Syzygium samarangense

The wax apple belongs to the same family Myrtaceae with guava. Syzygium spp. is mainly found in Southeast Asia (Panggabean, 1992).

Taxonomy

Kingdom: Plantae
Class: Magnoliopsida
Subclass: Rosidae
Order: Myrtales
Family: Myrtaceae
Genus: Syzygium
Species: Syzygium samarangense
Common Name: Makopa (Philippine), Wax apple, Java apple, Jambu air (Malaysia), Bell fruit (Taiwan), Jumbu (Sri Lanka)
Native: Malaysia, Indonesia, Philippines and India

General characteristics

Syzygium samarangense is more popular and commonly called wax apple. Wax apple and Malay apple are widely cultivated throughout the tropic countries. In Taiwan there are 9 native species and has more extensive commercial industry around Pingtung at the southern end of the island.

Tree

Wax apple is an evergreen, tropical fruit bearing tree, growing 5-15 meters tall with an open, wide spreading treetop. Leaves are simple, nearly sessile, and elliptic with the leaves can be up to 25 cm long . Flowers are yellowish-white with four petals and numerous stamens and the hypanthium is extended beyond ovary. Wax apple is a dense shade tree that can grow in most parts of the tropics and subtropics but it is frost and wind susceptible.

         
               
Fruit bearing tree of Syzygium samarangense
Flowers

(Source:http://virtualcrat.blogspot.com/2009/04/syzygium-samarangense-java apple.html)

Fruit

Syzygium samarangense fruit is an edible berry with oblong and bell-shaped. The colors of the fruit range from white, pale green, green, red, purple, crimson, to deep purple or even black (wild plants).The fruits are 5-12 cm in length and 1-4 seeds (1-2 cm) which have narrowed base with four fleshy calyx lobes at the apex. The fruit of wax apple are eaten fresh or processed into jams and jellies. In Malaysia , the green fruits of wax apple are eaten raw with salt or cooked as a sauce. The ripened fruit varies from light pink to dark purple red. One of the most famous wax apples in Taiwan is 'black pearl', which is highly priced and is purplish red in color. The ripened fruit varies from light pink to dark purple red. The fruits ripe about 30-40 days after anthesis, the flesh becomes white and juicy, has low acid content, sweet and crisp when fruits ripe.

     
Young fruits   Ripe fruits

(Source:http://virtualcrat.blogspot.com/2009/04/syzygium-samarangense-java apple.html)

Pollination and fruit set

The formation of flower buds does not mean early flowering (Yang et al., 1991) in Syzygium samarangense. In the dry season, wax apple commonly flowers early or late and protocols have been developed in Taiwan to trigger the flowering period. The protocols (Figure 1) need to depend on the fact that flower panicles that are borne at the tip of the shoots and in the axils of fallen leaves, and new shoot flushes for additional flowers to form (Shu et al., 1996).

 

Figure 1: Patterns of flowering and fruiting for wax apple were subjected to three different types of induction protocols ( Flowering; Harvesting; Vegetative). Induction can be a single or combination of cultural and chemical treatments.

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Inflorescence in jamun is generally borne in the axils of leaves on branchlet. Flowering starts in the first week of March until the end of April. At the second week of April, the trees are full bloom. The flowers are hermaphrodite, light yellow in color. Research was done and reported that the maximum anthesis (18.71 to 43.08%) and dehiscence were recorded between 10am and 12 noon. The fertility of the pollen is high at the beginning of the season and according to Misra and Bajpai (1975), the maximum receptivity of stigma was observed one day after anthesis. Anthesis started at about 8am and it needs 10 hours to complete and the flower opening is maximum at 5-6pm. Dehiscence of anthers started just after the opening of flowers.

Though the major flowering time for water apple and rose apple is in February-March but they are also found to bear flowers in other seasons.

According to Misra and Bajpai (1971), the flowers and fruit drop are found at three stages.

  1. The first drop takes place during bloom and this proves to be the heaviest drop as bout 52% of the flowers drop off after 4 weeks from flowering.
  2. The second drop stage starts after about 35-40 days after full bloom and there is no difference between the developing and aborting fruits.
  3. The last drop happens after 42-50 days of full bloom and continues till 15 th July.

Fruit growth and development

In jamun, Shukla (1979) reported that there was three distinct phases of fruit growth. The first phase is where the rate of growth was slow (15-52 days after fruit set), the second phase took place 52-58 days after fruit set and the rate of development was rapid and the third phase comprised comparatively slower growth with little increase in fruit weight which happened for 58-60 days after fruit set. During ripening stage, moisture content, total acidity and total reducing sugars increased and there was a steady rise in ascorbic acid and oxalic acid content prior to maturation and decreased steeply during maturation and ripening (Sarah et al.,1993). The fruit took 63 days for complete ripening from fruit set. The ripe jamun had 76 per cent edible portion and 3:1:1 pulp to seed ratio. TSS and sugars followed an increasing trend, while tannin content followed a decreasing trend during growth and development.