Type: Process Essays
Sample donated: Lorraine Bradley
Last updated: September 19, 2019
Seed deterioration is loss of seed quality which involves cytological, physiological, biochemical and physical changes in seeds ultimately causing the death of seed. It is one of most important causes of low productivity which is responsible for about 25% loss of annual harvested crops. (Shelar et al., 2008). The process of seed deterioration is cumulative, irreversible, degenerative and inexorable (Kapoor et al., 2011). Deterioration in seed quality may begin at any point in the plant’s development stage.
Losses in seed quality can also occur during field weathering, harvesting, processing, storage and planting. Several factors such as temperature, moisture content, relative humidity, nutrient, microorganism and other environmental factors plays an important role for causing seed deterioration. Genetic changes involve expression of deleterious or undesirable characters through gene recombination or mutation, alteration caused by pathogenic infection, aging in storage accelerated by impairment of cell structures, mitochondrial function, biochemical changes altering metabolic pathway. Cell membrane disruption and inability to retain cellular constituents occur due to the loss of membrane phospholipids (Priestley and Leopold,1983), loss of enzyme (amylase, dehydrogenase, oxidases, phospholipase, glutamic acid decarboxylase) and protein activity (Saxena and Maheshwari, 1980), reduced respiration (Woodstock et al., 1984, 1985), increases in seed leachates and free fatty acid content (Harrington, 1973).
The deterioration is manifested at the seed/seedling stage by change of seed color and deviations from the normal pattern of radicle emergence and seedling growth. Increase in the number of abnormal seedlings also indicates the extent of deterioration. The rate of deterioration varies from one species to another and also among the varieties of the same species (Jatoi et al., 2001). As seed deterioration increases, seed performance decreases progressively. Deterioration results in reduction of percentage germination percentage, weak seedlings, loss of vigor, less viability and ultimately seed death (Tilebeni and Golpayegani, 2011).
In this review paper we will discuss details about physiological & biochemical process of seed deterioration and the possibility of seed invigoration.Concept of Seed QualitySeed quality is defined as genetically pure seed with high germination percentage, free from insect, pest, disease and disease causing organisms which have a proper weight and moisture content. Quality seed ensures high seedling emergence and vigorous plant growth. The components of seed quality can be divided into four groups. (fig.