The presence of dormancy in a seed is the most important characteristic feature, because of this character, seeds remain viable for many years. Most of the seeds are unable to germinate just after dispersal. They germinate after sometime. The time between the maturation and germination of seed is known as the dormancy period. The state of inhibited germination as a result of internal causes is usually called dormancy. This seed dormancy is of considerable advantage to the plant which helps in adverse environmental conditions. The embryo remains inactive in this period and all the growth processes suspended temporarily. There are three main basic reasons of dormancy of seed, they are: