In Vitro Propagation

 Arya Wira Wardhana / 21025010035

In Vitro Propagation of Date Palms (Phoenix dactylifera L.)

The high consumption of date fruit has led to the cultivation of tropical dates in Indonesia since the last decade (Rahmadani et al., 2017). Date entrepreneurs hope that Indonesia can become a tropical date fruit producing country in the future, in addition to Thailand which has become a pioneer of tropical date cultivation in Southeast Asia (Apriyanti et al., 2016). The tropical dates cultivated in Thailand are KL-1 breeding results from the parent cultivars Degleet Nour and Barhee conducted by researchers at Maejo University (Apriyanti et al., 2016), while in Indonesia, date farms such as Jonggol Farm Bogor use tissue culture seeds originating from the UK. Until now, there is no laboratory in Indonesia capable of providing commercial-scale date palm tissue culture seeds.

Tissue culture seeds are clonal or the same as the parent plant. Tissue culture seeds are produced through in vitro propagation. Through in vitro propagation, mass-scale date clonal seeds can be available, especially female dates with superior characters and suitable for planting in tropical regions such as Indonesia. In vitro propagation also has advantages in terms of time and planting material requirements compared to conventional propagation. For example, in vitro propagation of dates using one tillering bud, through somatic embryogenesis (SE) techniques in suspension culture can produce 10,000 somatic embryos per liter per month, which then develop into planlets and are acclimatized into seeds with 70% survival rate.

Mass-scale in vitro propagation requires an efficient system, one of which is the use of bioreactors (Othmani et al., 2017). The utilization of bioreactors was initially for microbial cultivation. Then with the development of plant cell culture techniques, bioreactors were also used for the production of secondary metabolites from plant cells, which then developed for large-scale plant propagation (Vidal & Sánchez, 2019). The use of bioreactors allows automation in plant propagation procedures and also saves production costs (Georgiev et al., 2014).

One type of bioreactor that is widely used for plant propagation purposes is the Temporary Immersion Bioreactor (TIB) (Vidal & Sánchez, 2019). The TIB consists of three main components, namely the vessel and connecting hoses, the timer, and the pump. The bioreactor vessel is connected to a timer that regulates the duration and interval of liquid media contact with plant propagules.

As the name implies, momentary immersion, this system allows the plant propagules in the bioreactor to be in contact with the liquid medium only for a period of time. This system is considered to be the most suitable for plant propagation because it avoids continuous contact with the liquid media, which can lead to growth inhibition. Another advantage is that this system can maintain a balanced availability of nutrients and oxygen for the plants in the bioreactor without using agitation that causes damage to the plant propagules (Watt, 2012). Therefore, setting the immersion period in TIB is an important factor to create an optimal balance of nutrients and oxygen for the propagated plants. Several studies on the success of in vitro propagation of date palm plants using TIB have been reported, including for Deglet Bey cultivars (Othmani et al., 2009), Barhee (Fki et al., 2011b), Quntar (Al-Mayahi, 2015), and Mejhool and Boufeggous (Abahmane, 2020). Successful in vitro propagation of date palm in Indonesia has been reported by Saptari & Sumaryono (2018), which was carried out through somatic embryogenesis, but using explants in the form of young plants from seeds that cannot be determined whether they will produce male or female plants, and using a solid culture system.

Sources:

Abahmane L (2020). A comparative study between temporary immersion system and semi-solid cultures on shoot multiplication and plantlets production of two Moroccan date palm (Phoenix dactylifera L.) varieties in vitro. Not Sci Biol 12(2), 277-288.

Apriyanti RN, E Pujiastuti & DS Rahimah (2016). Kurma dari Gurun ke Tropis. Jakarta, Trubus Swadaya. 224p.

Perkebunan, M. (2020). Propagasi in vitro tanaman kurma (Phoenix dactylifera L.) pada bioreaktor dengan perendaman sesaat. Menara Perkebunan, 88(2), 90-99.

Rahmadani RA, S Bulkis & MA Budiman (2017). Potensi budidaya kurma di Indonesia ditinjau dari perspektif ekonomis dan ekologis. In: Prosiding Seminar Nasional ASBIS. Politeknik Negeri Banjarmasin, Banjarmasin p, 427-437

Othmani A, C Bayoudh, A Sellemi & N Drira (2017). Temporary immersion system for date palm micropropagation. In: Al-Khayri JM, SM Jain & DV Johnson (eds.), Date Palm Biotechnology Protocols Volume I: Tissue Culture Applications. New York, Springer New York. p. 239-249