Changes

*Passionfruit, granadilla (En). *Grenadille (Fr)

'''== Origin and geographical distribution''' == Passionfruit is a native of southern Brazil where it grows on the edges of rain forests. There are two distinct forms: forma ''edulis'' , the purple passionfruit, occurs in cool environments at higher altitudes, whereas forma ''flavicarpa'' , the yellow passionfruit, is at home in the tropical lowlands. The two types were distributed throughout the tropics and subtropics via Europe and Australia during the 19th Century. In South-East Asia passionfruit is mainly a home garden crop.

*A vigorous perennial but short-lived semi-woody vine, up to 15 m long. Stems glabrous, grooved, green. Tendrils axillary, spirally coiled, terete, longer than the leaves. *Leaves with stipules and petioles; stipules lanceolate, 1 cm long; petiole 2-5 cm long, glabrous, grooved above, 2 circular glands at top; blades unlobed when young, later palmately 3-lobed, cordate at base; lobes ovate-oblong, 10-15 cm x 12-25 cm, acuminate, margin with curved teeth that are glandular tipped. *Flowers solitary, axillary, fragrant, showy, 7.5-10 cm in diameter; peduncle triangular, 2-5 cm long, near the apex with 3 leafy, ovate to lanceolate bracts; calyx tubular at base, lobes 5, spreading, reflexed, yellow-green below, white above, margins with up to 4 glands, apex with a thornlike appendage; petals 5, free, white and thin, alternating with calyx lobes; corona with 2 outer rows of wavy, radiating threads, 2-3 cm long, white with purple base, and 3 inner rows of short purple-tipped papillae; stamens 5, filaments united into a tube round the gynophore for about 1 cm and then widely parted for 1 cm, anthers large, versatile, 2-celled, transverse, pale yellow, hanging downward; ovary on gynophore, ovoid, 1-locular with 3 parietal placentas, styles 3, horizontal, clavate, with longitudinal furrow, 1 cm long, stigmas reniform or cordiform, 0.5 cm in diameter. *Fruit a globose or ovoid berry, 4-12 cm × 4-7 cm, deep purple or canary yellow; exocarp hard and thin, mesocarp greenish, endocarp white. *Seeds many, attached to peg-like funiculi on the ovary wall, surrounded by yellowish aromatic pulpy/juicy edible arils; testa hard, black, 3-toothed at base.

Of the 400 known species of ''Passiflora'' L. about 50-60 bear edible fruits. In South-East Asia 5 non-edible species are endemic; about 13 edible species have been introduced. In addition to ''P. edulis'' , ''P. quadrangularis'' L. is important. Some minor introduced species are described in the chapter on minor edible fruits and nuts. Frequently, ''Passiflora'' plants are cultivated as ornamentals for their showy flowers.

Cuttings are set in steam-sterilized coarse sand and later transplanted into bags or a nursery bed. In trials with purple passionfruit, terminal cuttings with 3-4 nodes and one or two leaves gave better rooting than other types of cuttings. Application of 3000 mg/l indole butyric acid (the optimum rate) improved and speeded up rooting. Grafting is often employed to control diseases. Yellow passionfruit is used as resistant rootstock although other ''Passiflora'' species, in particular ''P. caerulea'' L., show much greater resistance to ''Phytophthora'' root rot and ''Fusarium'' collar rot. Moreover, ''P. caerulea'' is tolerant of rootknot nematode and to exposure to -1.5°C; it can be propagated from leaf and stem cuttings and is compatible with ''P. edulis'' . Wedge and whip grafts on seedling rootstocks - sometimes on rooted cuttings - are used. Micro-propagation using axillary buds gives good results.

The most important disease in the region and worldwide is brown spot ( ''Alternaria passiflorae'' and ''A. plagiata'' ) on leaves, vines and fruits. Phytophthora blight ( ''Phytophthora nicotianae'' var. ''parasitica'' ) causes the wilting of shoot tips and crown rot, particularly where water stagnates occasionally. Septoria spot, caused by the fungus ''Septoria passiflorae'' , causes extensive spotting of leaf and fruit, and occasionally of the stem. These three fungal diseases can be controlled by fortnightly sprays of copper fungicides or Ridomil. Pruning to open up the canopy for fungicide penetration is also essential. Yellow passionfruit and its hybrids are more tolerant of the diseases. Fusarium wilt is caused by the soilborne fungus ''Fusarium oxysporum'' f. sp. ''passiflorae'' ; the shoots wilt, followed by a complete collapse of the plant. Grafting to wilt-resistant yellow passionfruit rootstocks is the most practical way of control. Damping- off caused by ''Rhizoctonia solani'' and ''Pythium'' spp. can be a problem in nurseries and soils should be sterilized.

A number of virus diseases has been reported; the most widespread and serious one is woodiness. It is spread by aphids ( ''Aphis gossypii'' , ''Myzus persicae'' ) and pruning knives. Other virus diseases are ringspot from Ivory Coast, which is similar to woodiness and spread by aphids and passionfruit mosaic (PFMV-K and PFMV-MU) reported in Sarawak and other areas, which is spread by aphids and pruning knives. The most practical control is to use clean planting material, clean pruning tools and resistant hybrids, or rootstocks of yellow passionfruit.

Nematodes, especially the rootknot nematodes ( ''Meloidogyne incognita'' , ''M. javanica'' and ''M. arenaria'' ), are the most serious pest. Practical control measures are crop rotation and the use of tolerant rootstocks. The cocoa mirid ''Helopeltis clavifer'' , the passion vine bug ''Leptoglossus australis'' and the green vegetable bug ''Nezara viridula'' suck and pierce leaves and young fruits; these, together with the leaf-eating caterpillars of ''Tiracola plagiata'' , are minor pests.

Fruit flies include the oriental fruit fly ( ''Dacus dorsalis'' ), the melon fly ( ''D. cucurbitae'' ), the Mediterranean fruit fly ( ''Ceratitis capitata'' ) and the Queensland fruit fly ( ''D. tryoni'' ). Pierced young fruit shrivels and falls; later injuries cause damage which lowers the grade. Spraying insecticides may be essential if destruction of infested fruit and the use of baits do not adequately check the pest to safeguard fresh fruit export markets.

Mealy bugs ( ''Planococcus citri'' ) are usually controlled by their natural enemies ( ''Cryptolaemus montrouzieri'' ). The same applies to scales and mites which incidentally do much damage: the red scale ( ''Aonidiella aurantii'' ) and soft brown scale ( ''Coccus hesperidum'' ) as well as the red spider mite ( ''Brevipalpus papayensis'' ) and the passion vine mite ( ''Brevipalpus phoenicis'' ).

The major breeding objective is to incorporate resistance to nematodes and diseases such as Fusarium wilt and woodiness virus. Most of these traits come from the yellow passionfruit; in Queensland the purple passionfruit has been completely replaced by yellow/purple hybrids. ''P. caerulea'' , which is more tolerant of many pests, diseases and low temperature, has not yet featured in any breeding programme.