Biostimulatory Influence of Commercial Seaweed Extract on Seed Emergence, Seedling Growth, and Vigor of Winter Rice

Seaweed extract contains plant growth regulators and bio-stimulants that enhance plant growth and development. In Bangladesh, winter rice (Boro rice) in the nursery bed often shows poor seed emergence and weak seedling growth due to low temperature. This problem can be addressed by using seaweed extract as a seed priming agent and bio-stimulant. The objective of this study was to evaluate the effectiveness of seaweed extract (Crop Plus) on seed emergence, seedling growth, and vigor of winter rice in the nursery. Two experiments were conducted at Bangladesh Agricultural University using BRRI dhan89. The laboratory experiment consisted of 17 treatments combining three concentrations of Crop Plus (5000, 10,000 and 15,000 ppm) and four priming durations (6, 12, 18, and 24 h), along with hydro-priming and a no priming as control. Seed priming with 15,000 ppm for 24 h produced the highest germination percentage and superior seedling growth traits. The nursery bed experiment comprised 11 treatments combining two doses (1 mL m⁻² and 2 mL m⁻²) of Crop Plus and five different foliar application schedules, along with a control. All treatments outperformed the control, with the best results from Crop Plus @2 mL m⁻² applied at 20 and 30 days after sowing (DAS). Overall, the treatment involving seed priming with 15,000 ppm seaweed extract for 24 h, followed by nursery application at 2 mL m⁻² at 20 and 30 DAS, resulted in higher germination and improved early growth of winter rice. However, further validation across multiple locations, seasons, and rice cultivars is recommended.