Bragantia (2008) 67, 317-326

Saul Jorge Pinto de Carvalho, Ramiro Fernando López-Ovejero and Pedro Jacob Christoffoleti (2008)
Crescimento e desenvolvimento de cinco espécies de plantas daninhas do gênero Amaranthus
[Growth and development of five weed species of the Amaranthus genus]
Bragantia 67 (2), 317-326
Abstract: The aim of this work was to analyze the growth and the development of five weeds of the Amaranthus genus, under non-competitive conditions. The studied species were: A. deflexus, A. hybridus, A. retroflexus, A. spinosus and A. viridis. Eight periodic evaluations of growth were taken, every 10 days, starting at 20 Days After Seeding (DAS). The variables evaluated per plant were: leaf area; roots, stems, leaves, flowers + fruits and total dry weight; obtaining, from the last variable, the absolute and relative growth rates. The phenologyof the plants was also evaluated. A. deflexus was the species with the shortest vegetative cycle , and with the lowest accumulated dry weight and leaf area; whereas A. retroflexus and A. hybridus were the species which reached the highest values for these variables. A. viridis presented the best ecological adaptability for the conditions of the experiment: it showed fast vegetative development and absolute growth rate, and high accumulation of dry weight and leaf area. These results suggest that A. viridis is a species with high potential to interfere in the agricultural crops, due to the efficient use of the growth resources available by the ambient during its initial growth stages.
Keywords : Pigweed; competition; dry weight; leaf area.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: Portuguese)
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Database assignments for author(s): Pedro Jacob Christoffoleti

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
environment - cropping system/rotation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Amaranthus retroflexus (weed)		Brazil (south)
	Amaranthus hybridus (weed)		Brazil (south)
	Amaranthus viridis (weed)		Brazil (south)
	Amaranthus spinosus (weed)		Brazil (south)
	Amaranthus deflexus (weed)		Brazil (south)