Modeling of carbon assimilation, growth analysis and morphogenesis of two Brachiaria spp. swards under defoliation frequencies with and without irrigation

• Grant number: 13/15203-4
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: October 01, 2013
• End date: March 31, 2014
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Pastures and Forage Crops
• Principal Investigator: Carlos Guilherme Silveira Pedreira
• Grantee: Ana Flávia Gouveia de Faria
• Supervisor: Lynn E. Sollenberger
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Institution abroad: University of Florida, Gainesville (UF), United States
• Associated to the scholarship: 11/17044-5 - Modeling of carbon assimilation, growth analysis and morphogenesis of two Brachiaria spp. swards under defoliation frequencies with and without irrigation., BP.DR

Abstract

Photosynthesis is the way by which plants assimilate carbon and accumulate dry matter in their tissues, and its understanding is important to define the best management strategies to forage species. One possible approach is the use of models to estimate canopy photosynthesis in response to defoliation strategies. The objective of the present study is to characterize the photosynthesis of two Brachiaria genotypes (hybrid: CONVERT HD 364 and Brachiaria brizantha (A. Rich.) Stapf cv. Marandu) under harvesting and irrigation management strategies, by comparing forage productivity, growth analysis, and morphogenic characteristics to provide insights and understanding of physiological and morphological plant responses to stressed environment. Two parallel field experiments (irrigated and no-irrigated) will be established, in the same time during two years (April 2011-April 2013), at ESALQ/USP Campus Piracicaba-SP, Brazil. The layout was a complete randomized block design with a factorial arrangement, including the following factors: irrigation system (irrigated and no-irrigated), clipping interval (28 and 48 days), and forage genotype. The following variables was measured: leaf appearance rate, leaf elongation rate, leaf senescence rate, stem elongation rate, tiller density, growth, development and senescence, biomass production, leaf area index, light interception by sward, leaf angle, photosynthetic indexes, as well as modeling the CO2 assimilation by forage canopy. Data will be analysed using SAS program, and treatment means compared by Tukey-test at the 5% level of probability. (AU)