Aspectos fisiológicos e produtivos do amaranto submetido a diferentes períodos de estresse hídrico

Abstract

The cultivated amaranth presents nutritional and agronomic characteristics desirable for the production of biomass and grain with potential to become option to compoud productive systems in the Brazilian Savannah. But, there is deficiency of information about the plant management and the impact of water restriction for commercial production. The objective of this work was to evaluate aspects of growth, production and water relations of amaranth plants under different water regimes.This research was conducted at the Experimental Farm of the Federal University of Mato Grosso, in the municipality of Santo Antônio do Leverger from 30 June to 23 September 2014. he experimental design was that of randomized block in factorial arrangement (2x3) with three repettions, being the first factor the varieties of amaranth (BRS Alegria 'and' INCA ') and the second factor the water stress levels (irrigated plants until 45 days after emergence, irrigated plants until 60 days after emergence and irrigation all cycle ).For quantitative growth analysis were evaluated weekly: plant height, stem diameter, width and length of inflorescence, dry matter and root dry mass. At the end of the trial period were evaluated productive aspects (grain yield, harvest index and grain yield per available unit of water). The parameters of gas exchange (net photosynthesis rate, stomatal conductance, transpiration and efficient use of water) and water relations were evaluated before the stress and harvesting (at 63 days after emergence in the variety Inca and at 84 days after emergence in variety BRS Alegria) The water deficit affected the growth of plants for height, stem diameter and dry matter production for the various organs of the amaranth plant except for the root that had the added mass when the water stress imposed was severe. The Inca variety showed no significant difference between treatments for grain yield. In the variety BRS Alegria better overall the grain yield and grain yield per available unit of water was obtained in the treatment with full irrigation. The severe water deficit caused a decrease in stomatal conductance and photosynthesis. For the variables of water relations could not be verified any effect of the treatments evaluated.