Asian Seed Congress 2017 Standing Committee: Seed Technology Meeting
For the final of the seven technical sessions, APSA’s Standing Committee on Seed Technology welcomed renowned seed and biotechnology academic, Professor Kent Bradford (Director, Seed Biotechnology Center, University of California Davis), whose work and expertise spans diverse areas of seed science, from seed germination and conservation to mathematical modeling and molecular biology.
Prof. Bradford presented his popular and proven viability-optimising “dry chain” model for maintaining seed quality.
The model provides a basis for developing effective alternatives to the commonly used methods of handling and storing seeds that have been harvested with high moisture content, in warm temperatures – conditions that prevail throughout tropical and subtropical climes across Asia and the Pacific. Such conditions are linked to the rapid loss in viability of seeds.
Herrington’s law states, “seed longevity doubles for every 1% decrease in moisture content or every 6°C decrease in temperature”. So moisture is the main factor determining the duration of the storage. Professor Bradford sees the longevity of seed as a metronome. Bradford’s Metronome Rule, states “the ‘clock’ starts running as soon as the seeds are mature and they have a total number of ticks before death.
The rate at which the metronome ticks, depends upon the temperature and moisture content”. What seed industry players are trying hard to do is to slow down the rate of the metronome tick in order to give seeds a long storage life.
Previously demonstrated successfully in several South Asian countries, the dry chain All of the presentations were recorded and are available to APSA members online in the Members only section of apsaseed.org model is put into practice immediately after harvest and continues throughout the value chain.
A scaling up project of using desiccant-based drying beads for storage has now been demonstrated in Bangladesh with three seed companies. After taking into account investment in infrastructure and training in these companies, the scheme has been a great success commercially.
So other companies and government agencies are now starting to adopt this new technology. The process not only increases seed viability, but it has also been demonstrated to reduce overall storage costs.
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