- Pooja Chaudhary
The local community-based organizations (CBOS), farmer cooperatives and farmer groups at local level practice traditional methods of seed storage which includes: heap and kinio storage, mat bin or Bhakarai, mud bins( Sheri or Kathi), earthen clay pots, metal pots , ormi method. The local materials used in seed storage are: neem, bono, Timur, march , titepati leaves for controlling stored grain pests, sun-drying of seeds and cleaning through winnowing, rinsing containers with oils/kerosene, covering mouth of seed containers with ash and chitaune.
Electrical conductivity (EC) for seed vigour showed that the improved hermetic containers (Metal bins, super grain bags and Purdue) provide higher seed vigour than the conventional ones like fertilizer sack and earthen pots. Mass utilisation of such containers for seed storage not only protect seeds from biotic and abiotic deterioration but also helps in conserving seeds for two consecutive growing season .
Further the improved methods to increase resilience and livelihoods of seed are poly-lined bags or polythene sacks. It is seen that the RH for opened containers Viz. plastic sack and earthen bin also remained concurrent (around 70%) with the ambient RH while the metal bin and super grain bags were found with controlled atmospheric environment internally where RH accounted for below 40%.
Maintaining seed viability and vigor for restoration use
Seeds even if adequately protected during storage, still undergoes deterioration with time. Major factors affecting longetivity of mature, viable and healthy seeds are moisture, storage temperature and pests.
The deleterious effects of seed ageing occur largely due to oxidative processes, which can lead to deterioration of the protein, lipids, RNA and DNA. All of these overall affect the cellular and metabolic integrity of seeds and seedlings.
The seeds which are long lived and can be dried to successfully low moisture content to retain viability and germinatibility under suitable cool conditions are” orthodox” seeds. For these seeds, for each 1% decrease in seed mosture an d for each 5°C decrease in storage temperature, the life of the seed is doubled. For their short term storage, a temperature between 0°C – 5°C is sufficient to maintain the viability.
On the other hand the seeds that are damaged and do not survive dehydration are classified as “recalcitrant” seeds. The viability of these seeds can be maintained when the seeds are allowed to dry slightly with oxygen freely available and at moisture content just less than fully imbibed i.e, 98-99% relative humidity, at optimum temperature varying from 7°C to 17°C for tropical species and -3°C to 5°C for temperate climates.
Seed Longetivity
Seed Longetivity is a measure of how long seeds can be stored and remain viable under a given set of conditions. Under identical conditions , a seed collection of high initial viability would have greater longetivity than a collection of same species with a lower initial viability. For orthodox seeds, the longetivity increases with decrease in seed storage, moisture content and temperature in a quantifiable and predictable way. The Longetivity of recalcitrant seeds on the other hand is a short and can range from few weeks to a few months.
Conclusion
Overall recommendations to farmers included drying seeds to 8-10% moisture level in order to reduce incidence of storage pests; placing storage containers in a dry, damp-proof area with proper sanitation. In addition, storage containers should be located at least 30 cm away from the house walls and 30 cm above the ground placed in a wooden plank. (Author is Bsc Agriculture student at IAAS, TU)
