The laws of various countries may restrict both the removal and the introduction of plant materials. While these regulations might seem to be unnecessary ob-stacles to the novice, they are generally based on a realistic assessment of the hazards of uncontrolled plant introduction. Permits are usually necessary for introduction, and inspection of the plant materials before and after introduction is often required. These requirements are time consuming. Transfer of plant materials within a country, however, is relatively un-restricted, so it is best to look for domestic materials before contemplating foreign introductions.

The transfer of germplasm into a region is only the first step. Some material may have to be kept in quarantine for a time. Then, it must be cared for and multiplied. If a number of varieties or kinds have been chosen for introduction, evaluation to select the best plants is desirable, and this process is usually time consuming when the plants are fruit trees. Widespread distribution and testing over a number of years is also desirable-another lengthy process.

Finally, after good new fruit varieties are available comes the problem of distributing them to the public. Not only must the mechanics of distribution be worked out, but also the producing farmer and consuming public must be educated. If this last step is not taken, trees may be willfully destroyed (if they have been distributed free of charge) or the fruit may be ignored in the marketplace.

When is the job of introducing a new fruit done? We consider the job done when 50 percent of the adult population in a country knows the fruit. By our criterion, fairly well known fruits have not been fully introduced.

Major Sources of Information

A complete list of our published sources is at the end of this book. Some of them deserve special mention. A most useful compendium was "Tanaka's Cyclopedia of Edible Plants of the World (1976)." This broadly based compendium is undoubtedly the best source of names of any kind of edible plant. Because of its breadth, it often lists little more than the scientific name, the fact of edibility, and a reference. Synonyms are often marked, but others are sometimes overlooked. Furthermore, the extensive listing cannot suggest the close relationships that exist among some entities listed as separate species. Tanaka's list contains little information concerning the frequency of use, economic importance, quality, and potential of a given fruit.

Tanaka's "Cyclopedia" relies heavily on certain regional publications to which we have referred frequently:

For Southeast Asia, Burkill's "Dictionary" (1935) is the best available source of information, although it is now somewhat out of date. "Useful Plants of the Philippines," by W. H. Brown (1951-56), was also very useful.

For India, Watt's "Dictionary of the Economic Products of India" (1893) was useful, but it may have led us into many errors because the relative importance of minor fruits was often not given. Still, we had no better source.

For the worthwhile fruits of the American tropics, we relied heavily on Uphof's "Dictionary of Economic Plants" (1968). Short to long paragraphs are supplied for each fruit, but minor species are often omitted.

For Brazil, the works by Fonseca (1954), Le Cointe (1934), and Goméz (1977) are excellent. In addition, the small book by Cavalcante (1976) is the best we know as a source of information on fruits of the Amazon basin.

For Africa, Dalziel's book (1948) is an excellent source of information. Jardin's book (1967) is more comprehensive but less informative.

The following list of institutions in the tropics might be useful in obtaining new information and specific fruits or seeds:

Brazil

Centro de Pesquisa Agropecuaria do Trópico Úmido
Caixa Postal 48
Belém
Pará Brazil

Departamento de Fitotecnia
Universidade Federal de Viçosa
36570 Viçosa, Minas Gerais
Brazil

Jardím Botanico do Rio de Janeiro
Rio de Janeiro, Gaunabara
Brazil

Jardím Botanico do Sáo Paulo
Caixa Postal 4005
Sáo Paulo, Sáo Paulo
Brazil