Effect of Scale Position and Medium Type on Bulblet Production of Hippeastrum (Hippeastrum × johnsonii) with Twin Scaling Method

Amaryllis is grown as pot outdoor plant and cut flower. Generally, this ornamental plant propagates by seed, suckers and scale cutting. Propagating by seed is not commercial and often used to produce new varieties. On the other hand, number of bulblets per mother bulb is very low under normal condition. Besides each bulb produces only 2 or 3 bulblets in a growing season and they become mature and produce flower stalk after 2 to 3 years. In some cases bulbs have no capacity to produce bulblet. Therefore, one of the strategies for shortening the growth period of the plant is to improve the traditional methods of plant propagations.
This study was done as a factorial experiment in a completely randomized design with 7 replications to evaluate the effects of medium and position of twin scales in mother bulbs on propagation of bulblets, in order to increase the rate of propagation of this ornamental plant. To measure wet and dry weight of explants, 3 replicates were used. For propagation, bulbs were cut radially into 12 equal pieces, so that each pieces were contained a part of the basal plate. To evaluate the effects of position of twin scales in mother bulbs, pieces were divided as twin scales and classified in 5 groups, so that the outermost twin scales was grouped in class 1 and the innermost twin scales was grouped in class 5. After that, the scale cuttings were dipped in 0.1 % carbendazim solution for 25 minutes and then surface water were dried using sterilized tissue paper. Media that used in this study were sand, perlite, vermiculite, Peat moss and cocopeat. For removing possible contamination from the media, all media were autoclaved for 30 minutes at 121 °C. Then twin scales cuttings were cultured in vented transparent plastic containers that filled with different media and were kept in a growth chamber at 25 °C and 16 hours lighting.Number of produced bulblet, bulblet diameter, root number, root length, fresh and dry weight of plants and browning rate of scales were recorded at the end of the experiment.
The results showed that medium and twin scale position in the mother bulb had a significant effect on the quality produced bulblet. The highest fresh weight of bulblet 1.58 g), bulblet dry weight (0.21 g) and the maximum diameter of the produced bulblet (1.5 cm) were obtained in the outermost twin scales and peat moss medium. Analysis of variance showed that the effect of culture medium on the number and length of produced leaf was significant (p