Passionfruit

Origin, World Distribution & Importance
The edible commercial species of Passion fruit originated on the edges of South American rain forests in the Amazon region of Brazil and possibly in Paraguay and North Argentina. The purple passion fruit (passiflora edulis), is adapted to the coolest subtropics or to high altitudes in the tropics, while the golden passion fruit (p.edulis f. flavicarpa) is more suited to tropical lowland conditions.

Passion fruit became naturalized in most of the tropical and subtropical world covering South Africa, Hawaii, California and Florida by the end of the nineteenth century. Kenya, Sri Lanka and Fiji were naturalized with the crop by about the middle of the 20th century. In Europe, in the 17th century it was grown as an ornamental plant under glass house conditions for it's attractive flowers.

Botany
The family Passi floraceae includes 550 species in 12 genera and is represented by more fruiting species than any other plant family. The most important genus Passiflora has about 400 species which are mostly native to Tropical America and about 40 species in Asia, Australia and the South Pacific and one in Madagascar.

In most countries passion fruit production is based on caltivars of the golden passion fruit (p.edulis f. flavicarpa). The major exceptions are South Africa, Kenya and New New Zealand where production is dependent on lines of the purple passion fruit (P.edulis) and in Australia where hybrids between the two forms are exploited.

In Sri Lanka too, both purple and yellow passion fruits are grown commercially. 'Rahangala hybrid', which is a cross between P.edulis and p.edulis f. flavicarpa is recommended to be grown in the cooler regions. Yellow variety is recommended for the low country. However in the dry zone and in the intermediate zone yellow variety could be grown with supplementary irrigation. 'Hawaiian Black' which is an introduction from Australia, was evaluated under low country wet zone conditions and was later released by the Dept. of Agriculture as variety "Mani". Other introductions such as Victorian Black, E23 and Laecy evaluated under low temperature climates did not perform as well as the locally bred Rahangala Hybrid.

In Sri Lanka, 10 species Of Passiflora have been reported. These include P.quadrangularis, P.vanoloxemii, P.caerulea, P.edulis, P.flavicarpa, P.mollisima, P.ligularis, P.trifasciata. Two weed species of P.foetida & P.suberosa have been identified.

Nutrient Content of the Fruit
Nutrient composition of the two major commercial species of passion fruit are presented in Table 1. passion fruit is fair to good source of pro-vitamin A, ascorbic acid, riboflavin and niacin with also a high mineral content.

Apart from it's unique flavour (brix value range of 12-20) the comparative high acid content of the juice (2.4-%) is it's most discouraging characteristic in processing and development of value added products.

Nutrient and it's approximate composition in passion fruit caltivars per 100g edible portion.

NUTRIENT	P.edulis	P.edulis f.flavicarpa
Moisture %	85.6	84.9
Protein (g)	0.4	0.7
Fat (g)	0.1	0.2
Carbohydrate (g)	13.6	13.1
Ash (g)	0.3	0.5
Ca (mg)	3.6	3.8
P (mg)	12.5	24.6
Fe (mg)	0.2	0.4
Vitamin A (iu)	717	2410
Thiamin (mg)	trace	trace
Riboflavin (mg)	0.1	0.1
Niacin (mg)	1.5	2.2
Ascorbic acid (mg)	30	20

Culinary Use
Fresh fruits are cut in half and the succulent pulp is scooped out with a spoon for mixing with other fruits in making a salad. The extracted juice is a tasty drink. The beauty of passion fruit is that just a little pulp goes a long way. The cake icing, candy ice cream, jelly, mousses, sauces, sherbets, syrups and pies are some of the value added products made out of the fruit Tender leaves of passion fruit is also consumed as a leafy vegetable.

Other Uses
Seed of both forms of passion fruit give about 23% oil similar in properties to either sunflower or Soya bean oil and is used for domestic and industrial purposes. A cyanogenic glycoside is found in the pulp of all passion fruit but is only at an insignificant level in the ripened fruit. The glycoside passinorine can also be extracted from the dried leaves.

Yellow cultivar (Low country)
Purple cultivars (Up country)
Australian Varieties (Under tests)

Seed Extraction :
For seed extraction only fully ripened fruit should be used. Seeds are scooped pit from cut open fruits and spread over jute-hussian or gunny material. The seed is rubbed till the juice sacs burst and then washed in several changes of water. After the juice and juice sacs are removed the seed is left to ferment for 3-4 days and then washed again before drying in the shade. Immediate sowing is recommended or else storage under refrigeration packed in air tight polythene bags will preserve viability up to six months.

Nursery Practices :
Nursery should be protected from sun and rains. Width of the nursery should not exceed more than 90cm. Nursery beds should be made using 1:1:1 top soil: compost: sand mixture, spread over the bed as a layer of 10-15 cm thickness. Shallow furrows could be made by using a stick 5cm apart. Seed is preferably soaked overnight in water sown 1cm apart in shallow drains and covered with a thin layer of soil. Watering is done as and when necessary. Germination takes about 14-21 days. When the seedlings are about 20-25cm tall they are transplanted in the field one plant per each planting hole.

Seedlings can also be planted in polythene bags. Polythene sleeves 15-20cm long and 10cm in diameter are filed with a potting mixture containing 1:2:1 top soil cattle:sand when they are about 20cm tall. Once they reach 20-25cm height they can be field planted

Raising Through Cuttings:
A high yielding mother vine with good quality fruits and free of virus diseases should be selected to provide cuttings. A cutting should contain at least 3 buds and must be planted in sand beds. Cuttings may also be planted in polythene sleeves directly. Immediately after planting these should be kept inside a high humid chamber made out of bamboo and polythene.

Grafting :
This is more suitable for the Rahangala hybrid to safeguard it against collar-rot. The root stock of yellow Passion fruit is planted in polythene sleeves and the section from Rahangala hybrid is grafted using wedge or approach method of grafting.

Climatic equirements
It needs well distributed rainfall throughout the year. A suitable crop for the wet zone, however it could be grown in the intermediate and dry zones with irrigation. Major cultivation areas are Kaluthara, Clolmbo, Gampaha and Galle. Kurunagala, Kandy, Ratnapura and Babulla are other districts where it could be grown satisfactorily.

Soil :
Well drained soils are desirable. Sandy loams and clay loams are also possible soil types. Optimum pH is 6-7.5

Planting Material:
Passion fruit may be propagated by cuttings, grafts or seed. There is hardly any difference in the age at first fruiting between vegetatively propagated plants and seedlings. Since the crop is highly cross pollinated varietal purity could be maintained only by using cuttings or grafts In some instances, grafting has to be resorted to prevent the onset of root problems. Rahangala hybrid which is susceptible to collar rot damage is grafted to yellow variety as a root stock to prevent this problem.

The general practice is raise seedlings. About 175 fruits of medium size (diameter 2-2 1/2) are required to obtain one pound of dried seed. One pound contains about 800 -1000 of seed.

Land Preparation
Passion fruit is cultivated as a plantation crop. It could be also be grown in small scale as a home garden crop. When in a home garden the vine could be trained on to a fence.

Planting Season
Suitable time period is Sep-Oct. Due to uncertain climatic conditions prevailing in the country it is not possible to recommend an exact time for planting. It is always desirable to plant in to the rainy season. Time of planting does not seriously effect fruiting as the climate is ever changing.

Trellises
Passion vines are trained to grow on trellises. Trellises are in the north-south direction to minimize the shades during early morning and late evening. The construction of trellises is the most expensive item in Passion fruit cultivation. A durable and termite resistant wood should be used for the posts. Either live or dead posts may be used. Kitul is durable post used by some while concrete posts are also suitable. Live posts are used depending on their availability. Glyricidia, Kapok, Wal-ehela, Andara and bamboo are some of the live posts used. Ehen live posts are used they will have to be pruned regularly. They are planted in rows two meters apart. The height above ground for posts should be 2 1/2 meters to facilitate picking. Planting holes should be 4 1/2 meters apart along the trellises. Planting hole should be 60 x 60 x 60cm with single strand of galvanized wire (14 guage) or barbed wire drawn across the top. The wires are drawn tightly to prevent sagging and the end posts are trussed. These planting distances will give about 450 vines per acre.

Training
Young vines are trained to grow along the wire support of the trellises. Thin rope or string tied from the base of the vine to the wire could be utilized for this purpose. All lateral branches arising from the main stem are nipped off up to wire level. Two side branches arising from the main stem are bent around the top wire and allowed to grow along the in opposite directions. Lateral branches are now allowed to develop from these two side branches. Lateral branches so developed will hang down freely due to the foliage, flowers and fruits as they are formed. The growing tips of the side branches growing along the wire are broken if as they reach the next vine in the row.

Pruning
Flowers and fruits are produced on new growth. It is therefore necessary to prune the old and dead branches that have already born fruit. As passion fruit vine does not store a large amount of food reserves like grapevine, severe pruning is not recommended. A light pruning is recommended after a harvest. Virus infected vines should not be pruned as then there will be poor re-growth and severe virus symptoms. When pruning is done care should be taken to dip the pruning knives in a suitable disinfectant after each vine to prevent spread of virus diseases through the knives. Only one or two branches need to be pruned at any one instance. Branches to be pruned do not produce fruit as they trail on the groundx.

Branches are pruned leaving 3-5 nodes near it's base and the rest is cut off. One or more new flushes will develop from this stump. The new branches so formed are also trained to hang down freely. Pruning should be done after harvest with slight rains.

Weeding
Except for a space of about 60-90cm radius around the base of each vine which has to be kept clean weeded at all times, the rest of the plantation maybe allowed to have an undergrowth of grass. Most of the passion fruit can infect legume spp and it's therefore not advisable to have cover crops of legumes. Furthermore, 'Watapalu' and "Podisinghomaram' are hosts of aphid vectors which are responsible for passion fruit mottle and ringspot virus transmission. Therefore these weeds should be eliminated. Use of weedicides is not recommended as passion fruit vines are extremely susceptible to them.

Pollination
Vigorous vines begin to flower about 6 months after planting in the field. Flowers are unfortunately poor self pollinators. Carpenter and bumble bees visit the flowers at all times of the day but their numbers are not sufficient every where of the country to ensure pollination in all the flowers. Due to this reason commercial cultivations resort to hand pollination. In this method a small paint brush is used by pollinators to transfer pollen from one flower to a another. Another way is to touch the anthers and the stigmatic surface of each and every flower with thumb and forefinger as you walk along the rows. A skilled operator can pollinate about2000-3000 flowers in a day in this manner. Flowers remain open from about midday to about 3pm in the low country wet zone. Hard pollination is most effective when it is done during this period on a sunny day.

Fertilizers

Time of Application	Dry and Intermediate Zone			Wet Zone
Time of Application	Urea(g)	CSP(g)	MOP (g)	Urea (g)	CSP (g)	MOP (g)
Basal	70	105	55	60	115	55
2m after planting (if vines are weak)	70	105	55	60	115	55
6m after planting	70	105	55	60	115	55
2nd year once in 6 months	140	210	110	120	230	110
3rd year -do-	210	315	165	180	345	165
4th year -do-	280	420	220	240	460	220

Above mixture is sufficient for one plant. Top dressings should be applied 30-45 cm away from the base of each plant and lightly worked in to the soil with a fork.

Aphids :
Myzus persicae, Aphis spiraecola, A.gossyppii and A.craccivora are important as vectors. There's no severe physical damage by aphids and they do not colonize on the plant. Aphids are important as virus vectors.

Vine Girder :
A coleopteran insect 2cm in length. They have a nocturnal habit. The adults cut the stem of the fully grown vine to lay eggs. The fully grown vine is cut completely overnight. Larval stages emerge 8 days after eggs are incubated and last for 1 year. For this reason fully grown vines are selected by the adult to lay eggs.

Control
Application of a suitable insecticide mixed in a tar base around the main stem. Tar base should not be too concentrated to damage the tissues. Affected vines should be uprooted and burnt.

Stem Bulging :
Stem bulging is a severe problem in most passion fruit cultivations. Due to this disorder either the main stem or lateral branches may get swollen or bulged and blocks the vascular system. This leads to disruption of upward flow of nutrients causing poor growth and ultimate death of vine. A coleopteran beetle larva is suspected to be causing this problem. Further work is being conducted to confirm the pest.

Control
Use of a systemic insecticide (Furaden, Marshal, Reagent) after plating & before flowering may help to control this problem.

Collar Rot & Root Rot :
At nursery stage root rot may occur due to poor drainage. Pythum, Phytopthora are the casual organisms.

(A) Passion Fruit Mottle Virus :
Green and yellow mottle, leaf deformation and crinkling are the symptoms. Depending on the time of infection substantial yield losses may occur. Virus is transmitted through several species of aphids and contaminated pruning knives etc.

(B) Passion Fruit Ringspot Virus :
Characteristic symptoms of the virus are the chlorotic rings in mature and shaded leaves. The virus is a closely related strain of passion fruit mottle virus. However it produces milder symptoms than the PFMV.

(C) Cucumber Mosaic Virus :
Chlorotic mosaic and mottling are the most prominent symptoms. Infected fruit have a hard pericarp and are difficult to cut. Yield is severely reduced due to this virus. The virus is not related to passion fruit mottle virus and passion fruit ringspot virus. Spread of the virus is through different species of aphids and in contaminated pruning knives etc.

Picking
Fruits ripen 9 - 12 weeks after pollination. They should be picked once a week or twice if necessary before they drop off. Production may vary depending on various factors.

First year
Next two years
In the 4th and 5th years.

Fruits bound for the factory are packed in crates or boxes. Fruits to be sold as fresh fruit in the market has to be handled more carefully. Passion fruit juice has an excellent international market. Juice extraction is 30-33% by weight.

Unlike many other crops, the initial capital investment in passion fruit is high. Therefore the reintroduction of the subsidy scheme has to be considered seriously to encourage growers to take to this crop. Production cost per kg is Rs.12-15/- and the current price in the market is about Rs.20/- per kg.