Annual Reports of the War Department, 8: 231 (1908)
Report of the Philippine Commission/Report of the Director of Agriculture

Seed Preservation Experiments

Some original laboratory work has been carried on during the year in the preservation of seeds. The results already achieved promise to solve a problem which for many years has been vexing importers and handlers of seed in all hot countries where the minimum atmospheric humidity never falls below 55° and the mean normal for one-half the year approximates 85°. Hermetical sealing, while a protection to the seeds in transit, is of no assistance after arrival unless the seeds can be disposed of as soon as opened, which is of course impracticable for merchants and others handling seeds in large lots. The difficulty of preserving the vitality of seeds in this country is indicated by the fact that peas, which on arrival from the United States gave us an 84 per cent germination test, failed entirely thirty days later. Corn, cotton, and other oily seeds have deteriorated within three weeks.

The experiments described below were conducted with a lot of very fine American corn seed received here early last December, and which showed the remarkably good germination average of 95 per cent. The object of these experiments was to determine the value of the method of keeping seed in hermetically sealed jars, as compared with the method used in this bureau. Three 2 1/2-pound lots of the corn were taken at random from the shipment. One lot was placed in an ordinary metal seed cannister with a reasonably close-fitting cover. A second lot was placed in a glass jar provided with a close-fitting ground-glass stopper and at once hermetically sealed with melted paraffin. The third sample was put in a similar jar, in which had been placed an inch of coarsely broken charcoal that had just been exposed to a heat high enough to expel the moisture. While the charcoal was still warm, the corn was poured in and the whole topped off with another inch of charcoal. While still open it was exposed for thirty minutes to a gentle heat (43°C.) and then carefully sealed. This was on December 23, 1906. On May 23 of the present year (six months later) the two jars were opened, and 100 seeds taken from each, a like number from the closed cannister, and all were placed in the germinators. These tests were concluded on June 1, and we obtained from the heated jar containing the charcoal a 91 per cent germination, from that only hermetically sealed a 28, and from the cannister a 36 per cent germination. The tests were sufficient to demonstrate that hermetical sealing, unless precautions are taken to expel the very moist atmosphere, is detrimental rather than beneficial to the seeds. The unusually good showing (36 per cent) of the unprotected seeds was due in part to excellence of vitality at the start, and still more to the abnormally low reading of the hydroscope and the high, dry winds which marked the first quarter of the present year. Since the beginning of the wet season, however, the exposed corn has deteriorated more rapidly than that which was merely sealed. At the conclusion of the tests the heated corn was treated anew in the same manner and will be kept for future tests of this method. The average life of most garden and field seeds in temperate climates, without other provision than a cool, clean, dry bin, is four years, the extremes being two to ten years. These tests demonstrate the possibility of preserving all seeds even under the trying conditions which prevail in these islands. It is obvious that the importation of seeds of good quality is an indispensable factor to successful preservation, and that the cost of the method of seed preservation herein described would be great for large quantities of seeds, as they would have to be placed in small jars and much charcoal would be required. Large containers might be used, but as it would be difficult to fully exhaust the damp air and to promptly seal such containers, the danger of loss would be increased. The tests which we have made indicate that seeds from temperate countries can be preserved in the Tropics by the method described, although the use of this method on a commercial scale may not always be practicable.