Biochemical and Physiological Responses of canola (Brassica napus L.) to Seed Coating under Drought Conditions

Document Type : Original Article

Authors

1 Department of Plant Production and Genetics, Faculty of Agriculture and Natural Resources, Mohaghegh Ardabili University, Ardabil, Iran

2 Sugar Beet Seed Breeding and Production Research Institute, Agricultural Research and Education Organization, Karaj, Iran

10.22034/plant.2025.144360.1172

Abstract

Introduction: Canola (Brassica napus L.), as one of the most important oilseed crops, plays a vital role in providing edible oil and biofuels. However, the sensitivity of this plant to drought, especially during germination and early establishment stages, significantly affects its yield. Drought stress is one of the most critical challenges facing sustainable agriculture worldwide, imposing substantial negative impacts on the growth, yield, and quality of crops. In this context, seed coating technology has emerged as an effective strategy to enhance drought tolerance and improve water use efficiency. Seed coatings containing various materials such as hydrogels, nutrients, plant hormones, and plant growth-promoting rhizobacteria (PGPR) can modulate the plant's physiological responses under stress conditions.
Materials and Methods: This experiment was conducted to investigate the effect of seed priming and hydropriming on the physiological traits of canola under drought stress conditions at the Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, in 2020. Certified canola seeds (Hyola cultivar) harvested in 2019 were obtained from the Moghan Agricultural Research and Education Center. The experiment was carried out as a factorial arrangement in a completely randomized design with three replications. Experimental treatments included drought at five levels (0, -2, -4, -6, and -8 bar) and seed coating at six levels (humic acid at three different concentrations, humic acid + hydropriming, hydropriming, and control (no coating)). The present study was conducted separately under laboratory conditions (3 replications of 25 seeds in 15 cm diameter Petri dishes) and greenhouse conditions (5 replications of 6 seeds in 15-liter pots).
Results: Results indicated that the combined treatment of hydropriming along with humic acid (6 grams per kilogram of seed) was the most effective approach significantly mitigating the detrimental effects of drought. There was an 8.5% difference in chlorophyll index, a 284% difference in leaf area (under non-stress conditions), a 167% difference in leaf dry weight, and a 118% difference in root dry weight between the best and worst treatments, demonstrating the high efficacy of seed coating treatments. Although seed coating may reduce germination speed, this delay is compensated for by increased uniformity and final seedling establishment percentage, ultimately leading to the production of more vigorous and resilient plants. Furthermore, the dose-response effects of canola seed coating with humic acid were evident in the experiment, and careful consideration of its application is necessary.
Conclusion: The synergistic effect of combining hydropriming with an optimal concentration of humic acid (6 g/kg seed) yielded the best results. As a practical recommendation, it is suggested that farmers in arid and semi-arid regions first place canola seeds in water (hydropriming) for 12 to 24 hours and then coat them with a quality humic acid solution at an appropriate concentration. This practice will improve initial crop establishment and minimize damage caused by drought during critical growth stages.

Keywords

References

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Plant Production and Genetics
Volume 6, Issue 2 - Serial Number 10
February 2026
Pages 313-326

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