Weed Science (2017) 65, 603-613

Muhammad Yasin, Eva Rosenqvist and Christian Andreasen (2017)
The effect of reduced light intensity on grass weeds
Weed Science 65 (5), 603-613
Abstract: The effect of reduced light intensity on the growth and development of three common grass weeds, blackgrass, silky windgrass, and annual bluegrass, was studied. Two identical greenhouse experiments displaced in time were performed with six light levels aiming at 0%, 20%, 50%, 80%, 90%, and 95% shade corresponding to a mean daily light integral (DLI) of 12.4, 9.63, 7.13, 2.74, 0.95, and 0.69 mol m^-2 d^-1 in experiment 1 and 21.2, 18.0, 10.7, 3.71, 1.64, 1.20 mol m^-2 d^-1 in experiment 2. Climate screens of acrylic fabric were used to create the light levels. A DLI of 0.69 to 3.71 mol m^-2 d^-1 substantially reduced the plant height, the number of leaves, leaf chlorophyll content index, stomatal conductance, maximum photochemical efficiency of photosystem II, and dry matter of blackgrass. It also reduced plant height, the number of leaves, and dry matter and delayed flowering of windgrass and annual bluegrass. Annual bluegrass reacted most rapidly when light levels increased from the lowest levels by producing more leaves. DLI thresholds for blooming were estimated to be about 7.13 mol m^-2 d^-1 for windgrass and 1.64 mol m^-2 d^-1 for annual bluegrass. Annual bluegrass was able to bloom and sustain biomass even at a DLI of 1.64 mol m^-2 d^-1. This ability may contribute to an explanation of why annual bluegrass is among the most common weed species in highly competitive and well-fertilized crops even though it is much smaller than the two other grass species.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Christian Andreasen

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

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Alopecurus myosuroides (weed)
	Poa annua (weed)
	Apera spica-venti (weed)