Desempenho de genótipos de milho para a resposta à inoculação com Azospirillum brasilense
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Data
2019-11-08
Autores
Oliveira, Kevyn Belonssi de
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Universidade Estadual Paulista (Unesp)
Resumo
RESUMO - A inoculação com Azospirillum brasilense vem sendo praticada na cultura do milho contribuindo com ganhos na produtividade e reduzindo os impactos ambientais decorrentes da utilização de fertilizantes nitrogenados. Dessa forma, é crescente a busca por genótipos de milho que detenham genes que promovam uma associação eficiente com A. brasilense. O objetivo deste trabalho foi caracterizar genótipos de milho quanto à resposta a inoculação com A. brasilense. Foram avaliados 46 genótipos de milho na primeira safra 2018/19 em Jaboticabal-SP no delineamento de blocos ao acaso com duas repetições. Foram conduzidos na mesma área dois experimentos, sendo um com inoculação de A. brasilense via solo sem a realização de adubação nitrogenada de cobertura (AZOS) e outro com adubação nitrogenada de cobertura sem aplicação de A. brasilense (N), ambos os experimentos receberam adubação nitrogenada no plantio. Avaliou-se a produtividade de grãos, prolificidade, Comprimento da espiga, Diâmetro da espiga, Número de fileiras de grãos na espiga, Número de grãos por fileira, Peso médio de 500 grãos, altura de planta, altura de espiga, posição relativa da espiga, florescimento masculino, florescimento feminino e tombamento de plantas. Os dados foram submetidos ao teste F e comparados pelo teste de Scott-Knott a 5% de probabilidade, também para cada genótipo foi obtida a eficiência na resposta à inoculação com A. brasilense e realizada a análise estatística multivariada por componentes principais. Foi possível caracterizar genótipos de milho quanto à resposta à inoculação com A. brasilense via solo, sendo a resposta à inoculação dependente do genótipo utilizado. Os genótipos 1, 6, 13, 18, 20, 23, 25, 32 e 33 são os mais promissores na resposta à inoculação com A. brasilense, com aumento na nos componentes da produção. Os genótipos 12, 13, 23, e 27 apresentaram os melhores desempenhos ao uso de A. brasilense para os caracteres morfoagronômicos. Estes genótipos selecionados são indicados para compor populações base de programas de melhoramento genético de milho para o uso do A. brasilense, contribuindo com o avanço e continuidade da pesquisa.
ABSTRACT - Azospirillum brasilense inoculation has been practiced in maize crop improving grain yield and reducing the environmental impacts resulting from the use of nitrogen fertilizers. Thus, the search for maize genotypes with genes that promote an efficient association with A. brasilense is increasing. The aim of this study was to characterize maize genotypes in response to inoculation with A. brasilense, using 46 maize genotypes in the summer growing season 2018/19 in Jaboticabal-SP in a randomized complete block design with two replications. Two experiments were carried out in the same area, one with A. brasilense inoculation via soil without nitrogen fertilization (AZOS) and another with nitrogen fertilization without A. brasilense (N). The evaluated traits were: grain yield, prolificacy, ear length, ear diameter, lines per spike, number of grains per line, average weight 500 grains, plant height, ear height, relative ear position, male flowering, female flowering and tipping of plants. The data were submitted to the F test and compared by the Scott-Knott test at 5% probability. For each genotype was obtained the efficiency in response to inoculation with A. brasilense and multivariate statistical analysis was performed by principal components. It was possible to characterize maize genotypes in response to inoculation with A. brasilense via soil, and the response to inoculation was dependent on the genotype used. The genotypes 1, 6, 13, 18, 20, 23, 25, 32 and 33 are the most promising in response to inoculation with A. brasilense, with increased in production components. Genotypes 12, 13, 23, and 27 showed the best performance when using A. brasilense for plant traits. These selected genotypes are indicated to compose base populations of maize genetic breeding programs for the use of A. brasilense, contributing to the progress and continuity of the research.
ABSTRACT - Azospirillum brasilense inoculation has been practiced in maize crop improving grain yield and reducing the environmental impacts resulting from the use of nitrogen fertilizers. Thus, the search for maize genotypes with genes that promote an efficient association with A. brasilense is increasing. The aim of this study was to characterize maize genotypes in response to inoculation with A. brasilense, using 46 maize genotypes in the summer growing season 2018/19 in Jaboticabal-SP in a randomized complete block design with two replications. Two experiments were carried out in the same area, one with A. brasilense inoculation via soil without nitrogen fertilization (AZOS) and another with nitrogen fertilization without A. brasilense (N). The evaluated traits were: grain yield, prolificacy, ear length, ear diameter, lines per spike, number of grains per line, average weight 500 grains, plant height, ear height, relative ear position, male flowering, female flowering and tipping of plants. The data were submitted to the F test and compared by the Scott-Knott test at 5% probability. For each genotype was obtained the efficiency in response to inoculation with A. brasilense and multivariate statistical analysis was performed by principal components. It was possible to characterize maize genotypes in response to inoculation with A. brasilense via soil, and the response to inoculation was dependent on the genotype used. The genotypes 1, 6, 13, 18, 20, 23, 25, 32 and 33 are the most promising in response to inoculation with A. brasilense, with increased in production components. Genotypes 12, 13, 23, and 27 showed the best performance when using A. brasilense for plant traits. These selected genotypes are indicated to compose base populations of maize genetic breeding programs for the use of A. brasilense, contributing to the progress and continuity of the research.
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Palavras-chave
Bactérias diazótróficas, Nitrogênio, Produtividade de grãos, Zea Mays