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African Crop Science Journal
African Crop Science Society
ISSN: 1021-9730 EISSN: 1021-9730
Vol. 4, No. 4, 1996, pp. 411-421
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Bioline Code: cs96082
Full paper language: English
Document type: Research Article
Document available free of charge
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African Crop Science Journal, Vol. 4, No. 4, 1996, pp. 411-421
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Tessema, Taye; Tanner, D.G. & Hassena, Mohammed
Résumé
Des etudes durant deux annees etaient conduites en Ethiopie pour
examiner les effets de competition par especes predominantes des adventices
sur le ble (Triticum aestivum L.). Dans le premier essai, les effets
de quatre especes d'adventices (Avena abyssinica Hoechst, Lolium
temulentum L., Snowdenia polystachya Fresca (Pilg), et
Phalaris paradoxa L.) a huit densites de semis (de 0 a 320 m-2) sur
le rendement en grain de ble etaient etuies. A. abyssinica et S.
polystachya etaient hautement competitifs, resultant en une pins grande
reduction du rendement en grain de ble (de 85 et 86% respectivement a 320
plants m-2) que L. temulentum et P. paradoxa. L temulentum
exercait un plus grand effet competitif que P. paradoxa. Le
niveau de competition des adventices variait avec le taux de
germination des adventices. Le second essai etudiait lea interactions
competitives de Avena fatua L. seme a quatre densites (de 0 a 90 m-2)
en competition avec quatre varietes de ble communement cultivees par les
exploitants fermiers en Ethiopie. La variete seminaine Dashen emit la plus
sensible a la competition de A. fatua, exhibant une perte de
rendement de 63% a la densite maximale de 90 plantes d'avoine sauvage m-2 .
Les indices de competition etaient derives de chaque essai pour faciliter
la prediction en perte de rendement en grain de ble et pour deriver les
seuils economiques pour l'intervention d'herbicide en relation avec le taux
de germination des adventices.
Mots Clés
Adventices, ble, competition, herbicide, perte du rendement
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Grass weed competition with bread wheat in Ethiopia: II. Prediction of grain yield loss and implications for economic weed control
Tessema, Taye; Tanner, D.G. & Hassena, Mohammed
Abstract
Two multi-year studies were conducted in Ethiopia to examine the effects of
competition by the predominant grass weed species on bread wheat
(Triticum aestivum L.). In the first experiment, the effects of four
grass weed species (Avena abyssinica Hoechst, Lolium temulentum
L., Snowdenia polystachya Fresen (Pilg), and Phalaris paradoxa
L.) at eight seedling densities (from 0 to 320 m2) on wheat grain
yield were studied. A. abyssinica and S. polystachya were
highly competitive, resulting in a greater reduction of wheat grain yield
(i.e., 85 and 86%, respectively, at 320 seedlings m-2) than L
temulentum and P. paradoxa. L temulentum exerted a greater
competitive effect than P. paradoxa. Competitiveness of the grass
weeds varied with weed seedling density. The second experiment studied the
competitive interactions of Avena fatua L. sown at four seedling
densities (from 0 to 90 m-2) in competition with four bread wheat
cultivars commonly grown by peasant farmers in Ethiopia. The semi dwarf
cultivar Dashen was the most sensitive to A. fatua competition,
exhibiting a yield loss of 63% at the maximum density of 90 wild oat
seedlings m-2. Competitive indices were derived from each experiment to
facilitate the prediction of wheat grain yield loss, and to derive economic
thresholds for herbicidal intervention in relation to weed seedling
density.
Keywords
Competition, grass weeds, herbicide, wheat, yield loss
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© Copyright 1996 - African Crop Science Society
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