African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6688

Full Length Research Paper

Effect of defoliation from the bottom to the top on the yield of Brazilian soybean cultivars

Amilton Ferreira da Silva
  • Amilton Ferreira da Silva
  • Departament of Plant Science, Universidade Federal de Vicosa, Zip Code 36570-900, Minas Gerais, Brazil.
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Tuneo Sediyama
  • Tuneo Sediyama
  • Departament of Plant Science, Universidade Federal de Vicosa, Zip Code 36570-900, Minas Gerais, Brazil.
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Francisco Charles dos Santos Silva
  • Francisco Charles dos Santos Silva
  • Departament of Plant Science, Universidade Federal de Vicosa, Zip Code 36570-900, Minas Gerais, Brazil.
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Andre Ricardo Gomes Bezerra
  • Andre Ricardo Gomes Bezerra
  • Departament of Plant Science, Universidade Federal de Vicosa, Zip Code 36570-900, Minas Gerais, Brazil.
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Danieli Piano Rosa
  • Danieli Piano Rosa
  • Departament of Plant Science, Universidade Federal de Vicosa, Zip Code 36570-900, Minas Gerais, Brazil.
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Cosme Damiao Cruz
  • Cosme Damiao Cruz
  • Departament of Plant Biology, Universidade Federal de Vicosa, Zip Code 36570-900, Minas Gerais, Brazil.
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Luiz Antonio dos Santos Dias
  • Luiz Antonio dos Santos Dias
  • Departament of Plant Science, Universidade Federal de Vicosa, Zip Code 36570-900, Minas Gerais, Brazil.
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  •  Received: 23 May 2015
  •  Accepted: 12 August 2015
  •  Published: 13 August 2015

Abstract

Among the factors that may cause decreases in soybean yield there are the foliar diseases that despite control it can limit grain yield. The Asian soybean rust (Phakopsora pachyrhizi) is considered the most important disease of soybean in Brazil. The aim of this work was to simulate the progress of Asian rust in Brazilian soybean cultivars by removal of trifoliate leaves from the bottom to the top. The experimental design was a randomized complete block, in a 3x3x5 factorial scheme, with four replications. It was observed that there was significant interaction between cultivars and defoliation for all yield components and consequently in seed yield. Increase in the defoliation intensity towards the bottom to the top during the reproductive stages studied (R3, R5, R6) there is a linear decrease in grain productivity, reaching in the highest defoliation level, loss of 79.6, 77.7 and 38.6% in R3, R5 and R6 stages, respectively. The simulation of damage by soybean rust through defoliation cultivars showed severity in leaf area reduction and its consequent effect in grain seed yield.

 

Key words: Yield components, leaf area, reproductive stage, biotic stress.