Practices to enhance germination
• seed sizing (larger seeds have shown greater viability
and vigor)
• seed priming
• pregerminated seeds
Principles of seed priming
• use of osmotic or matric forces to hold seeds in the lag
stage before redrying
• controls seed hydration to permit pregermination
metabolism but prevent radicle emergence
• results in more uniform germination in a shorter time
span
Seed priming - two methods
• osmotic seed priming
– seeds are placed in an aerated soln of PEG for 1-15 days
– seeds are dried (to near original weight)
• matrix seed priming
– PEG soln is replaced with a solid matrix (e.g., vermiculite)
– “matrix force” is created by limiting moisture
• used commercially for lettuce and pansy to overcome
thermodormancy
Pregermination
• germinated seeds are dispersed in a gel (fluid drilling)
or dried before use
• advantages: fast, uniform germination at or near 100%
• disadvantages: increased cost, seeds with a shorter shelf
life