Quality preservation of stored hybrid rice seeds under hermetic condition: development of a local alternative

Experiences with the implementation of the governments' Hybrid Rice Commercialization Program (HRCP) showed that hermetic storage can effectively protect the hybrid rice seeds from insect pest infestation as well as from the quality deteriorating effect of humid environments. However, the current available technology is imported and relatively expensive such that its wide use is limited especially at the level of the small hybrid rice seed producers. Hence, this study was conducted to develop a low cost alternative hermetic seed storage technology. A flexible seed storage enclosure was designed and fabricated utilizing commercially available plastic-lined sheets. It was equipped with a simple closing mechanism capable of maintaining a hermetic condition. One-year storage test trials were conducted to evaluate prototype performance in comparison with other storage practices/technologies. Test results showed that the prototype enclosure could maintain a hermetic storage condition comparably with the imported counterpart basing from the regularly monitored oxygen concentration of air and the moisture content of the stored hybrid rice seeds (PSB Rc72H) inside. Moreover, there was no insect infestation observed in the seeds stored in both the prototype and the imported enclosure throughout the 1-year storage period. In the conventional method (piled bags in open space under ambient condition), an average increase of 150 insects (a combination of dead and alive rice weevils and lesser grain borers) was observed per month per 500 g seed sample examined. For the 3 test trials conducted starting 2004, the prototype enclosure performed consistently and significantly better than the conventional practice and comparably with the imported enclosure in maintaining the viability of the stored hybrid rice seeds. Costing only P5,000/ton capacity as against P17,500/ton capacity in the imported, the locally developed enclosure hopes to enhance the capability of the local hybrid rice seed producers to store their seeds.