**Abstract**

Seed dormancy is a state in which seeds do not germinate despite the presence of all of the necessary conditions (temperature, humidity, oxygen, and light). It is caused by hard seed coat impermeability or a lack of supply and activity of the enzymes required for germination. The dormancy of seeds presents a practical problem of considerable economic importance. Plant growers are often interested in securing seed that will germinate soon after it is harvested. To overcome dormancy, organic material is subjected to a variety of physical and chemical pretreatments. Some plant species have both physical and internal dormancy, making it difficult to produce high-frequency healthy seedling growth, despite the fact that seed sprouting and the generation of healthy seedlings is a requirement for plant output. The Chapter is intended to present the basic information on the seed dormancy which would be of relevance to the seed growers and scientists during seed handling process. Seed dormancy is of great concern to scientists therefore it is a research area of interest. All the viable seeds have capacity to germinate if placed under suitable conditions necessary for germination. But some seeds fail to germinate for sometimes even if placed under the condition favorable for germination.

**Keywords:** seed coat, seed dormancy, seed germination, types of seed dormancy, breaking seed dormancy, factors responsible for seed dormancy

### **1. Introduction**

The history of seed is the evolution of crop cultivation for human sustenance and survival. Over time this progression had been achieved through introduction, development and release of varietal of seeds using various well-known techniques of selection, hybridization and polyploidisation. However, all these stages of seed development have little value if main aim of seed development is not achieved due to a block to the completion of germination widely known as seed dormancy. Seed dormancy is an inactive status of seed and its property that normally describes the environmental factors in which the seed would germinate. This phenomenal is determined by both seed genetics, hormones, and substantial environmental influence in seed maturation environment. However, seed dormancy could be considered simply as a block to the completion of germination of an intact viable seed under

favorable conditions [1–3]. All climatic regions have cases of seed dormancy but with varying divergent responses in adaptation to avoid hostile climate conditions for germination. The adaptation is timed to avoid unfavorable weather for germination and subsequent plant establishment and reproductive growth. All viable seeds have the ability to sprout when placed in the proper germination circumstances. However, some seeds, even when placed under ideal conditions for germination, fail to germinate. This could be due to internal reasons or a necessity for specific external conditions. During this time, the seeds' growth is halted, and they are said to be in a rest or inactive state, and this occurrence is known as seed dormancy [4]. Seed dormancy is among the least implicit phenomena in the field of seed biology particularly with the issues of clear description, unambiguous definitions and distinct types and classifications of the seed dormancy as well as the vital distinction of the different methods to terminate dormancy or induce germination and factors responsible for the mechanisms. In this chapter an attempt is made to discourse these issues in perspective of types and methods of breaking seed dormancy and factors responsible for dormancy.
