These studies were carried out to select new cultivars of crape myrtle with cold hardiness, disease resistance, and dwarfness and develop their rapid propagation method through tissue culture technique.
SKK 1, SKK 2, and SKK 3 were selected out of seedlings of Lagerstroemia indica ´Dwarf hybrid´ in 1990 at Sung Kyun Kwan University. SKK 1 and SKK 2 are a winter hardy shrub with dwarf compact and globular shrub reaching approximately 30 cm in height, pink flowers, blooming from mid June to late September and resistant to powdery mildew. This cultivar has overwintered with no protection other than natural snow cover and shown no or slight winter injury in Suwon. This cultivar has shown high resistant to powdery mildew.
All the axillary buds collected from 3-year-old seedlings of SKK 1 were successful in shoot formation when cultured on WPM (woody plant medium) supplemented with 0.5 ㎎/ℓ BAP and 0.01 ㎎/ℓ NAA. WPM containing 3.0 ㎎/ℓ BAP was the best in shoot multiplication producing an average number of 5.50 shoots. WPM and MS with BAP above 2.0 ㎎/ℓ promoted both shoot and callus production. Limited multiple shoot production was observed at 0, 0.5, 1.0 ㎎/ℓ of BAP. 75% normal rooting occured after 12 ~ 15 days culture with 1/2 GD supplemented with 0.5 ㎎/ℓ of IBA. Rooted plants were transplanted into a mixutre of peat moss and perlite (1:1, v/v) and grown under high humidity (over R. H. 90 %) for 3 weeks in the greenhouse. After hardening with progressively reduced humidity, new plants survived at ninty percent. We estimate that several thounds plants can be obtained in I year through tissue culture.
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