Seed Dormancy: Induction, Maintenance and Seed Technology Approaches to Break Dormancy

Dormancy is the major cause of erratic germination, patchy emergence and uneven seedling establishment in the field. These traits are exceedingly undesirable in crop production as future phases of growth and development are strongly linked to uniform seedling development at early growth phases. Variations in maturation time, and difficulty in managing abiotic and biotic stresses during pre- and postharvest are common consequences of uneven germination and seedling emergence. Minimizing this negative impact of dormancy in a seed lot is the major concern of all seed production companies. Generally, mature seeds show some considerable dormancy during which embryo growth is halted momentarily because one or more internal and external stimuli for growth resumption is/are absent. If the inhibition of seed germination is solely due to insufficient or complete absence of external signals, then the seed is in a state of quiescence. Otherwise, if linked to internal factors, then the seed is in a state of dormancy. Induction, maintenance, and release of dormancy are therefore related to Seed-dependent factors such as morphology, hormones, state of embryo maturity at seed dispersal and chemical inhibitors. This chapter focuses on species-dependent methods currently used to break dormancy, reduce germination time and improve emergence and seedling establishment.