Document Type : Research Paper
Authors
1
Department of Crop Physiology, University of Mohaghegh Ardabili, Ardabil, Iran.
2
Department of Agronomy and Plant Breeding, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran.
3
Sugar Beet Seed Institute(SBSI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.
4
Soil and Water Research Institute(SWRI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.
5
Crop and Horticultural Science Research Department, Ardabil Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Moghan, Iran.
10.22092/ijsr.2026.370813.790
Abstract
Background and Objectives: Canola (Brassica napus L.) is a vital global oilseed crop, critical for food security due to its high-quality edible oil and protein-rich meal. Enhancing productivity is a primary goal in modern sustainable agriculture, especially in semi-arid regions where suboptimal environmental conditions often hamper germination and seedling establishment. These early-stage stressors lead to poor crop stands, reduced seedling vigor, and ultimately lower final yields. To address these limitations, seed coating has emerged as a precise and resource-efficient method for improving seed performance. By creating a favorable micro-environment (spermosphere) and delivering beneficial substances directly to the embryo, this technique enhances establishment. Biostimulants, such as seaweed extracts (rich in phytohormones like auxins and cytokinins), humic acids (known for chelating nutrients and stimulating root development), and amino acids (essential for protein synthesis and stress tolerance), are effective additives. While their benefits in foliar applications are well-known, their efficacy and optimal concentrations via seed coating require further investigation. This study aimed to comprehensively evaluate the effects of seed priming and coating with various concentrations of humic acid, seaweed extract, and amino acids, individually and in combination, on the yield and yield components of spring canola.
Materials and Methods: A field experiment was conducted during the 2018-2019 growing season at the research farm of the University of Mohaghegh Ardabili in northwestern Iran, a region characterized by a semi-arid, cold climate. The soil was a calcareous loam (pH 7.8, EC 1.15 dS/m) with low organic matter. The experiment utilized a Randomized Complete Block Design (RCBD) with three replications. The study involved 16 distinct seed pre-treatments applied to the spring canola cultivar 'Hyola 50'. Treatments included three levels of humic acid (3, 6, and 9 g/kg seed), three levels of seaweed extract (3, 6, and 9 g/kg seed), and three levels of amino acids (2, 4, and 6 g/kg seed), alongside specific combined formulations and hydropriming controls. An aqueous slurry containing carboxymethyl cellulose (CMC) as a filler and polyvinyl acetate (PVA) as a binder was used for uniform coating via a laboratory rotary coater. Standard agronomic practices were followed throughout the season. At physiological maturity, plants were harvested to determine grain yield, biological yield, harvest index, and key yield components. Data were analyzed using SAS software (ANOVA), and means were compared using Duncan's Multiple Range Test (DMRT) at the 5% probability level.
Results: Analysis of variance revealed significant effects (P < 0.01) of seed treatments on grain yield, biological yield, the number of pods per plant, 1000-grain weight, and plant height. However, no statistically significant differences were observed for harvest index, pod length, and the number of seeds per pod, suggesting these traits may be less responsive to seed treatments. Grain yield was significantly impacted; the highest yield of 2185.3 kg/ha was achieved by coating seeds with 9 g/kg seaweed extract, representing a substantial 38.76% increase over the control (1574.8 kg/ha). Similarly, coating with 9 g/kg humic acid resulted in the highest biological yield (6941.3 kg/ha) and the maximum number of pods per plant (96.22), showing increases of 21.98% and 62.50% compared to the control, respectively. The 1000-grain weight was also significantly improved by 9 g/kg seaweed extract. Among the combined treatments, the specific combination of 2 g amino acid + 6 g seaweed extract + 3 g humic acid per kg seed demonstrated superior performance in improving plant height and overall yield stability compared to other combinations, highlighting synergistic effects at specific ratios.
Conclusion: This study confirms that seed coating with biostimulants is a potent strategy for enhancing spring canola productivity in semi-arid regions. The targeted application of these substances leads to significant improvements in seedling establishment, vegetative growth, and final grain yield. Application of 9 g/kg seaweed extract is specifically recommended for maximizing grain yield due to its hormonal influence, while high concentrations of humic acid (9 g/kg) are superior for boosting biomass and sink capacity, i.e., pods. The results also indicated that optimized combined treatments can further enhance plant performance. Therefore, seed coating serves as a valuable, precise tool for sustainable production. However, since this study was conducted over a single growing season, further multi-year and multi-location trials are recommended to confirm the stability and generalizability of these findings under varying climatic conditions.
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