, yield components and productivity were evaluated. The data were submitted to analysis of variance and means compared by Tukey test at p < 0.05 level. The inoculation with Pseudomonas fluorescens associated with fertilization with 250 kg ha -1 NPK at sowing time promotes the development and productive performance of second maize crop.

Chemical composition of corn grains in response to mineral fertilization and inoculation with rhizobacteriaTo increase agricultural productivity in the country, studies are needed to improve the utilization of mineral fertilizers in order to produce grains with improved nutritional quality. The study aimed to evaluate the content and accumulation of protein, ash and nutrients in corn grains from plants inoculated with Pseudomonas fluorescens and grown under different levels of NPK fertilizer in the soil. We tested six treatments in a randomized complete block design in a factorial 3 x 2, three levels of chemical fertilizer NPK (0, 125 and 250 kg ha -1 ) and two levels of inoculation using P. fluorecens (with and without), with four replicates, in a Oxisol, using the maize hybrid 30F35. The content and accumulation of N, P, K, Ca, Mg, Zn, Cu, Fe, Mn, protein and ash content of the grains were evaluated. The data were submitted to Anova and means compared by the Tukey test p<0.05. The application of Pseudomonas fluorescens via inoculation increased the P and K of corn, regardless of fertilization levels. The contents of nutrient, protein and ash of corn were not influenced by the levels of mineral fertilization, except for Cu which increased with increasing levels of fertilization. Para o aumento da produtividade agrícola no País, são necessários estudos para melhor aproveitamento da adubação mineral, a fim de uma produção de grãos com melhor qualidade nutricional. Este trabalho teve como objetivo avaliar o teor e o acúmulo de proteína, de cinzas e de nutrientes em grãos de milho provenientes de plantas submetidas à inoculação com Pseudomonas fluorescens e cultivadas em diferentes níveis de adubação NPK no solo. Foram testados seis tratamentos, em delineamento experimental de blocos casualizados, no esquema fatorial 3 x 2, sendo três níveis de adubação química com NPK (0,125 e 250 kg ha -1 ) e dois níveis de inoculante à base de P. fluorescens (com e sem), com quatro repetições, sendo instalado em Latossolo Vermelho eutroférrico, utilizando o cultivar de milho híbrido 30F35. Determinaram-se os teores e acúmulo de N, P, K, Ca, Mg, Zn, Cu, Fe, Mn, proteína e cinzas dos grãos. Os dados foram submetidos à análise de variância e as médias, comparadas pelo teste de Tukey (p < 0,05). A aplicação de P. fluorescens via inoculação incrementou os teores de P e K dos grãos de milho, independentemente dos níveis de adubação. Os teores dos nutrientes, de proteína e de cinzas dos grãos de milho não foram influenciados pelos níveis de adubação mineral, com exceção do Cu, que aumentou com a elevação dos níveis de adubação. Palavras-chave:Zea mays, Pseudomonas fluorescens, macronutrientes, micronutrientes, qualidade nutricional.

The use of plant growth regulators in agriculture can alter the morphology of corn plants, increasing crop yield due to the possibility of increasing the population. This study aimed to evaluate the effects of plant populations associated with trinexapac-ethyl (TE) doses on the biometric characteristics of shoot and grain yield of contrasting corn cultivars regarding plant architecture. Experiments were conducted in the field during two seasons with the hybrids 2B710 HX (flat leaf) and TL Status (erect leaf) in a randomized block design (four replications) and treatments in a 5 × 5 factorial scheme, with five plant populations (40, 60, 80, 100, and 120 thousand plants ha−1) and five TE doses (0, 100, 200, 300, and 400 g a.i. ha−1) applied by foliar spraying at the V6 stage. Plant height, ear insertion height, stem diameter, leaf area index, and grain yield were evaluated. An increment in population increases plant height, ear insertion height, and the leaf area index, but reduces stem diameter. The plant growth regulator TE reduces plant height and ear insertion height. The interaction between plant population and TE favors corn yield, with the highest values observed in combinations of 93.4 thousand plants ha−1 with a dose of 176 g ha−1 of TE for the hybrid 2B710 HX and 92.2 thousand plants ha−1 with a dose of 251 g ha−1 of TE for the hybrid Status TL.

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Reduced row spacing promotes more uniform spatial distribution of plants in the field. However, the adoption of reduced row spacing only is possible with smaller plants, which may be obtained with the use of plant growth regulator. This study aimed to evaluate the agronomic performance of the first corn crop with Trinexapac-ethyl applied at the different plant development stages and grown under different row spacing, with the same plant population. The experiments were arranged in a split-plot randomized block design with four replications, with row spacing for the plots (0.45 and 0.90 m) and Trinexapac-ethyl (TE) application time to subplots (control without application, at the V3, V6, V9 and V12 phenological stages). The Trinexapacethyl application time interacted with row spacings changing the growth and yield performance of the corn crop. For 0.45 m spacing Trinexapac-ethyl application at V12 and for 0.90 m spacing application at V9 and V12 reduced plant height and ear height. Trinexapac-ethyl application at V9 for both row spacings changed the plant architecture without changing the ear length and grain yield.

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