This in vitro study was performed to clarify several factors influencing the regeneration of bulblets and effect of chilling treatment of parent bulbs before culture at 4℃ for 4 weeks on bulb scale segments of hyacinth cv. ´Junbos´ and ´Carnegie´ in vitro. Explants were cultured or. the Murashige-Skoog´s full or half strength agar media without growth substances.
1. A comparison of bulb scales demonstrated that the number of regenerated bulblets a explant was influenced by the scale number and Murashige-Skoog´s full or half strength medium. Bulbtent growth was touch better on bulb scales 4 to 7 or 8 to 10 in full strength medium and 1 to 3 or 4 to 7 in half strength one as compared with bulb scale 1 to 3 and 8 to 10, respectively. The effect of room temperature and chilling treatment of parent bulb on the bulbets formation was small; bulblet growth, however, was favored in the bulbs of room temperature storage.
2. Both regeneration and bulblet growth were greatly promoted when the explants are taken out of the basal parts of a scale instead of the distal part. Callus and root formation occurred when the explants from bulbs which storaged in room temperature were cultured on half strength medium.
3. Optimal regeneration and bulblet growth were obtained when the explants were placed basal end upward compared with basal end down en the culture medium.
4. Number of bulblets, subsequent growth and root formation a explant were decreased by raising the temperature from 20 to 30℃, whereas callus formation was observed at 30℃.
5. No difference in bulblet regeneration was observed between light or dark condition, but bulble growth had greatly promoted in dark condition. Shoot and root formation were strongly stimulated in light condition, but explants taken out of parent bulbs which treated chilling were inhibited shoot and root formation in the case of light condition.
6. Number of bulblets a explant was outnumbered on Murashige-Skoog´s foil strength mediumcompared with half strength one, but growth of bulblet was promoted un half strength medium treatment of parent bulbs before Chilling culture was rather inhibited formation of shout and root from scale segments in vitro.
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