Indigenous Strategies Used to Domesticate Plants in Brazilian Amazon Original population 281 Freq Reproductive isolation does not exist Reproductive isolation exists Selected population Selected population Derived population F1 Derived population F1 Derived population F2 Derived population F2 Average decreases until reaching same average as original population Average is maintained high (a) (b) Figure Diagram exemplifying the effect of reproductive isolation A selected sample with large fruits is removed from an original population (a) When the isolation is efficient – that is, when the new population is planted in a plot at a distance that avoids gene exchange with the original population – the new population will produce descendants with large fruits (b) When isolation is not efficient, the new population may cross with individuals from the gene group that gave rise to it and re-establish the characteristics of the original population among its descendants The more effective the reproductive isolation, the more rapidly genetic gains are achieved The Chance for Choice (Genetic Diversity) The Amazonian forest offers a grandiose biodiversity with an immense number of useful plants for domestication Considering only the fruiting species (Benza, 1980; Cavalcante, 1991; Clement, 1999; Correa, 1926–1969; Hoehne, 1946; Kerr and Clement, 1980; Kerr and Posey, 1984; Le Coint, 1947; Smith et al., 1992), one may prepare a list with more than 250 typically Amazonian species, some of which are internationally recognized, others with use restricted to Indians who extract them from the native forest, and other ‘‘little-known’’ species in general use among the civilized population that have undergone Indian influence Certainly, if one considers the vastness of Amazonia with its million km2 and its incredible variability of plant species, estimated to be between 50,000 and 60,000 for the higher plants alone (Clement et al., 1982), and the current state of economic botany in the region, it may be concluded that this list may still be increased considerably For example, in two expeditions specifically planned for collecting potential fruiting species in the Amazon region, 10 species were attained that had not yet been cataloged (Instituto Nacional de Pesquisas da Amazoˆnia/Nu´cleo Acre, 1984; Venturieri et al., 1986/1987)