The length of the dormant period of potato tubers varies depending on the variety. The dormant period can be as long as more than 3 months and as short as about 1 to 2 months. Seed potatoes that have not completed dormancy will have difficulty germinating after sowing, seedlings will emerge slowly, and may even rot, which is extremely detrimental to production. In order for seed potatoes to release dormancy during storage and germinate early, some techniques need to be used to break seed potato dormancy.
In production, the plant growth regulators used to break tuber dormancy mainly include gibberellins and auxins (including naphthalene acetic acid, indole acetic acid, thiourea, chlorohydrin, etc.). Since the concentration of auxins is difficult to control, soaking seeds in thiourea or ethanol for too long will affect seed germination. Therefore, gibberellins (mainly gibberellic acid) are used most in production.
Soaking potato seed potatoes with gibberellic acid can break the dormant period of seed potatoes and generally allow them to germinate 5 to 7 days earlier. First, select disease-free seed potatoes, put them in 0.5 mg/L gibberellic acid solution, soak them for 5 to 10 minutes, then take them out and place them in a place with a temperature of about 20°C for germination.
Three methods for treating potato seed potatoes with gibberellins:
- Soak seeds before sowing
Cut medium and late-maturing spring potato varieties into pieces before sowing, soak the seed potatoes in 1.0 mg/L gibberellin solution for 10 to 15 minutes, take them out, dry them in the shade, and place them on a germination bed. They will germinate after 4 to 5 days. It is necessary to pay attention to the concentration of gibberellin. If it is too high, the buds will germinate quickly, but the buds will be thin; gibberellin with a concentration of 0.5 mg/L is also effective, but the soaking time is longer, usually 1 hour. If it exceeds 30°C, it will easily rot. This method can be used for early, medium and late maturing varieties of autumn potatoes.
- Spray before sowing
For medium and late maturing spring potato varieties, 10~20 mg/L gibberellin solution can be sprayed on potato tubers during autumn sowing until the surface is moist. Spray 3 times with an interval of about 8 hours.
- Spray before harvesting
Spraying 50kg of 100mg/L gibberellin solution per acre on the plants 10 to 30 days before potato harvest can promote the germination of potato tubers, with more and neat buds and less rot rate. The effect is more pronounced in cold and wet climates that are unfavorable to germination.
It should be noted that the application concentration of gibberellins should not be too high, otherwise it will have an inhibitory effect or make the seedlings too slender; the seed soaking time should not be too long, and it should not be germinated at high temperatures, otherwise it will cause the plants to grow too long.