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8 Cards in this Set
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Main factors that affect wuality |
Temperature Moisture content Seed hygiene Seed dressings |
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Moisture content |
High seed moisture content is related to an increase of reactions that can lead to loss of seed viability for example DNA. These reactions operate more if fictively at elevated moisture content's. Repair mechanisms within the seed for example Ligase enzyme May not be able to operate. Seed moisture content for safe storage for medium term as between 5 to 14%. Above this moisture content's are ideal for fungal growth and other microorganisms that also cause loss in viability of the seed. The same composition can determine if SMC for example seeds with high amounts of carbohydrates have a better ability to hold moisture than a seed with high lipid content. Seed storage area should have low ambient humidity to decrease the issues associated with seed moisture content and lots of liability |
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Temperature |
Temperature is also critical and determining seed longevity. As temperature increases the rate of seed deterioration increases at a given moisture content. Medium term storage temperatures of high value seed should be stored between 5 to 10°C. For long-term germplasm Storage temperatures below 0°C are used. |
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Harringtons rule of thumb |
A seed between five and 14% moisture content the length and time before viability declines is doubled for every 1% reduction in seed moisture content. For every 5°C reduction in storage temperature siblings and time before seed viability declines significantly is doubled. Poor quality seed or store for much shorter periods of time |
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Seed hygine |
Shorter drying times can mean seed is brought into storage at moisture content around or above the lower limit favourable to fungal growth. When such seeds is poorly cleaned, Chaffy matter can restrict air circulation through the seed leading to localised heating. As temperature increases, seed moisture content will also rise as a result of seed respiration. This favours fungal growth in the restoration from Fundy wall further raise that is MC and temperatures. |
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Seed dressing |
Many used contain oxidising compounds which can be damaging to seed in store, particularly if the seed moisture content is high |
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Pre storage |
Pre-storage stresses can also affect a seed lots store ability as well as generic variation in seed storage |
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The seed |
Can be though of as being stored from the time it reaches maximum vigour on the plant |
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