Seed enhancements may be defined as post-harvest treatments that improve germination or seedling growth, or facilitate the delivery of seeds and other materials required at the time of sowing. This definition includes three general areas of enhancements: pre-sowing hydration treatments (priming), coating technologies and seed conditioning. Pre-sowing hydration treatments include non-controlled water uptake systems (methods in which water is freely available and not restricted by the environment) and controlled systems (methods that regulate seed moisture content preventing the completion of germination). Three techniques are used for controlled water uptake: priming with solutions or with solid particulate systems or by controlled hydration with water. These priming techniques will be discussed in this paper with reference to methodology, protocol optimization, drying and storage. Coating technologies include pelleting and film coating, and coatings may serve as delivery systems. Seed conditioning equipment upgrades seed quality by physical criteria. Integration of these methods can be performed, and a system is described to upgrade seed quality in Brassica that combines hydration, coating and conditioning. Upgrading is achieved by detecting sinapine leakage from nonviable seeds in a coating material surrounding the seeds. Seed-coat permeability directly influences leakage rate, and seeds of many species have a semipermeable layer. The semipermeable layer restricts solute diffusion through the seed coat, while water movement is not impeded. Opportunities for future seed enhancement research and development are highlighted.

Emergence percentage, photosynthesis, and growth in the laboratory, and field performance were compared in four seed sizes of four varieties of soybeans [Glycine max (L.) Merrill]. The three largest seed fractions exhibited superior emergence percentages and greater cotyledonary and unifoliolate leaf area in the laboratory. However, the smallest seed size exhibited higher photosynthetic rates. The three largest seed sizes showed greater overall emergence percentage, leaf area, and height in the field. Further, the three largest sizes yielded significantly more than did the small size when grown at uniform populations. Although the yields were significantly different, neither the percentage size distribution of the harvested seeds nor the seed quality was affected by the size of the seeds used to plant that plot.

Seed corn (Zea mays L.) ears harvested at seed moisture contents greater than 400 g H2O kg−1 fresh wt. (fw) are sensitive to rapid, high‐temperature (45–50 °C) drying, but tolerant to low‐temperature drying. A preconditioning process that precludes this injury without major moisture loss was used to study the nature of the drying damage and the role of soluble sugars in membrane stabilization during drying of two seed corn hybrids. Ears were harvested at moisture contents of 550, 450, and 400 g H2O kg−1 fw, and preconditioned at 35 °C for 6 to 48 h before drying at 50 °C. Seed germination was correlated with leachate conductivity (r = −0.79) and sugar leakage (r = −0.80) after different times of preconditioning indicating the involvement of membrane function in the damage caused by high temperature drying. Total soluble‐sugar concentration decreased during preconditioning with no significant change individual monosaccharide content. The percentage composition of sucrose and a larger oligosaccharide, raffinose, increased significantly during preconditioning. The high correlations between raffinose/sucrose and warm germination, conductivity, and sugar leakage (r = 0.83, −0.80, and −0.71 for A632, and 0.89, −0.78, and −0.79 for B73, respectively) indicates the added effect of raffinose on induced protection. These results suggest that soluble‐sugar compositional relationships rather than absolute content may play an important role in membrane stabilization. The presence of raffinose at certain levels also may be a key factor in protecting maturing seeds from high temperature drying damage. The results also indicate that the transition from desiccation intolerance to tolerance is metabolic and not necessarily related to moisture loss.

the effects of drying temperatures on corn seed quality. Can

Production of high quality seed corn (Zea mays L.) would be facilitated by the harvesting of the seed at a kernel maturity which is highly correlated with maximum seedling vigor. This study attempted to correlate several kernel maturity indices with measures of seedling vigor in a maturing seed corn crop.Hybrid seed samples were taken from two field locations of production of maternal parents ‘A632’, ‘Va26’, ‘B73’, and ‘Mo17’ from 35 days to 98 days after silking. Kernel maturity indices evaluated were: 1) fresh kernel respiration rates, 2) black layer development, 3) moisture percentage, and 4) dry weight accumulation. After drying, the seed was grown on moistened, rolled paper towels in the dark for seven days at 25 C. Vigor measurements included germination percentage, shoot dry weight, and root dry weight. Although germination percentages were high over all harvest dates, both shoot and root dry weight were highly dependent on date of harvest. Distinct vigor maxima and minima were noted, and the first and last sample dates never corresponded to maximum shoot and root dry weight. Dates of maximum vigor and kernel maturity patterns were specific for each hybrid. Maximum kernel dry weight was correlated with maximum shoot and root dry weight, and the range of kernel moisture percentage corresponding to initial attainment of maximum kernel dry weight was small.