Response of Vegetative Growth of Three Bread Wheat Cultivars to Spraying With Spirulina Algae Extract

Seaweed is considered an environmentally friendly bio-stimulant that maintains sustainable agricultural systems and mitigates the effects of environmental pollution caused by chemical inputs. To evaluate the effectiveness of seaweed extract on the physiological growth characteristics of wheat, a field experiment was conducted during the 2023–2024 season at the College of Agricultural Engineering Sciences, University of Baghdad.

A field experiment was conducted randomized complete block design (RCBD) with three replications. The treatments included four concentrations of marine algae (Spirulina) extract (0, 2500, 5000 and 7500 mg L^-1) applied to three wheat cultivars (Adina, Buhouth-22 and Al-Hussein).

Experimental results revealed that concentration of 5000 mg L^-1 was most effective, in increasing plant height, crop dry weight, crop growth rate, SPAD chlorophyll content, spike length and flag leaf area compared to other concentrations. Among the varieties, Al-Hussein cultivar demonstrated significant superiority, recording the highest relative increases across all studied parameters compared to Adina and Buhouth-22. The results indicate that the aqueous extract of seaweed acts as an effective, eco-friendly bio-stimulant for wheat, with the 5000 mg L^-1 concentration yielding the highest physiological performance, representing 29% of the total.