General Morphology

Apart from one climber species (V. horovitziana), Vasconcella species are all semi-lignose shrub to tree-like species with an erect habit. The stem is medullose (contrary to the hollow stem of the Carica genus), mostly unarmed (although stipules sometimes can be converted into spines (V. stipulata)). Leaves are generally entire or lobed although heart-shaped (V. candicans) and compound palm-shaped leaves (V. palandensis) can also be found. Plants are generally dioecious although monoeciousness can be present (e.g. V. monoica, V. cundinamarcensis), and then mostly with unisexual flowers. Male inflorescences are always multi-flowered and usually long-pedunculated and paniculate. Female inflorescences are single-flowered or pauciflorous with short peduncle. Flowers are typically 5-merous with a small calyx and tubular corolla. Male flowers show diplostemonous stamens with filaments free or fused above the corolla mouth. Female flowers show an incompletely 5-locular ovary with 5 entire or branched stigmata. Fruits are baccate with crested seeds often embedded in gelatine-like sarcotesta.

Taxonomy

Genus Vasconcella has been recently (Badillo, 2000) rehabilitated as a proper genus instead of being a section of genus Carica. Due to easy natural hybridisation between species of the Vasconcella genus, proper species identification can be difficult. This can be illustrated by the existence of the hybrid V. × heilbornii with its different varieties, which have not all been described yet (Badillo, 1993). A taxonomical revision using AFLP analysis, currently under way at Ghent University, could shed another light on the taxonomical classification and the relation between species. Recently, a newly discovered species, V. palandensis (Badillo et al., 2000), was added to the genus Vasconcella putting the total number of species within the genus at 21.  

Economic Importance

In comparison with papaya (C. papaya), Vasconcella species are clearly less important. Nevertheless and due to the big variability in environments where the different species can be found, Vasconcella species are consumed, raw or prepared, by many, especially indigenous people. Babaco (Vasconcella × heilbornii cv. ‘babacó’) is gaining more importance in Ecuadorian Andean fruit production, with a production of 632 metric tons in 1996 (Soria et al. 1999). Worldwide, babaco is being cultivated on a smaller scale in countries as New Zealand, Italy, Spain and South Africa. V. cundinamarcensis is being cultivated on a commercial scale in Chile where it is sold as ababai. 

Reproductive biology

Vasconcella species generally show unisexual flowers, mostly in dioecious plants. Little studies about floral biology in Vasconcella have been realized, but pollination between different flowers probably occurs by insects. In the case of the natural hybrid Vasconcella × heilbornii fruit set occurs parthenocarpic, without the need for pollen to initiate fruit set. Nevertheless, presence of pollen can induce formation of a few viable seeds.  

Propagation and Cultivation Cycle

Vasconcella species are generally propagated by seeds although vegetative propagation by stem cuttings is possible in some species. Germination can be slow (average 30 days) and difficult, but is always improved by applying a pre-soaking of 24 h with gibberelic acid (GA₃). In the case of the natural hybrid Vasconcella × heilbornii propagation is easily realized by stem cuttings, although sometimes the few viable (cross-pollinated) seeds may be germinated using GA_3, a valuable tool to widen variability. Interspecific grafting is also possible, especially to avoid some root fungi and nematodes in susceptible species.

Seedlings (4-6 months) or rooted stem cuttings can be planted in the field, distances varying by species. Sex determination can only be effectuated at first flowering, so multiple planting (using 3 plants per pocket) with a selection at first flowering is advised. Nevertheless, in dioecious species it is necessary to maintain some male pollinators for adequate fruit set. In the case of the parthenocarpic Vasconcella × heilbornii, its propagation by cuttings results in homogeneous female fields. Flowering starts, depending on the species, some months after transplanting and the first fruits can be harvested 6 months later.

Distribution

Vasconcella species can be found in wild in a broad ecological range from dry coastal tropical lowlands (V. parviflora) over the humid subtropical forests (V. weberbaueri) to temperate regions (V. chilensis). Nevertheless, its centre of diversity is located in the Andean highlands from Colombia to Peru with a hot spot in Southern Ecuador and Northern Peru.  

Potential

Direct use of Vasconcella species consists of consumption of the fruits (rarely leaves) that can be eaten raw or prepared into juices, preserves or candies where addition of sugar results in enhanced aroma. Hybridisation of different species (natural or artificial) or collection of wild rare Vasconcella × heilbornii varieties can even widen the big pomological and organoleptic palette. Another important use of Vasconcella species is the extraction of the proteolytic enzyme complex papain, used commonly in food and pharmaceutical industry. Preliminary analyses (Scheldeman et al., 2000) of some Vasconcella species show that the activity of the dried latex, especially in V. stipulata, is up to 20 times higher than that of Carica papaya cultivars selected for their high papain activity. Resistance against some important diseases is present in a number of species. It can also be used in papaya breeding or in babaco cultivation, a species very susceptible to Fusarium fungi and Meloidogyne nematodes. Currently, research on grafting of babaco on more resistant Vasconcella species like V. weberbaueri, is carried out at INIAP in Ecuador.