Phosphorus Efficiency in Brazilian Soybean Cultivars
Isabeli Pereira Bruno *
Instituto Agronômico do Paraná, Rodovia Celso Garcia Cid, Km 375, CEP: 86047-902, Londrina, Paraná, Brazil
Alinne da Silva
Universidade Estadual da Região Tocantina do Maranhão, R. Godofredo Viana, s/n, CEP: 65900-100, Imperatriz, Maranhão, Brazil
Vinícius Ide Franzini
Empresa Brasileira de Pesquisa Agropecuária, Embrapa Amazônia Oriental, Trav. Dr. Enéas Pinheiro, s/n, Bairro Marco, CEP: 66095-100, Belém, Pará, Brazil
Nericlenes Chaves Marcante
Empresa Brasileira de Pesquisa Agropecuária, Embrapa Cerrados, Rodovia BR-020, Km 18, CEP: 73310- 970, Brasília, Distrito Federal, Brazil
Takashi Muraoka
Universidade de São Paulo, Centro de Energia Nuclear na Agricultura, Avenida Centenário, nº 303, CEP: 13400-970, Piracicaba, São Paulo, Brazil
*Author to whom correspondence should be addressed.
Abstract
The primary goal of this study was to evaluate the phosphorus uptake and use efficiency in Brazilian soybean cultivars, besides root morphology and architecture characteristics related to phosphorus uptake, carrying out two greenhouse experiments. The experiment 1 was completely randomised, with 56 treatments (soybean cultivars) and 3 replicates. Experiment 2 was completely randomised design with three replicates, and the ten cultivars (greater and lower efficiency) were selected for this assay according to their ability to absorb phosphorus less available determined in experiment 1.
The study was carried out at Center of Nuclear Energy in Agriculture, University of São Paulo, Brazil, between February 2011 and August 2012. The isotopic dilution technique was used in the first experiment to assess the phosphorus availability in the soil and to determine the ability of plants to access labile phosphorus by measuring the specific activity of plants grown in soil labeled with radioactive phosphorus. Nine cultivars showed greater phosphorus uptake and used efficiency. The second experiment evaluated the root morphology and architecture. The cultivars with greater uptake efficiency have root morphology and architecture characteristics that favour acquisition of phosphorus from soil compartments that are inaccessible to other cultivars. Phosphorus uptake by plants was not affected by soybean seeds phosphorus content. Identification of these cultivars is very important because it could enable soybean farming in low fertility soils, reducing fertiliser dependence.
Keywords: L value-seed, 32P, root architecture, root morphology