Hylocereus sp.

Taxonomy

Kingdom : Plantae
Division : Magnoliophyta
Class : Magnoliopsida
Order : Caryophyllales
Family : Cactaceae
Subfamily : Cactoideae
Tribe : Hylocereae
Genus : Hylocereus

Species :

•  H. costaricensis (red-fleshed dragon fruit)
•  H. polyrhizus (red-fleshed dragon fruit)
•  H. undatus (white-fleshed dragon fruit)
•  H. megalanthus (sym. Selenicereus megalanthus - yellow pitaya)

Dragon fruit originated from Mexico, Central and South America. It is an easy growing crop that had been widely introduced in Mexico, Central and South America, South-East Asia, Malaysia, Thailand, Vietnam, Southern China and Israel. Dragon fruit are also known as pitaya, pitahaya, buah naga, huo long guo, thanh long, pitajaya, pitajuia or pitalia, strawberry pear in different parts of the world. The most cultivated species in the world would be white-fleshed dragon fruit (H. undatus) and r ed-fleshed dragon fruit (Hylocereus polyrhizus, H. costaricensis)(Le Bellec et al., 2006). Yellow pitaya (Selenicereus megalanthus) is famous for its sweetness but is less popular due to its thorny peel.

According to Le Bellec et al. (2007), there are 16 species of Hylocereus were cultivated for ornamental reasons and a certain few for its fruits. Its fruit is a favorite to many, particularly to people in Asia due to its exotic shape, intense colour and subtle taste. In Malaysia, dragon fruit was first introduced in 1999 in Sitiawan, Johor and Kuala Pilah. In 2007, Vietnam exported its dragon fruit to 14 countries with the total value of US$3,111,400 = mainly to Asian countries and also to European Union. Vietnam is currently the most successful grower and exporter of pitaya with production mostly grown n the Mekong Delta and Bihn Thuan province. The red-fleshed dragon fruit had good fruit quality but the fruit setting is poor and smaller in size compared to white-fleshed.

Botanical description

Dragon fruit plants are native to the tropical forest regions of Mexico, Central and South America. They are terrestrial, epiphytic plants that grow on trees anchored with aerial roots. The plant normally possessed green triangular stems and each of the stem segments is composed of three-sided wavy wings with scalloped margins which may grow to 6 metre in length. Flowers are monoecious, large (15-25 cm), bell-shaped and white in colour. Flowers are nocturnal bloomers that bloom during the early evening and close at noon the next day.

Like any other cactus plant, dragon fruit possessed an inferior ovary, numerous stamens and a long tubular style (20 cm in length and 0.5 cm in diameter), numerous stigma lobes (24 -28) that are creamy green in colour. Dragon fruit plants can have between four to six fruiting cycles in one year. It can be propagated by seed or by stem cuttings. Manual cross-pollination is usually done to obtain better fruit quality in term of fruit weight .F ruit is ovoid in shape, with a red peel covered with short triangular bracts. The scales turn from green to red when ripens while the skin peels easily. Pulp colour varies from white to red or purplish, depending on species and varieties. Numerous small edible seeds which resemble sesame seeds could be found embedded within the pulp.

Taste could be ranged from slightly sour to sweet with the soluble solids concentration of 14% during harvest time. Dragon fruit plants grow well in tropical and subtropical climates. Shading of 30% is required if the temperature went above 100 o F. Extreme sun exposure would lead to sun burnt of the vines and too much shading would result in low production and quality of fruits.

Fig 1: A mature dragon fruit plant

Fig. 2: Dragon fruits varieties