Pitaya, also called pitahaya or dragon fruit, belongs to the genus Hylocereus in the family of Cactaceae within the Caryophyllales order. Pitaya is originated principally from rainforest in tropical and subtropical areas of Latin America (probably from Mexico and Colombia) and now is one of the most economically important fruit crops cultivated worldwide. Based on traditional morphology, 15 species of Hylocereus have been identified, among which only H. undatus, H. monacanthus and H. megalanthus are commercially cultivated on a large scale for commercial production worldwide. Hylocereus spp. are diploid (2n=22) except H. megalanthus (allotetraploid, 2n=4x=44).