Seed germination and in vitro propagation of pitahaya (Hylocereus undatus)

Abstract

Hylocereus undatus, commonly known as dragon fruit or pitahaya, is a species of climbing cactus belonging to the Cactaceae family. This cultivar has gained worldwide popularity due to its striking appearance, sweet and exotic flavor. Furthermore, antioxidant, vitamin, and mineral content makes it a valuable crop of great economic importance in various tropical and subtropical regions of the world. Therefore, the aim of this research was to evaluate different protocols for seed disinfection and in vitro propagation of Hylocereus undatus. Seeds were extracted from ripe fruits and disinfected with 50 % (v/v) NaClO and 70 % (v/v) ethanol, with varying immersion times. For germination, the disinfected seeds were planted in 50 % Murashige and Skoog (MS) medium supplemented with 30 g/L of sucrose and 2.5 g/L of phytagel. Stem, hypocotyl, and cotyledon explants were subsequently
used for shoot induction, along with growth regulators such
as naphthaleneacetic acid (NAA), benzylaminopurine (BAP),
and 2,4-dichlorophenoxyacetic acid (2,4-D) at concentrations of 0 and 2 mg/L. In the disinfection phase, the results showed that protocol 2, which used 50 % (v/v) NaClO for 10 minutes of immersion, induced 100 % disinfection and 85 % germination. For shoot induction, treatments supplemented with naphthaleneacetic acid and benzylaminopurine were observed to induce shoot formation in stem explants. The highest number of shoots (15.11) was obtained with 2 mg/L of BAP. Finally, in vitro plant acclimation to greenhouse conditions resulted in a 90 % survival rate using peat moss and perlite as substrates. These findings highlight the effectiveness of the protocol designed for the in vitro propagation of Hylocereus undatus, potentially contributing to commercial production.