There two types of seed dormancy such as primary and secondary dormancy, these
are included to traditionally accepted classification. Seeds are released from the plant in
dormant state in the condition of primary seed dormancy, for adverse external condition6.
There are two types of primary dormancies such as exogenous and endogenous dormancy.
Germination is affected by external influences and inhibit emergence of seed. This exogenous
incident takes place due to seed coat dormancy and tissues covering the embryo are also
affected in this condition. The endogenous dormancy can be influenced with internal
condition of embryo. ABA acid level during maturation of seeds in mother plant is
responsible for primary dominance7. Although primary dormancy in the mature seed may be
absent in the period of seed dormancy due to lack of ABA, no certain relationship has been
found between ABA content and the degree of dormancy On the contrary the secondary seed
dominancy is regulated by unfavourable condition of germination of seeds. ABA
biosynthesis genes can affect seed ABA content. Thus, increasing ABA content in seeds can
cause enhance seed dormancy or delay germination. Genes, which help in biosynthesis of
ABA can affect ABA content of seeds. Thus, increasing ABA content in seeds can cause
enhance seed dormancy or delay germination. Based on a study, breaking dormancy
techniques (e.g, post-ripening, stratification, dark and smoke) are connected with variations
in ABA content during water uptake. In early developing seeds accumulation of ABA is to
induce primary dormancy and qSD7-1 also underlying gene induces the nature of dormancy
by dormancy-inducing hormone ABA in early developing seed. On the other side, GA
6 Chahtane, Hicham, Woohyun Kim, and Luis Lopez-Molina. "Primary seed dormancy: a temporally
multilayered riddle waiting to be unlocked." Journal of Experimental Botany 68, no. 4 (2017): 857-869.
7 Song, Yuan, Jiaojun Zhu, and Qiaoling Yan. "Roles of abscisic acid and gibberellins in maintaining primary
and secondary dormancy of Korean pine seeds." Journal of Forestry Research (2019): 1-12.

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