Plant regeneration from cotyledon, hypocotyl, and leaf of plantlet through in vitro culture, which derived from somatic embryo induced from immature ovule, was attempted in order to make mass-production system of virus-free plants having same genotype with mother plant in yooza (Citrus junos Sieb. et Tanaka).
1. Callus induction from cotyledon was highly occurred in Murashige and Tucker´s (MT) medium containing 2, 4-D 0.1 or 1.0㎎/ℓ, but shoots were not differentiated from callus, whereas only roots were formed from callus. Shoot and root were directly formed from cotyledon in MT medium containing BAP 1.0 or 3.0㎎/ℓ, and the growth was also significantly better than that of other treatments.
2. Callus induction from hypocotyl was highly occurred in MT medium containing 2, 4-D 0.1 or 1.0㎎/ℓ, but organ formation was very poor. Vigorous shoots and roots formed directly from hypocotyl in the MT medium containing kinetin 3.0㎎/ℓ or BAP 3.0㎎/ℓ.
3. Callus induction from leaf was high in the medium containing 2, 4-D as other explants, and plant regeneration from leaf was higher achieved than that from other explants, when auxin was added on the MT medium, but no organ formation observed in kinetin and BAP treatment, regardless of concentration.
4. When malt extract was added on the medium, organ formation was inhibited rather than that in the malt extract free-medium in any incubated tissue.
5. Cotyledon as well as hypocotyl were desirable as explant source for plant organ formation.
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