Priming allows some of the metabolic processes necessary for germination to occur without germination take place. In seed priming, seeds are soaked in different solutions with high osmotic potential.
This prevents the seeds from absorbing in enough water for radicle protrusion, thus suspending the seeds in the lag phase.
Seed priming has been commonly used to reduce the time between seed sowing and seedling emergence and to synchronize emergence in seed priming, the osmotic pressure and the period for which the seeds are maintained in contact with the membrane are sufficient to allow pre germinative metabolic processes to take place within the seeds up to a level limited to that immediately preceding radicle emergence.
Methods for germinating seed and inducing desiccation tolerance in seed are also provided. Preferably the semipermeable membrane is provided in the form of a tube of circular or polygonal cross-section which is rotated with the seeds on its inner surface and the solution retained between its outer surface and a further body to which the membrane is sealed in a watertight manner.
Seed priming technique has been practiced in many countries including Pakistan, China and Australia and more than thousand trials had been conducted to evaluate the performance of priming in a variety of crops. Priming technique is the need of present time to get the enhanced germination and establishment in different crops in order to utilize the soil moisture and solar radiation to a maximum extent. In this way plants would be able to complete their growth before the stresses arrive.
Osmopriming is commercially used technique for improving seed germination and vigor. It involves controlled imbibition of seeds to start the initial events of germination followed by seed drying up to its original weight. Osmopriming has many advantages including rapid and uniform emergence, improved seedling growth and better stand establishment under any environmental and soil conditions Grain yield was significantly increased in many crops subjected to priming as compared to non prime crops.
The increase in yield was 13% in case of hydro-priming alone and 26% when primed with ZnSO4 solution. So, it can be concluded that both the treatments have contributed 10 well to the total increase in yield. Final emergence, emergence index, plant height, leaf area, stove dry weight, total dry weight, individual cob weight, cob yield, cob number and number of grains per cob were observed to indicate almost same kind of response to priming treatments in increasing the final yield.
Research on priming has proved that crop seeds primed with water germinated early, root and shoot development started rapidly, grew more vigorously and seedling length was also significantly greater than non-primed seeds. It could also improve the performance of crop by alleviating the effect of salts under saline soil conditions. Soaking seed in water overnight before sowing can increase the rate of germination and emergence even in soil conditions where moisture content is very low.