The Domestication of Fruit and Nut Tree Species in Vanuatu, Oceania - Indigenous Fruit Trees in the Tropics: Domestication, Utilization and Commercialization - page 133

a coconut palm leaflet. They are very popular and this trade could be further
developed, just like the trade in Canarium , as an export industry. In Papua
New Guinea the fruits of T. kaernbachii are used in a similar way and it might
be interesting to introduce this species elsewhere in Melanesia and in Polynesia.
The fruit of this species is the largest among the Combretaceae.
7.4 Discussion
There are numerous indigenous fruit and nut trees species in Oceania and most
of them are still in the process of being domesticated. The domestication
process can be summarized as follows:
1. Selection of a wild genotype or a seedling from a cultivated form. The
domesticator identifies a productive morphotype and tests its fruits or nuts. If
the quality is acceptable, a volunteer plant (a seedling found under the mother
tree) or a fruit is collected. For very few species, such as breadfruit, clonal
propagation is possible .
2. Improvement of the environment. The soil where the young plant is planted
is well prepared. Unlike the mother plant, the seedling is planted in a
considerably modified environment. The soil is loosened and weeds and bush
around it are cleared off. This improved environment contributes directly to the
ennobled development of the selected genotype, its canopy development and
fruiting aptitude.
3. Improvement of the population composed of well-established selected
seedlings which are going to intercross in a modified environment. In
Melanesia, many cultivars of breadfruit, for example, are simply clones of
edible wild forms and a few putative wild forms are probably feral plants that
escaped from cultivation, or survivors found in secondary forests in locations
where villages existed in the past. Some cultivars are also clones of hybrids
between wild forms and feral or cultivated plants. The most prolific and
vigorous trees are always selected, and vigour is often associated with
heterozygosity and/or a heterotic effect. Over the long term, the continuous
selection of the largest, sweetest, least fibrous fruits, the largest nuts or the
softest shells, trees with prolific production, or those that are early- or late-
maturing has led to in situ improvement of the species. This is a form of
recurrent selection with very long cycles. Very often the person who starts the
selection process may not be the one who will reap the benefits of the genetic
improvement.
All cultivated species now present several variable morphotypes, to which
farmers assign particular names in vernacular languages. The number of
distinct cultivars varies according to species and location. For example, some
communities in northern Vanuatu can distinguish up to 100 different
morphotypes of breadfruit (Walter, 1989) and 20 of Canarium spp. and/or
Tahitian chestnut ( Inocarpus fagifer ). When reproduction includes sexual
recombination, the plant's genes are systematically redistributed in each
generation cycle, which makes it difficult to achieve identical multiplication of