What are the factors that affect the longevity of seeds during storage in warehouses? Describe.

Factors Affecting Seed Longevity During Storage

Seed longevity isn't a fixed property; it's influenced by a complex interplay of genetic and environmental factors. These can be broadly categorized as genetic, environmental, and those related to storage practices.

1. Genetic Factors

• Species and Variety: Different species and varieties exhibit varying degrees of longevity. Some species, like rice and wheat, generally have shorter longevity compared to others like barley or sorghum.
• Seed Size and Structure: Larger seeds often have thicker seed coats, which offer better protection against moisture loss and pest attacks, potentially extending longevity.
• Seed Dormancy: Dormant seeds require specific conditions to germinate, which can also contribute to longer storage life by delaying germination until favorable conditions arise.

2. Environmental Factors

• Temperature: High temperatures accelerate metabolic processes, leading to increased respiration and faster deterioration. Lower temperatures generally extend longevity, though freezing can damage some seeds. The Arrhenius equation describes the relationship between temperature and reaction rate, directly applicable to seed deterioration.
• Relative Humidity (RH): Moisture content is a critical factor. High RH promotes microbial growth and enzymatic activity, leading to rapid deterioration. Low RH can cause desiccation damage, affecting membrane integrity. The critical moisture content for long-term seed storage typically ranges between 5-8%, depending on the species.
• Oxygen Availability: Oxygen is required for respiration. While essential for viability, excessive oxygen can promote oxidative damage. Modified atmosphere storage (reducing O₂ and increasing CO₂) can extend longevity.
• Light: Exposure to light can trigger premature germination and damage seed tissues, particularly in light-sensitive species.

3. Storage-Related Factors

• Packaging: Packaging materials must provide a barrier against moisture, oxygen, and light. Moisture-proof bags (e.g., aluminum-lined bags, polyethylene bags with vapor barriers) are essential.
• Pest and Disease Control: Insects and pathogens can damage seeds and accelerate deterioration. Proper fumigation and sanitation are crucial.
• Warehouse Design and Management: Proper ventilation, temperature and humidity control, and regular monitoring are vital for maintaining optimal storage conditions.
• Seed Handling: Rough handling can cause physical damage, creating entry points for pathogens and accelerating moisture loss.

Storage Condition	Temperature (°C)	Relative Humidity (%)	Oxygen Level	Longevity Impact
Ambient (Uncontrolled)	25-35	60-80	Normal	Short (few years)
Cool (Refrigerated)	5-10	40-50	Normal	Moderate (5-10 years)
Cold & Dry	-18 to -20	10-15	Modified (low O2)	Long (decades or even centuries)

Best Practices for Warehouse Management

• Regular Monitoring: Continuous monitoring of temperature and humidity using data loggers.
• Pest Control: Implementation of integrated pest management (IPM) strategies, including fumigation with phosphine or carbon dioxide.
• Seed Cleaning and Grading: Removing damaged or diseased seeds before storage.
• Proper Ventilation: Ensuring adequate air circulation to prevent moisture buildup.
• Rotation of Seed Stocks: Implementing a "first-in, first-out" (FIFO) system to minimize storage time.

The National Seed Bank of Svalbard (Norway) exemplifies best practices in long-term seed storage, utilizing extremely low temperatures and controlled humidity to preserve seeds for future generations. This facility serves as a 'doomsday vault' safeguarding global biodiversity.

The Seed Act, 1966 (amended in 2004) in India regulates the production and sale of seeds, emphasizing quality control and storage conditions, though enforcement remains a challenge.