Name and natural range
POWO accepts Selenicereus megalanthus (K.Schum. ex Vaupel) Moran. The name Hylocereus megalanthus also occurs in the literature. The species is native from Colombia to Peru, and the database associates it primarily with the wet tropical biome. [2-WWW]
Fruit and reproduction
In comparative studies, fruit had yellow peel and white pulp. The fruit surface bears spines, and seeds are embedded in the pulp. The accession used by Cohen and Tel-Zur was a self-compatible tetraploid. This information applies to the material studied, with cultivars and hybrids described separately. [Cohen and Tel-Zur 2012, Cohen and Tel-Zur 2012 p. 346–347, Abirami et al. 2021 p. 2–4] [Abirami et al. 2021, Cohen and Tel-Zur 2012 p. 346–347, Abirami et al. 2021 p. 2–4]
The tetraploid genome
Selenicereus megalanthus is tetraploid, with studies reporting 2n = 4x = 44. This denotes four chromosome sets in a somatic cell. In 2025, Zaman and colleagues presented a reference genome assembly for the species. They combined long DNA reads with data on spatial chromatin contacts, DNA accessibility and gene expression. [Cohen and Tel-Zur 2012, Cohen and Tel-Zur 2012 p. 345–347, Zaman et al. 2025 p. 1, 18–22] [Zaman et al. 2025, Cohen and Tel-Zur 2012 p. 345–347, Zaman et al. 2025 p. 1, 18–22]
The final assembly of approximately 1.79 Gb was organized into eleven reference chromosomes. It represents sequences after removal of redundant haplotypes, closely similar sequence variants. The chromosome count in this representation concerns assembly organization. The tetraploid plant retains the forty-four-chromosome complement reported in the study. [Zaman et al. 2025, p. 4–5, 20]
The authors compared Selenicereus megalanthus with S. undatus and identified candidates associated with the betalain pathway and regulatory regions. Expression differences co-occurred with differences in chromatin organization and fruit colour. The study supplies a resource for breeding and mechanistic hypotheses. The authors identified candidate functions and causal relationships with pigmentation as questions for further experiments. [Zaman et al. 2025, p. 14–18]
The outcome of increasing ploidy
In Selenicereus megalanthus, increasing ploidy from four to eight sets produced a different outcome. Fruit development aborted in all octaploid lines studied. Some yield and seed parameters also deteriorated in tetraploid S. monacanthus lines. Each line therefore requires separate assessment of reproduction, growth and fruit quality. [Cohen and Tel-Zur 2012, p. 348–353]
Self-compatibility and hand pollination
Dag and Mizrahi examined fourteen yellow pitahaya clones in a covered plantation in Israel. Hand self-pollination and hand cross-pollination gave similar fruit and seed set. In this material, self-pollen was compatible, and careful transfer to the stigma increased viable seed number and fruit mass compared with spontaneous self-pollination or transfer by the bumblebees tested. Species-level self-compatibility and the effectiveness of a particular pollination method are related but distinct traits. Cultivar selection also considers flowering time and temperature conditions. [Dag and Mizrahi 2005, pp. 618–621, Table I]
The fruit after harvest
Yellow peel, pale flesh and spiny tubercles form a recognizable combination of fruit traits. Spines are removed when preparing fruit for sale. Valero and colleagues’ review highlights harvest maturity, limitation of mechanical damage and water loss, and storage temperature. Peel and flesh retain different chemical properties. Fruit-quality data describe a particular developmental stage and postharvest handling conditions. [Valero et al. 2025, pp. 2–10, Sections 2–7]
Regeneration and micrografting
Selenicereus megalanthus seedlings supplied tissue for bud regeneration in Pelah and colleagues’ study. The proximal cotyledon region responded to thidiazuron, and the resulting shoots were elongated and rooted on successive media. Moreira and colleagues examined micrografting of the species’ shoot apices onto several pitahaya rootstocks. They observed graft take and vascular connections. These are two laboratory propagation routes, with different starting material and their own assessment stages. [Pelah et al. 2002, Pelah et al. pp. 81–83; Moreira et al. pp. 3–7] [Moreira et al. 2021, Pelah et al. pp. 81–83; Moreira et al. pp. 3–7]
Related articles
Materials from the author's archive
The species also appears in Konrad Szychowski's private material archive. [Kaktologia 2009c, file p. 4]
Synonyms and names in the literature
Hylocereus megalanthus · Cereus megalanthus · Mediocactus megalanthus [2-WWW]