The optimum explanting time of shoot from mother plant, surface sterilizing method of shoot tips, and effective concentration of plant growth regulators and minerals on medium were investigated for in vitro micropropagation of yooza (Citrus junos Sieb. et Tanaka).
1. The favorable method for sterilizing shoot tip was; the shoot tips were sterilized in 1.0% sodium hypochlorite solution added with 0.01 Tween 20 for 10 to 15 min., and rinsed 4 times with steriled distilled water and subsequently dipped in 70% ethanol for 1 sec., and washed sufficiently with steriled distilled water.
2. Optimum explanting time of shoot from mother plant was the early of May in the both of adult and young trees.
3. Optimum concentration of plant growth regulators supplemented to MS medium for callus induction was 0.5∼0.1㎎/ℓ of 2, 4-D or 1.0㎎/ℓ of NAA.
4. Shoot and roots were initiated from callus in 1/2 strength Murashige and Skoog (MS) medium.
5. For shoot initiation, 1/2 strength MS medium supplemented with IBA 0.5㎎/ℓ plus BA 0.5 ㎎/ℓ was most effective.
6. For root initiation, IBA 0.5㎎/ℓ alone, IBA 0.5㎎/ℓ plus BA 0.1㎎/ℓ, IBA 0.5㎎/ℓ plus BA 0.5㎎/ℓ respectively was relatively effective.
7. Consequently, 1/2 strength MS medium supplemented with IBA 0.5㎎/ℓ plus BA 0.5㎎/ℓ was most effective for in vitro plant regeneration from callus induced from shoot tip in yooza.
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