Manipulation of Seed Water Relations Via Osmotic Priming to Improve Germination Under Stress Conditions

Abstract

For annual crops, the time from planting to seedling establishment is a crucial phase in the production cycle. Uniformity and percentage of emergence of direct-seeded crops can have a major impact on final yield and quality, particularly for vegetables (84). Techniques of precision planting to achieve desired plant populations depend on a high probability of successful establishment for each seed planted (26). Furthermore, increasing use of expensive hybrid seed has placed additional emphasis on the performance of each seed planted. The soil environment often, however, is not conducive to rapid germination and seedling growth. Physical stresses, such as extreme temperatures, excess or deficit of water, salinity, or soil crusting; and biological stresses, including pathogens and insects, can all adversely affect germination and seedling growth. These problems are compounded by the increased susceptibility of plants to many of these stresses during germination and emergence. It is not surprising, therefore, that there have been many attempts to devise presowing treatments to improve seed performance in the field. The wide range of such treatments has been thoroughly reviewed and categorized by Heydecker and Coolbear (38).