Impact of water and nutritional stress on nodulation and mycorrhizal colonization in soybeans tolerant to ammonium glufosinate herbicide

• Grant number: 17/22254-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2018
• End date: September 30, 2019
• Field of knowledge: Agronomical Sciences - Agronomy - Crop Science
• Principal Investigator: Pedro Jacob Christoffoleti
• Grantee: Francielli Santos de Oliveira
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

Soybean is a crop of great importance for Brazilian economy and counts on the association of soil microorganisms, such as arbuscular mycorrhizal colonization and nodulation for its good development. Considering that the adoption of technologies of weed management and stress situations can generate impacts on such relationships, the objective is to verify the effects caused by water and nutritional stresses on soybeans tolerant to the herbicide glufosinate ammonium in relation to the associations nodulation microbial and arbuscular mycorrhizal colonization, compared to soybean tolerant to the glyphosate herbicide. The experiment will be conducted in a greenhouse belonging to the Department of Plant Production and will count as evaluations in the laboratories of microbiology and mineral nutrition of plants, belonging to the Department of Soils, both in the dependencies of the "Luiz de Queiroz" School of Agriculture (ESALQ / USP). The experimental design will be completely randomized in a 2 x 2 x 2 factorial scheme, the first factor corresponding to the water condition (water deficit (DH-) and water supply (DH +)), the second factor is the nutritional condition (nutritional deficit (DN- ) and nutritional supply (DN +)) and the third factor to the herbicide treatment (without application (H) and with application (H +)). This factorial scheme will be carried out in isolation for each transgenic soybean variety (soybean cultivar tolerant to the herbicide glufosinate ammonium (LL) and soybean cultivar tolerant to the herbicide glyphosate (RR)). The soybean cultivar (LL) will be treated with the herbicide glufosinate ammonium (500 g i.a. ha-1), as well as the cultivar (RR) will be treated by the herbicide glyphosate (1440 g a.i. ha-1). counting with five replicates per treatment. The nodulation will be evaluated by weighing the nodules after drying in an oven at 60ºC for 72 hours, since the arbuscular mycorrhizal colonization will be determined by the staining method proposed by Vierheilig et al. (1998) and by the cross-sectional method of Giovannetti and Mosse (1980), and nitrogen and phosphorus foliar contents will be determined by standard procedures of the laboratory of mineral nutrition of plants. Therefore, it is expected that at the end of the experiment it will be possible to evaluate the effect of the water and chemical stresses on soybean tolerant to glufosinate ammonium and its microbiological associations in relation to conventional soybean and tolerant to the herbicide glyphosate.