Germination and Keeping Quality of Parsnip Seeds Under Various Conditions

Abstract

1. In germination tests conducted shortly after harvest, well ripened brown seeds give better germination than green seeds. 2. The germination of green seeds can be improved through artificial drying at 60⚬ C. in vacuo for four days. 3. There is no definite optimum germination temperature for freshly harvested seeds, constant and alternating temperatures between 20⚬ 27⚬ being equally favorable. 4. With increasing age, parsnip seeds stored under unfavorable conditions require a temperature alternation of 15⚬-25⚬ C. for germination, while seeds stored under conditions favorable to the retention of vitality germinate best at 15⚬ C. 5. Stored in paper bags at room temperature, ripe parsnip seeds lose their vitality at a rate of 20 per cent during the first two years and approximately 60 per cent during three years of storage, when the moisture content of air-dry seeds is 6.33 per cent in the beginning and 5.6 per cent at the end of the storage period. 6. There are various ways by which the keeping quality of seeds may be improved. At a temperature of 5⚬-7⚬ C. in an ice box the seeds keep for a considerably longer period, although their moisture content increases in the moist atmosphere of an ice box to more than1.5 times that of seeds stored at room temperature (9.1 as compared with 5.6 per cent). 7. If the seeds are dried carefully and thoroughly, either for twenty-four hours in vacuo at 72⚬ C. or for four to six hours at 90⚬ C.,to a moisture content of 0.40 to 1.7 per cent, their viability remains high even if they are stored at room temperature. To insure a continuous low moisture content, seeds treated in this way have to be kept in air-tight storage. The "critical moisture content" of parsnip seeds lies somewhat below 6.13 per cent. 8. Seeds which are not artificially dried cannot be stored under exclusion of air without losing their vitality very rapidly. Although a low storage temperature retards the death rate of unaerated moist seeds, it does not remove the injurious effect of lack of ventilation. 9. In advising practical storage methods for parsnip seeds, three methods of storing are suggested: (1) Storage at ice box temperature(approximately 5⚬ C.) with frequent stirring of the seeds to secure good ventilation; with this way of handling, even a very high atmospheric humidity is of little importance to the keeping quality of the seed. (2) When a higher storage temperature has to be used, a thorough drying of the seeds (90⚬ C. for four to six hours) and a subsequent air-tight storage in sealed containers insure good keeping quality. (3) Optimum keeping quality should be obtained where artificially dried seeds are stored air-tight at low temperatures.