The most important factor for the success of plantation is readily availability of quality seeds. In favorable climatic conditions with optimum moisture and temperature most of the tree species germinate quickly and in unfavorable conditions some degree of seed dormancy occurs. There are various kinds of dormancy occur in trees species such as; exogenous dormancy due to hard seed coat, seed coat impermeable to water, presences of chemical; endogenous dormancy due to immaturity of embryo, oxidation and presence of inhibitors; and double dormancy which include both seed coat and embryo dormancy. In most of tropical tree seeds, physical dormancy occurred because of hard seed coat whereas temperate trees seeds mainly have physiological dormancy. There are various methods to deal with different kinds of dormancy i.e. through Scarification, Stratification, Chemical, Biological, and Irradiation methods.(I) Scarification which is done in hard seed coated species such as Acacia spp., Albizia lebbeck, Cassia spp., Santalum album, Terminalia arjuna etc. Mechanical scarification and concentrated Hâ‚‚SOâ‚„ have been widely used to improve germination of several hard seed species, but the level of seed coat thickness among various species is the reason for different responses to all treatments. (II) Stratification is done to remove physiological and morphological dormancy. Most of the Conifers generally have physiological dormancy, stratification for 0-5ËšC for 60-70 days is better to overcome this kind of dormancy. (III) Chemical methods include use of growth regulator and chemicals for dormancy breaking. Growth hormones such as gibberellins, IAA and Kinetin etc. are mostly associated with seed germination and seedling physiology. Among all growth regulators GA₃ is most commonly used for germination enhancement @ 100-200 ppm for 1-2 h in most of the species. KNO₃ is important chemical for germination enhancement in many species such as Acacia nilotica, Melia azedarach etc. (IV) Biological method by passing through digestive tracts of animals like seeds of Acacia senegal and (V) Irradiation method irradiate seeds with like x-rays, light rays, gamma rays etc. So, breaking seed dormancy is necessary for seed germination enhancement in nursery.

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