Vitro breeding is the first stage of potato minituber production:
Vitro plantlet production: cut fragments from virus-free plantlet and immerse into liquid medium, PH value 5.8. Each fragment contains one leaf. Place those fragment inside the clean bottle, each bottle 15~20 pieces. The bottle should be placed in environment where the temperature is 25 ℃±2 ℃, daily lightening 16~20h, light lux 1000~3000. The natural light in favorable than artificial light. After 25~30 days the plantlets will grow to certain length for another cutting. When the total plantlets reach enough quantity, move them outdoors.
Plantlet hardening: take the plantlets out and leave them in normal environment for hardening, normally 24~48 hours will be enough.
Tuberization: Using liquid medium MS+50mg/L and 100mg/L cumarin for tuberization. Temperature 25 ℃±2 ℃, dark environment. After three month, each plantlet will have 2~3 minitubers. Liquid medium should be filled from time to time, mainly by MS nutrition.