Viability and vigour
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Viability:

Viability refers the capacity of seed to germinate. It can be expressed by the germination percentage which indicates the number of seedlings produced by a given number of seeds.

Vigour:

Vigour of seed and seedlings is difficult to measure. Seeds with low vigour may not be able to withstand unfavourable conditions in the seedbed. The seedlings may lake the strength to emerge if the seeds are planted too deep or if the soil surface is crusted. Vigour is indicated by the higher germination percentage, high germination rate and quicker seedling growth.