Effect of brown seaweed (Sargassum wightii) extract application on growth and ‎development of chrysanthemum (Chrysanthemum grandiflorum)‎

Today, increasing the growth and development of plants by using natural organic matter such as seaweed extract is pursued as a goal. In order to investigate effect of using seaweed extract on the growth and yield of chrysanthemum a factorial experiment based on the randomized complete block design with three replications was carried out. The first factor was seaweed extract at three levels (0 (water as control), 10 and 20%) and the second factor was mothod of application at two levels (as spray and fertigation). Rooted cuttings were cultivated in the pots filled by sandy loam field soil. Treatment was performed seven times every two weeks after transferring the rooted cuttings to the main pot. The results showed that the effect of different levels of seaweed extract was positive on the most of traits such as total fresh weight, fresh weight of roots, number of leaves, stem length, number of branches, number of flowers and flower diameter, chlorophylls, carotenoids, leaf soluble carbohydrates and negative on the lipid peroxidation and ion leakage. Also, the effect of the spray application method was notable than fertigation on the vegetative and reproductive growth. Based on the results, it can be suggested that the use of seaweed extract at 10% through spray method can increase the vegetative and reproductive growth of chrysanthemums.