RESUMO
BACKGROUND: Studies of domestication enables a better understanding of human cultures, landscape changes according to peoples' purposes, and evolutionary consequences of human actions on biodiversity. This review aimed at discussing concepts, hypotheses, and current trends in studies of domestication of plants, using examples of cases studied in regions of Mesoamerica and Brazil. We analyzed trends of ethnobiological studies contributing to document processes of domestication and to establish criteria for biodiversity conservation based on traditional ecological knowledge. METHODS: Based on reviewing our own and other authors' studies we analyzed management patterns and evolutionary trends associated to domestication occurring at plant populations and landscape levels. Particularly, we systematized information documenting: ethnobotanical aspects about plant management and artificial selection mechanisms, morphological consequences of plant management, population genetics of wild and managed plant populations, trends of change in reproduction systems of plants associated to management, and other ecological and physiological aspects influenced by management and domestication. RESULTS: Based on the analysis of study cases of 20 native species of herbs, shrubs and trees we identified similar criteria of artificial selection in different cultural contexts of Mexico and Brazil. Similar evolutionary trends were also identified in morphology (selection in favor of gigantism of useful and correlated parts); organoleptic characteristics such as taste, toxicity, color, texture; reproductive biology, mainly breeding system, phenological changes, and population genetics aspects, maintenance or increasing of genetic diversity in managed populations, high gene flow with wild relatives and low structure maintained by artificial selection. Our review is a first attempt to unify research methods for analyzing a high diversity of processes. Further research should emphasize deeper analyses of contrasting and diverse cultural and ecological contexts for a better understanding of evolution under incipient processes of domestication. CONCLUSION: Higher research effort is particularly required in Brazil, where studies on this topic are scarcer than in Mexico but where diversity of human cultures managing their also high plant resources diversity offer high potential for documenting the diversity of mechanisms of artificial selection and evolutionary trends. Comparisons and evaluations of incipient domestication in the regions studied as well as the Andean area would significantly contribute to understanding origins and diffusion of the experience of managing and domesticating plants.
Assuntos
Agricultura/métodos , Etnobotânica , Biodiversidade , Brasil , Conservação dos Recursos Naturais , Produtos Agrícolas , MéxicoRESUMO
Plant domestication is an evolutionary process guided by human groups who modify the landscape for their needs. The objective of this study was to evaluate the phenotypic variations between populations of Spondias tuberosa Arruda (umbuzeiro) when subjected to different local landscape management strategies. The influence of the landscape management system on these populations was evaluated in five identified regional units (mountains, base of mountains, pastures, cultivated areas and home gardens). Ten individuals were randomly selected from each region and subjected to morphological and chemical fruit analysis. The diversity index, based on Simpson's index, was determined for the different populations. We then evaluated the morphological differences between the individual fruits from the distinct landscape areas. We observed no significant differences in morphological diversity between the areas studied. Our data suggest that the umbuzeiro specimens in this region may be in the process of incipient domestication.
Assuntos
Agricultura/métodos , Anacardiaceae/classificação , Anacardiaceae/genética , Anacardiaceae/crescimento & desenvolvimento , Anacardiaceae/fisiologia , Brasil , Conservação dos Recursos Naturais , Meio Ambiente , Variação Genética , FenótipoRESUMO
The present work seeks to quantify the knowledge of two rural communities in the semi-arid region of the state of Pernambuco (northeastern Brazil) concerning two species of native medicinal plants: "aroeira do sertão", Myracrodruon urundeuva (Engl.) Fr. All. (Anacardiaceae) and "angico", Anadenanthera colubrina (Vell.) Brenan (Mimosaceae). Semi-structured interviews were carried out, combined with a checklist/inventory method, which yielded different indexes for quantifying knowledge and use of these species. In addition, the reliability of local knowledge was tested using analytical techniques to determine actual tannin concentrations. Although both communities possess knowledge concerning these two species, one of them stood out in terms of the diversity of information presented (P < 0.05), a difference that may be related to its lower degree of modernization. In general, older people had a greater variety of information about these plants, although both men and women demonstrated similar knowledge. Of the 101 people interviewed in Riachão, 85% stated that they knew of uses for both species studied; in Ameixas, of the 55 interviewees, 63% responded that they knew of uses for Myracrodruon urundeuva, and 45% knew of uses for Anadenanthera colubrina. A total of 97 different uses were reported by all informants for the two species studied. Of these, 62 were mentioned in only a single community, confirming our hypothesis of differences in knowledge between them. Informants from both communities knew of a great variety of uses for these plants as well as a number of different collection techniques. We expected that knowledge about the two species would differ in relation to both gender and age, but this was only true for one of the communities. Greater concentrations of tannins were expected to be found consistently in the tree bark, but experimental data demonstrated that tannin concentrations can vary among plant parts during the year.