African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6578

Full Length Research Paper

Growth and physiological responses of sunflower grown under levels of water replacement and potassium fertilization

Guilherme de Freitas Furtado
  • Guilherme de Freitas Furtado
  • Academic Unit of Agricultural Engineering, Federal University of Campina Grande, Campina Grande, CEP 58.109-970, Paraíba, Brazil.
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Diego Azevedo Xavier
  • Diego Azevedo Xavier
  • Academic Unit of Agricultural Engineering, Federal University of Campina Grande, Campina Grande, CEP 58.109-970, Paraíba, Brazil.
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Elysson Marcks Gonçalves Andrade
  • Elysson Marcks Gonçalves Andrade
  • Academic Unit of Agricultural Engineering, Federal University of Campina Grande, Campina Grande, CEP 58.109-970, Paraíba, Brazil.
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Geovani Soares de Lima
  • Geovani Soares de Lima
  • Academic Unit of Agricultural Engineering, Federal University of Campina Grande, Campina Grande, CEP 58.109-970, Paraíba, Brazil.
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Lúcia Helena Garófalo Chaves
  • Lúcia Helena Garófalo Chaves
  • Academic Unit of Agricultural Engineering, Federal University of Campina Grande, Campina Grande, CEP 58.109-970, Paraíba, Brazil.
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Ana Carolina Feitosa de Vasconcelos
  • Ana Carolina Feitosa de Vasconcelos
  • Academic Unit of Agricultural Engineering, Federal University of Campina Grande, Campina Grande, CEP 58.109-970, Paraíba, Brazil.
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José Alberto Calado Wanderley
  • José Alberto Calado Wanderley
  • Academic Unit of Agricultural Engineering, Federal University of Campina Grande, Campina Grande, CEP 58.109-970, Paraíba, Brazil.
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  •  Received: 28 January 2016
  •  Accepted: 10 March 2016
  •  Published: 30 April 2016

Abstract

Water deficit is one of the limiting factors of agricultural production, especially in semi-arid regions. In this sense, the aim of this study was to evaluate the growth and the physiological characteristics of sunflower cv. Hélio 251 at different levels of water replacement and potassium doses in an experiment conducted in the greenhouse of the Center for Technology and Natural Resources of UFCG, Campina Grande, PB. The experiment was laid out in  randomized complete block design, by studying five levels of water replacement (40, 60, 80, 100 and 120% of actual evapotranspiration - ETr) associated with potassium fertilizer levels (50; 75; 100; 125 and 150% of the indication for assays). The increase of water replacement levels promoted increase in plant height, stem diameter, number of leaves per plant, leaf area, and dry biomass of leaves, and dry biomass of the stem. The level of 75.25% of ETr provided the highest leaf dry weight (0.88 g). The increase in water replacement from 51.33% of ETr provided a reduction in the SPAD index. Water replacement lower than 100% ETr affected gas exchange of sunflower plants, reducing rate of the rate of the photosynthesis by 66% by the water deficit in the soil. The potassium doses had no effect on sunflower growth at 45 DAS neither they altered gas exchange in sunflower plants in the grain filling stage.

Key words: Helianthus annuus L., water stress, SPAD index, gas exchange, rate of the photosynthesis.