Journal of Food, Agriculture and Environment

Vol 9, Issue 3&4,2011
Online ISSN: 1459-0263
Print ISSN: 1459-0255

Multiple regression analysis in competition between lambsquarters and rapeseed


Negar Valizadeh, Bahram Mirshekari *

Recieved Date: 2011-06-09, Accepted Date: 2011-10-06


In order to evaluate of inter-specific competition between lambsquarters (Chenopodium album) and rapeseed (Brassica napus) cultivars, an experiment was performed in a randomized complete block design with three factors including lambsquarters density (5, 10 and 15 weeds/m2), emergence time (simultaneously with rapeseed; 15 and 30 days after rapeseed emergence) and rapeseed cultivar (SLM046, Opera and Okapi). Results indicated that in higher weed densities and early emergence times weed green cover in plots of three cultivars was improved significantly, and increased values in Okapi and SLM046 were higher. When lambsquarters emergence time was delayed and density decreased, weed LAI experienced significant reduction in all rapeseed cultivars. With increasing of lambsquarters density, its leaf area at 75 days after emergence (DAE) decreased from 0.29 to 0.10 m2 in Okapi, 0.36 to 0.12 m2 in Opera and 0.40 to 0.14 m2 in SLM046. Similarly, weed leaf area duration (LAD) was reduced from 0.4, 0.8 and 0.95 m2/day to 0.26, 0.63 and 0.72 m2/day in three studied cultivars, respectively. Yield loss in rapeseed varied from 4.3% with emerging of 5 lambsquarters plants at 30 DAE in Okapi up to 59% in long-season interference of 15 weed plants in SLM046. The stepwise regression analysis verified that the green cover percentage and LAI of weed had a marked increasing effect on the oil yield of rapeseed.


Green cover, interference, lambsquarters, rapeseed, stepwise regression

Journal: Journal of Food, Agriculture and Environment
Year: 2011
Volume: 9
Issue: 3&4
Category: Agriculture
Pages: 525-528

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