MICROPROPAGATION AND GROWTH REGULATION OF TULBAGHIA VIOLACEA 'SILVER LACE'

Tulbaghia violacea L. is a perennial bulbous plant with a high ornamental potential for nursery growers. We aim to develop a micropropagation protocol for variegated Tulbaghia violacea 'Silver Lace', using appropriate growth regulators and cultural methods which will retain the variegated phenotype. Flowers and shoots, were used as primary explants for establishment of cultures using modified MS medium, supplemented with: Ml; 0.25 mg/L BAP, M2; 1 mg/L BAP, M3; 3 mg/L BAP and M4 5 mg/L Kinetin. All media contained 0.1 mg/L NAA. Explants were readily established on M3 and M4 media with flower explants producing the greatest number of viable variegated shoots. Micropropagation rates increased significantly after sub-culture of explants to media M3 and M4, however only 32-35% of explants retained the variegated phenotype and there was no significant difference between the media tested. The effects of wounding were investigated on shoot production and on plant variegation. Explants were wounded by two methods, a) transverse cut of at the base of the shoot and b) longitudinal cut at the base of the shoot and cultured on M3 and M4. The overall micropropagation rate was 2.4 and 5.2 for the transverse and longitudinal cuts respectively and production of variegated explants increased significantly from 35 to 71% in explants wounded by a longitudinal cut. Results from this experiment show that wounding may play an important role in the retention of explant of variegation. Experiments are ongoing to assess the value of using liquid culture to increase the micropropagation rates and the production of variegated shoots at a commercial scale.