A strategy is suggested for in situ conservation of crop genetic resources whereby conservation efforts are linked to rural development projects in Third World countries. We describe development projects that emphasize preservation of traditional farming systems and succeed in sustaining production by relying on the maintenance of biological and genetic diversity in these systems. Basing agricultural development efforts on indigenous knowledge, technology, and social organization can provide important guidelines for the design of cropping systems that allow lowincome farmers to produce subsistence and cash crops without dependence on external inputs and seed supplies. By incorporating landraces and wild relatives of crops into these cropping systems, major achievements in the conservation of crop genetic resources can be obtained.

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In situ conservation of crop genetic resources through maintenance of traditional farming systems

ZusammenfassungVoraussetzung und Wege, die zur Domestikation führten, werden untersucht und die Ergebnisse dieses Evolutionsprozesses diskutiert. Schon von Beginn an läßt sich eine Zweiteilung in Kulturpflanzen des großflächigen Feldbaues, die über das Saatgut vermehrt werden und bei denen die Massenauslese vorherrscht, und Kulturpflanzen des kleinflächigen Gartenbaues, bei denen Formen der vegetativen Vermehrung und Individualauslese überwiegen, verfolgen. Feldbau führt zu ausgewogenen Pflanzenbeständen mit einem guten allgemeinen Ertragspotential, ohne daß sich einzelne Merkmale oder Merkmalsgruppen durch eine überdimensionale Entwicklung auszeichnen. Gartenkultur resultiert oft in beträchtlichen Merkmalsabänderungen (allometrisches Wachstum). An drei Beispielen werden Ablauf und Ergebnisse der Domestikation untersucht.Hordeum vulgare (primäre Kulturpflanze) undPapaver somniferum (sekundäre Kulturpflanze) sind Vertreter des Feldbaus. Die Bedingungen des Feldbaus bieten günstige Voraussetzungen für eine unbewußte und indirekte Domestikation von Pflanzen, die später selbst zu Kultursippen werden können (sekundäre Kulturarten). Aber auch Unkräuter, die für eine spätere Nutzung nicht in Frage kommen, werden hier indirekt domestiziert. Unter den Bedingungen der Gartenkultur dominiert die bewußte und direkte Selektion. Als Beispiel wird hier die Domestikation vonLycopersicon esculentum untersucht.Obwohl der Ablauf der Domestikation in Abhängigkeit von den Arten recht kompliziert sein kann und eine Fülle von unterschiedlichen Formen hervorgebracht wird, gestattet das gesetzmäßige Auftreten von Gruppen spezifischer Kulturpflanzenmerkmale die Postulierung des Domestikationssyndroms. Eine Abgrenzung der Domestikationserscheinungen von ähnlichen Merkmalsentwicklungen bei kolonisierenden und ruderalen Arten wird vorgenommen.Die Kulturpflanzen sind Produkt der Kulturentwicklung der Menschheit ebenso wie die Haustiere. Parallelen in der Phänomenologie bei Kulturpflanzen und Haustieren lassen auch bei diesen das Domestikationssyndrom erkennen.Informationen bekannt und besonders die Zeit nach der Wiederentdeckung der Mendelschen Vererbungsgesetze brachte neue Erkenntnisse zur Genetik und Phylogenie der Kulturpflanzen. Der Anstoß zur weiteren Durchdringung des Domestikationsphänomens wurde durch die Untersuchungen vonEngelbrecht (1916) und besonders vonThellung (1925, 1930) gegeben.Thellung, als ausgezeichneter Kenner der Adventivflora, mußte genaue Kriterien zur Unterscheidung von Kultur-, Unkraut- und Wildpflanzen in ihren vielfältigen Wechselwirkungen entwickeln und lieferte ein zusammenfassendes Konzept (Thellung 1930), das die eigentliche Grundlage für eine Phänomenologie der globalen Erscheinungen der Domestikation bildet. VonFaegri (1981) wurde dafür der Begriff Domestikationssyndrom1 eingeführt.SummaryPreconditions for, and manners of domestication are studied and the results of this evolutionary process discussed. Already from the beginnings of domestication a differentiation of the cultivated plants into two groups is feasible-plants from larger fields which are reproduced by seeds with predominating mass selection (seed culture) and plants from gardens often propagated vegetatively being subject mainly to individual selection (±vegeculture). Seed culture results in well balanced stands of plants producing good average yields and does not lead to excessive changes in single characters or character combinations. Garden culture often results in considerable character changes (allometric growth).Three examples are given to demonstrate the course and results of domestication.Hordeum vulgare (primary crop) andPapaver somniferum (secondary crop) have been chosen as representatives for seed culture. The conditions effected from larger fields favour the unconscious and indirect domestication of plants which may become new crops (secondary crops) in later stages of this process. But also weeds which cannot be used by man are domesticated in this way. Conscious and direct selection is predominant under garden conditions. As an example, the domestication ofLycopersicon esculentum is explained.The course of domestication may be rather complicated, depends on the plant species involved and results in a huge variability of many different forms. But the evidence of groups of specific characters in cultivated plants supports the consideration of the domestication syndrome. A delimitation from colonizing and ruderal species which may show similar characters and character combinations as domesticated plants is discussed.Cultivated plants are a product of culture development in mankind, this is also true for domestic animals. Many domestication phenomena concerning cultivated plants parallel to those in domestic animals and, therefore, the domestication syndrome is also relevant for them.Краткое содержаниеРассматриваются предпосылки и пути, ведущие к доместикации и обсуждаются результаты этого эволюционного процесса. Уже с начала окультивирования можно проследить становление двух типов культурных видов: одни занимают крупные площади, размножаются посевным материалом и среди них преобладает массовый отбор; другие занимают небольшие огородные участки и среди них преобладают различные формы вегетативного размножения и индивидуальный отбор. Полеводство приводит к уравновешенным насаждениям с хорошим общим потенциалом урожайности, причём отдельные признаки или группы признаков не выделяются чрезмерным развитием. Огородные культуры часто характеризуются значительными изменениями (аллометрический рост). На примерах трёх культур исследуются процесс развития и результаты одомашнивания.Hordeum vulgare (первичный культурный вид) иPapaver somniferum (вторичный культурный вид) являются представителямн полевых культур. Условия возделования на полях дают выгодные предпосылки для непреднамеренного и косвенного одомашнивания растений, которые позднее могут сами стать культурными видами (вторичные культуры). Однако, и сорные растения, о чьём использовании в дальнейшем не может быть и речи, могут быть, таким образом, одомашнены косвенным путём. В условиях огородной культуры преобладает сознательный и прямой отбор; как пример такой селекции рассматривается доместикацияLycopersicon esculentum.Хотя процесс доместикации, в зависимости от характера вида, может быть очень сложным н привести к различным многочисленным формам, всё-таки закономерность появления групп специфических признаков культурных растений позволяет постулировать доместикационный снндром. Делается попытка отграничения доместикационных явлений от сходного развития признаков у колонизирующих и рудеральных видов.Культурные растения, как и домашние животные являются продуктом развития культуры человечества. Феноменологические параллели в одомашнивании растений и животных позволяют говорить о доместикационном синдроме и у домашних животных.

Das Domestikationssyndrom@@@The domestication syndrome@@@Доместикационный синдром

In situ Management and Domestication of Plants in Mesoamerica

Peasant agroecosystems are seen as a continuum of integrated farming units and natural ecosystems where plant gathering and crop production are actively practiced Many of these traditional agroecosystems still found throughout developing countries constitute major in situ repositories of both crop and wild plant gemzplasm. These plant resources are directly dependent upon management by human groups; thus, they have evolved in part under the influence of farming practices shaped by particular cultures. Because genetic conservation programs are more effective when preserving the ecosystems in which the resources occur, maintenance of traditional farming systems and adjacent natural ecosystems is proposed as a sensible strategy for in situ preservation of crop and wild plant genetic resources. It is here argued that preservation efforts should be linked to rural development projects that take into account the eth-nobotanical knowledge of rural people and that emphasize both food self-sufficiency as well as local resource conservation. Preservation of these traditional agroecosystems cannot be achieved when isolated from maintenance of the culture of the local people. Therefore, projects should also emphasize maintenance of cultural diversity.



Resumen: Los agroecosistemas campesinos se consideran parte de una continua integracion de unidades de produccion y ecosistemas naturales, donde la produccion y recoleccion de las cosechas son actividades diarias. Muchos de estos agrosistemas tradicionales se encuentran en paises en desarrollo y constituyen un deposito importante in situ de gemzoplasma de plantas tanto cultivadas como silvestres. Estos recursos vegetales dependen directamente del manqo por grupos humanos; por ello ban evolucionado en parte bajo la influencia de practicas agricolas de culturas particulares.



Dado que losprogramas de conservacion genetica son mas efectivos cuando se protegen los ecosistemas donde se encuentran, el mantenimiento de sistemas tradicionales de agricultura con los ecosistemas adyacentes se propone como una estrategia razonable para la preservacion in situ de los recursos geneticos agricolas y silvestres. Se argumenta aqui que los esfuerzos por preservar deben ser vinculados a los proyectos de desarrollo rural que consideran los conocimientos etnobotanicos de las poblaciones rurales y que enfatizan tanto la autosuficiencia domestica como la conservacion de los recursos a nivel local. La preservacion de estos agroecosistemas locales no puede subsistir aisla-damente del mantenimiento de las culturas locales. Es por ello que los proyectos de desarrollo tambidn deben enfatizar el mantenimiento de la diversidad cultural.

Peasant Agriculture and the Conservation of Crop and Wild Plant Resources

Different forms of management of wild, weedy, and domesticated plants carried out by the Nahua and the Mixtec in the Balsas River Basin, Mexico, are described. Along with cultivation of domesticated plants, these forms of plant management include gathering from wild populations; in situtolerance of plant individuals during clearings of natural vegetation; in situenhancement and protection of particular plants among populations of some species; as well as sowing or planting of propagules and transplantation of complete individuals of weedy and wild plants in controlled ex situenvironments. Processes of artificial selection and possible routes of domestication occurring in these forms of plant management are discussed.

Plant management among the Nahua and the Mixtec in the Balsas River Basin, Mexico : An ethnobotanical approach to the study of plant domestication

Members of Jaltomata are herbaceous perennials distributed from southwestern United States into Bolivia, and annuals in the Caribbean and Galapagos Islands. The described species do not fully represent the diversity of this genus. For example, the widespread species, J. procumbens, exhibits morphological variation in several regions of Mexico and Central America. These regions of variation may be in part the result of the plants association with humans. There is a very close match in the geographical distributions of the Tarahumara, Zapotec, Tzeltal, and Chuj cultures and the variant populations of Jaltomata in Chihuahua, Oaxaca, Chiapas (Mexico), and Huehuetenango (Guatemala), respectively. The results of the interaction of Jaltomata and humans are discussed in a general evolutionary context. Observations of Jaltomata among the Tarahumarain Chihuahua are presented as a starting point for further elucidation of progressive domestication. This encouraged weed is recognized as an intermediate between the wild and domesticate. Many vernacular names have been applied to Jaltomata some of these names are also applied to noncongeners (e.g., members of the Solanum nigrum complex).

Tilton Davis

Papers

Ethnobotany and progressive domestication ofjaltomata (solanaceae) in mexico and central america