Bulb and callus formation have been studied with scale segments and meristems (included flower bud and foliage leaf) excised from tulip bulbs, i. e. ´Merry Widow´, `Red Matador´ and ´Golden Oxford´, which were pretreated during 0, 2, 4 and 6 weeks at 4℃ before experiment. Explants from each bulbs treated by chilling treatment were placed on the Murashige-Skoog´s medium supplemented with various growth regulators. The best callus formation and growth in the bulb scale segments culture was obtained on the medium fortified with 2.0㎎/ℓ 2.4-D+5.0㎎/ℓ kinetin+5.0㎎/ℓ NAA, and 2 weeks chilling treatment was optimal period for callus formation. Callus formation among varieties was favored by the order of Red Matador, Merry Widow and Golden Oxford.
The formation and growth of bulbs regenerated from cultured meristems which were divided a half was promoted in darkness on the medium added with 0.5㎎/ℓ NAA+0.5㎎/ℓ kinetin, while light condition remarkably inhibited the formation and growth of bulb. The optimal chilling period for bulb regeneration and subsequent growth was found to be about 2 weeks in the Merry Widow and 4 weeks in the Golden Oxford and Red ´Matador. Before transplanting the produced bulbs into soil, chilling treatment of bulbs was necessary to break up dormancy for their continuously$quot; growth, but failed to grouch in the unchilled bulbs.
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