Effects of Some Chemicals on Breaking the Dormancy of Potato Tubers

Abstract

1. It has been known that the buds of potatoes are dormant for some months after their period of active growth, and the dormancy is different owing to the variety and productive area. But the buds can be induced to break dormancy by chemicals. 2. The potato growers in subtropical Taiwan are faced with certain dormant problems that chemical treatments may solve. Potatoes in the mild climates often remain dormant because of insufficient cold weather, thus making desirable treatments that hasten the sprouting of potatoes. Hence, the potato growers would have a growing season long enough for two crops one year, i. e. where the spring crop can be grown immediately upon the harvest of the fall crop and Taiwan would be supplied the seed potatoes by itself too. 3. This experiment was carried out for the purpose of detecting the effects of the chemicals and comparing the cost and facilities among treatments. 4. The chemicals such as Calcium cyanamide, Ammonium thiocyanate, Gibberellin, Atonic and Urea were tested for their capacity to shorten the rest period. 5. The resting period of potato can be successfully broken or shorten by treatment of tubers with chemicals such as Ammonium thiocyanate, calcium cyanamide and Gibberellin. 6. The effective concentration of these chemical treatments are 10% solution of Calcium cyanamide, 0.8% solution of Ammonium thiocyanate and 1 ppm solution of Gibberellin. The first two need soaking cut seed piecies for an hour and the last one, soaking cut seed piecies for two hours. 7. According to the experimental results, there are evident difference of effect between the half cut tubers and the whole ones by soaking method. 8. According to the computation of chemical cost (i. e. unit price x concentration), the ratio of treatments is A, B, C:D, E:F:G:H:I=2:12:25:5:2:3. 9. The procedure of recommended treatment is to cut freshly harvested tubers into seed pieces, soaking for 1 hour in 0.8 per cent water solution of ammonium thiocyanate, covered with sands and watering for a week to promote sprouts and then plant. 10. The effect on sprouting or bud, formation is ascribed to the CNS(superscript -), CN(superscript -), CS(superscript =), C2H4(superscript ++), C2H5(superscript ++), H2S, CH2 etc, which are somewhat toxic in chemical properties. 11. The mechanism of sprouting is unknown completely yet, the further studies of this field would be necessary and valuables.