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Planta Daninha

Print version ISSN 0100-8358

Planta daninha vol.5 no.2 Viçosa Dec. 1982

http://dx.doi.org/10.1590/S0100-83581982000200006 

ARTIGOS

 

Avaliação de cultivares de soja (Glycine max (L.) Merril) em competição com Euphorbia heterophylla L. sob três densidades e dois períodos de ocorrência

 

Evaluation of soybean (Glycine max (L.) Merrill) cultivars in competition with Euphorbia heterophylla L. in three densities and two periods of occurrence

 

 

V. M. ChemaleI; N. G. FleckII

IBióloga - Instituto de Pesquisa Agronômica (IPAGRO), Porto Alegre - RS, 90000
IIProfessor Adjunto -Depto. de Fitotecnia da Faculdade de Agronomia da UFRGS - Porto Alegre - RS, 90000. Bolsista do CNPq

 

 


RESUMO

O presente trabalho, conduzido durante o ano agrícola de 1979/80 na Estação Experimental Agronômica de UFRGS, em Guaíba, RS, apresentou como objetivo testar quatro cultivares de soja (Paraná, Prata, Hood e IAS-4) quanto à sua habilidade em concorrer com Euphorbia heterophylla L. (leiteira, amendoim-bravo) estabelecida em três densidades (0, 12 e 54 plan-tas/m2, em média) e dois períodos de duração da competição (45 e 115 dias após a emergência da soja).
Constatou-se que houve redução no rendimento de grãos de soja por efeito dos dois períodos de competição e das densidades de E. heterophylla L. referidas. Também os números de grãos e de legumes por área foram consideravelmente reduzidos pela presença da planta daninha associada ao período mais prolongado de competição.
A espessura do caule e o número de nós das plantas de soja decresceram apenas sob o efeito da maior densidade da Euphorbia; entretanto, o número de ramos e o índice de área foliar, este aos 75 dias após a emergência da cultura, sofreram redução com a infestação de 12 plantas de Euphorbia por m2.

Palavras chave: Plantas daninhas, competição, Euphorbia heterophylla L., soja, cultivares.


SUMMARY

A field experiment was performed at the Agronomy Experimental Station of UFRGS, in Guaíba, RS, Brazil, during the 1979/80 growing season, in order to test four soybean cultivars (Paraná, Prata, Hood e IAS-4) in competition with Euphorbia heterophylla L. established in three densities (0, 12 and 54 plants/m2) during two periods (45 and 115 days after soybean emergence).
It was observed that soybean cultivars presented reduction of seed yields under the effect of the pe riods of competition and densities of Euphorbia heterophylla L. The number of seeds and pods per area were considerably reduced in the presence of the weed associated with the longest competition period.
The stem diameter and number of nodes were reduced only by competition of the highest Euphorbia density; however, the number of branches and leaf area index, this after a period of 75 days of crop-weed association, were already reduced by a density of 12 plants/m2 of Euphorbia heterophylla L.

Keywords: Weeds, competition, Euphorbia heterophylla L., soybean, cultivars.


 

 

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Full text available only in PDF format.

 

 

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Parte da dissertação de mestrado em agronomia do primeiro autor; Faculdade de Agronomia/UFRGS.
Trabalho realizado com recursos financeiros provenientes do CNPq, da EMBRAPA, da FAPERGS e PROPESP/UFRGS.

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