Caracterização de forrageiras quanto à tolerância ao estresse hídrico

Abstract

Water scarcity is the main abiotic factor responsible for low productivity; however, climate change will have impacts on society and biodiversity, causing a decrease in agricultural production, an increase in the vectors of various diseases and the extinction of animals and plants. In this work the aims to was evaluate two cultivars and seven genotypes of Megathyrsus maximus (Jacq.) B.K.Simon & S.W.L.Jacobs for water stress tolerance, through two different methodologies: suspension of irrigation for 18 consecutive days and by applying Polyethylene Glycol 6000 (PEG-6000) for 12 consecutive days. At the moment of suppression of the water supply and the multiple days of three of interruption of the irrigation and the multiple days of four for solution with PEG-6000 the chlorophyll content in the leaves was estimated, noting the number of leaves and the height of the stem. The rate of photosynthesis, transpiration, stomatal conductance and leaf temperature were obtained with an infrared gas analyzer and also, we determined the shoot biomass after stress and after rehydration. The data were submitted to ANOVA and were standardized by the decostand command. The cultivars BRS Tamani and Massai and the genotypes, PM19, PM20 and PM21 were the most tolerant, height and stomatal conductance were not significant in relation to time and cultivar time interaction. The highlight are the cultivars P. maximum cv. Massai and P. maximum cv. BRS Tamani, which although affected by water stress, obtained 100% regrowth and retained all their metabolic activities, and it can be inferred that they relocated their nutrients to the roots in order to wait for better survival conditions. In the second methodology, however, PM44 was highlighted, followed by cultivars Massai and BRS Tamani.