Effect of Kind and Plant Growth Regulator Composition on Micropropagation of Three Begonia Species

Begonia is one of the most important ornamental plants around the world. Begonia species are grown for their attractive leaves and flowers in indoor and outdoor conditions. The tissue culture technique is an alternative method for the propagation of begonia species. It can overcome the difficulties of vegetative propagation and lead to high-quality and uniform planting material under disease-free conditions irrespective of the season and weather. In begonia tissue culture, different species showed diverse responses to the medium composition, especially plant growth regulators. Also, lack of information on large scale micropropagation of begonia in Iran highlights research on optimization of begonia species propagation on in vitro culture condition. Thus, in this study the effect of plant growth regulators on shoot regeneration and proliferation of three begonia species (B. elatior‌, B. soli-mutata, and B. tiger), the impact of Auxin and sucrose on rooting of B. elatior‌and diferent pot substrate on acclimation were survived.

In this experiment, petioles of three begonia species (B. soli-mutata, B. elatior, and B. tiger) were used as explant sources. So explants were washed under tab water for 30 mins and sterilized with 1.5% sodium hypochlorite for 15 mins. After sterilization, thin Cell Layers (TCL) with 2 mm thickness were prepared from petiols and cultured in MS medium with different concentrations (0.2, 1, 2 mg/L) of kinetin (kin) or thidiazuron (TDZ) in combination with NAA (0, 0.2 mg/L). Next, the effect of auxin type (1 mg/L of IAA, IBA, and NAA) and sucrose concentration (30 and 40 g/l) on rooting of B. elatior plantlets were determined on in vitro condition. For plantlet acclimation, sand, CocoPeat perlite mixture (1:1 ratio), and Peat moss as pot substrate were evaluated.

The results showed the shoot regeneration response of begonia species to the plant growth regulators of the medium, and there was a significant difference between them in all of the species adding the Auxin to the medium increased shoot regeneration. In B. elatior and B. tiger lacking of NAA to the medium caused no shoot regeneration. Maximum shoot regeneration (100%) was achieved in B. soli-mutata species in medium containing 1 or 2 mg/L of kin and 0.2 mg/l NAA, in B. elatior at 1 or 2 mg/L of TDZ in combination with 0.2 mg/l NAA and in B. tiger at 2 mg/L of both plant growth regulator (TDZ and Kin) and 0.2 mg/l NAA.

For rooting B. elatior, MS medium containing 1 mg/L IAA plus 30 g/L sucrose was the best and favorite acclimation was acheived in cocopeat perlite mixture and peat moss pot substrate.