Enhancing Onion Seed Conservation Using Carbon Dioxide-Rich Modified Atmospheres

🌱 Introduction

Onion seeds (Allium cepa L.) are notably short-lived, with viability often declining significantly within 6–12 months under conventional storage. Modified atmosphere (MA) storage—particularly using carbon dioxide (CO₂)-enriched environments—has emerged as a promising method to prolong seed viability and vigor by mitigating oxidative stress, microbial activity, and moisture fluctuations.

🧪 Key Findings from Scientific Studies

1. Seed Viability and Germination

A study on the 'Arka Kalyan' onion variety demonstrated that seeds stored under an atmosphere of 80% CO₂, 5% O₂, and 15% N₂ maintained a germination rate of 78.2% after 12 months, compared to 60.8% in seeds stored in ambient air. Vacuum storage also showed favorable results, indicating the benefits of low-oxygen environments in preserving seed viability. (ijcmas.com)

2. Seedling Vigor and Membrane Integrity

Seeds stored in high CO₂ atmospheres exhibited superior seedling vigor indices and lower electrical conductivity (EC) values, suggesting better membrane integrity. This implies that elevated CO₂ levels help maintain cellular structures, crucial for robust seedling development. (ijcmas.com)

3. Moisture Content and Packaging

Packaging materials significantly influence seed moisture content. Non-perforated polypropylene and polyethylene bags effectively maintained lower seed moisture levels, enhancing longevity. These materials, combined with CO₂-rich atmospheres, create optimal conditions for seed preservation. (pdfs.semanticscholar.org)

4. Microbial and Insect Control

Elevated CO₂ concentrations in storage environments have been shown to suppress microbial growth and insect infestation, contributing to improved seed health and reduced deterioration.

📊 Visual Summary

Figure 1: Germination Rates Over 12 Months(ijcmas.com)

Figure 2: Seedling Vigor Index After 12 Months(ijcmas.com)

Note: The above figures are illustrative summaries based on the cited studies.

✅ Practical Implications

• Optimal Gas Composition: Storing onion seeds in environments with approximately 80% CO₂ and low O₂ levels (around 5%) can significantly enhance seed longevity.
• Packaging Materials: Utilizing hermetic, moisture-resistant packaging materials like non-perforated polypropylene or polyethylene bags is crucial for maintaining low seed moisture content.(pdfs.semanticscholar.org)
• Vacuum Storage: In the absence of controlled atmosphere facilities, vacuum storage presents a viable alternative for prolonging seed viability.(extension.uga.edu)

📚 References

1. Koteshi Lamani et al. (2020). "Effect of Modified Atmospheric Packaging on Seed Longevity of Onion." International Journal of Current Microbiology and Applied Sciences, 9(3): 198-209. (ijcmas.com)
2. Shehata, S.A. et al. (2018). "Effects of Foliar Nutrition on Onion Seed Storage under Modified Atmosphere Packages." Semantics Scholar. (pdfs.semanticscholar.org)
3. Naik, I.S. et al. (2024). "Influence of Modified Atmospheric Packaging on Seed Quality Parameters During Storage in Onion Seed (Allium cepa L.)." Biochemistry Journal, 8(6S): 194-199. (biochemjournal.com)

Implementing CO₂-enriched modified atmosphere storage, coupled with appropriate packaging, offers a scientifically validated approach to enhance the shelf life and quality of onion seeds. This method holds significant promise for seed producers and agricultural stakeholders aiming for sustainable and effective seed conservation strategies.(ijcmas.com)