Seed Storage (31) Rubber seeds usually do not tolerate water loss below 35% on a fresh weight basis. The high seed lipid content also significantly contributes to rapid decreases in viability after harvest and rapidly reduces seed life span. When seeds will be immediately planted after harvest, they can be packed in permeable cotton bags and stored for short periods.
Seeds high in initial physiological potential and adequate moisture content (35%, fresh weight basis) exhibit high storability. However, when stored at moisture contents below 30%, viability is lost quicly, especially when exposed to low temperatures.
In contrast, if seed storage for periods up to six months is planned, they can be packed in plastic bags (65 cm long x 45 cm wide x 0.5 to 0.7 thick). Seeds are packed as soon as they are harvested and the bag volume should not be filled beyond 2/3 of its capacity (approximately 5 kg of seeds). The bags must be carefully closed since maintaining an empty space in the upper third of the bag where it is perforated with six holes, 1 mm diameter to allow gas exchange and keep the seeds at an adequate moisture content. The bags are placed in a vertical position throughout the storage period.
(32) Several other factors affect seed performance during storage besides moisture content and temperature. In general, storage potential is closely related to initial seed viability and vigor. This was demonstrated many times such as the results of Cicero et al. (1986) showed in Table 2. Seeds with 88% initial germination had greater storability when kept in a laboratory environment which maintained high seed moisture content. In addition, seed storage at low temperature with a Captan treatment rapidly deteriorated.
(33) Recalcitrant seeds are prone to storage microorganisms such as Aspergillus and Penicillium species that usually contribute to increased seed deterioration. However, fungicide treatment failed to provide seed protection during storage against these mircroorganisms as seen in table 3.
(34) In contrast, data in Table 4 show the effects of packaging material on seed conservation during storage. Plastic bags which are resistant to moisture movement between seeds and their surrounding environment maintained the highest germination for rubber tree seeds.