This study was conducted to develop a rapid mass propagation method of new yellow variegated cultivar of korean Forsythia, Forsythia koreana ´Seoul Gold´, through an axillary bud culture. The obtained results are as follows:
New yellow variegated cultivar, Forsythia koreana ´Seoul Gold´ is a bud mutant from a Korean-native F. koreana. It has a gold yellow band, covering about one - half the width of the leaves along the margin. Axillary buds collected from glasshouse-grown potted plants produced shoots when cultured on a WPM supplemented with 0.5 ㎎/ℓ BAP and 0.01 ㎎/ℓ NAA. Shoots multiplied most on a WPM containing 3.0 ㎎/ℓ BAP, producing 8.0 shoots from a single shoot explant. Multiple shoot development was most effective in the second node, while shoot tip had the shortest shoot length and the smallest shoot number. Leaves were no effective on multiple shoot formation. Greater than 90% of the shoots rooted after 12 ∼ 15 days culture in all the media tested (1/2 GD + IBA 0.5 ㎎/ℓ, 1/2 GD control, 1/2 MS + 0.5 ㎎/ℓ, 1/2 MS control, and GD control).
Rooted plants were transplanted into a mixture of peat moss and perlite (1:1, v/v) and grown under high humidity for 3 weeks in the glasshouse.
After hardening under progressively reduced humidity, 90% of the new plants survived. Several thousands of micropropagated new yellow variegated cultivar, F. koreana ´Seoul Gold´, were grown in containers; 3 months after rooting, most plants were 30 ㎝ tall. Results indicate that micropropagation of new yellow variegated cultivar, F. koreana ´Seoul Gold´, has a high potential for the use in commercial industry.
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