Introduction of flora from the old world and causes of crop marginalization

Contents - Previous - Next

Degree of marginalization of american plants
Causes of the marginalization of useful plants
Conclusion

The effects of the diffusion of American crops such as the potato, maize, sunflower and tomato in Europe, and of the extensive use of agricultural products derived from other American plants such as cotton, cocoa and cochineal berry are fairly well documented. What are not so well known are the repercussions of the introduction into America of crops and products from other parts of the world. In this chapter, an attempt will be made to analyse the marginalization of native plants in Latin America, especially in face of introduced European agricultural crops, products and methods and ideas as well as their subsequent local development.

Several problems arise when studying the neglect of native crops that resulted from the conquest of the greater part of America. These include:

· difficulties of a conceptual nature concerning terms such as cultivated plant and marginalization;
· the destruction of pre-Hispanic vestiges which may have shown the stage reached in agriculture when the Europeans arrived on the new continent (the accounts given by the conquistadores, the main ones to have been handed down to posterity, are lacking in objectivity);
· the variety of events and contradictory processes which have occurred on the Latin American subcontinent over the last 500 years and the difficulty of conducting a general analysis of the phenomenon;
· the size of Latin America and its natural, cultural and historical diversity, which requires a regionalized approach to understanding the marginalization of plants.

From an economic point of view, the fact that various previously neglected plants are being used more intensively holds great promise now that both modem society and traditional communities are requiring additional products to meet their numerous needs. The study of traditional agriculture is providing very valuable information that serves to reinforce the modem trend of seeking sustainable agricultural development. This research also benefits biology and agronomy by contributing knowledge on the evolutionary process under domestication, the adaptation of crops, production techniques and agricultural development.

There is much illustrative information on the large number of plants that were being used in some American areas when the Europeans arrived and on those that are being used nowadays in traditional rural communities. In the "Códice florentino", 724 plants are mentioned of which only 382 have been identified botanically. At the moment, one Totanac community is using 325 species of a total of 482. The Seris, Tarahumaras and Huastecos are using 75, 137 and 201 species, respectively, for food. This indicates that the traditional communities, including the indigenous American communities at the time of the Europeans' arrival, used several hundred plants from their environment, while the populations with a heavy Western influence used much fewer.

A distinction should be made between: wild plants, which appear spontaneously in natural ecosystems; plants that appear spontaneously on tilled ground and generally in areas disturbed by human beings; cultivated plants, which are the product of human toil and dedication; and domesticated plants, which have undergone profound genetic transformations as a result of domestication and which are generally unable to survive unless cared for by humans. The plants used by American societies fit into all of the categories mentioned.

If this classification is accepted, it would be appropriate to include among wild plants almost all the plant diversity existing when the Europeans arrived, while cultivated plants would comprise at least the majority of those indicated by Vavilov (1931) and other authors as crops originating from America - between 49 and 104 species for Mesoamerica and 45 for the Andean region. The number of species actually domesticated by the indigenous peoples before the arrival of Christopher Columbus was lower, as many of the species mentioned earlier were only in the process of domestication while some should be considered wild and a high number spontaneous on tilled ground.

It is known that traditional societies frequently use and conserve a variety of cultivars of one single species. For this reason, the phenomenon of marginalization should not be reduced to the displacement of botanical species but should also include the neglect of cultivars and traditional varieties within the same species through replacement by others or by a small number of variants or forms of that same species. This is usually referred to as genetic erosion. If this point of view is accepted, it would follow that, on account of the European conquest, the extent of the marginalization of American plants has perhaps been somewhat wider than could be evaluated at the species level only.

The basis for an assessment of the marginalization of useful plants should be a comparison of the area's inventory of its flora as well as of the useful plants indicated in the codices and early studies carried out by Europeans in America, on the one hand, with those plants currently used in traditional communities and in commercial agricultural production, on the other. The close relationship existing between the diversity of flora, useful plants and native crops must always be kept in mind.

In traditional societies, especially, plants are not cultivated individually but in complex agronomic ecosystems. Although one or more plants are the central agricultural objective (maize, beans, gourd, potato, peach-palm or pejibaye), many others are also used: therefore, in order to evaluate the displacement of useful plants brought about by the conquest, it would also be necessary to consider the damage suffered by pre-Hispanic agricultural systems and the marginalization of many plants that were used in earlier times as a result of the destruction of hydraulic infrastructure, the annihilation of local populations, the development of livestock rearing, etc.

Degree of marginalization of American plants

From the literature on the exploration, conquest and colonization of America by the Iberian countries, it is not clear whether the introduced crops that displaced the existing ones were imposed immediately and extensively. Moreover, in the sixteenth and seventeenth centuries there does not seem to have been a profound transformation of American agriculture. Indeed, according to recent studies, no proof has been found to suggest that the production of plants such as amaranth, clearly intended for religious and idolatrous uses and therefore contrary to the ideas that were being imposed, stopped as a result of specific prohibitions.

The introduction of plants from the old continent began in 1493 with the second voyage of Christopher Columbus. For many, the Antilles served as a centre of adaptation and dispersion. Hernán Cortés, in the Cuarta carta de relación a Carlos V, requested that every ship "should carry a quantity of plants and should not set sail without them because it will be a great thing for the population and its perpetuation". The introduction of plants and animals established the basis for colonization.

With a few exceptions (banana, sugar cane, mango and others), the Spanish brought Mediterranean crops which could only adapt to the high temperate zones of America. These were densely populated areas which were supplied with Spanish products cultivated in adjoining regions.

Monasteries served as acclimatization centres for European plants which, in some cases, expanded further and were grown in the new producer areas. One advantage of the introduced crops was that they could be used in cold areas where mild frosts were recorded in the winter periods. Many crops of the Old World were maintained on small plots such as those of the religious orders who, through their monasteries, were the first to introduce agriculture based on non-American species. The indigenous communities maintained this tradition in their family fruit and vegetable gardens and on their cultivated land. Several colonial historical sources explained the ecological and social alterations brought about by the introduction of new crops and livestock into the indigenous agriculture and economy. It was customary and a very common practice among the indigenous populations to mix introduced crops with native crops. Consequently, the biodiversity and abiotic elements of the ecosystem were protected.

In the documentation on tributes, encomiendas, allotments and haciendas, only isolated cases are mentioned in which the seeds of crops from the Old World were handed over. In colonies directed from the Iberian Peninsular, we know of attempts by the Spanish crown to introduce such crops as wheat, barley, rye, olive trees and sugar cane. Except for the latter case, which was an important economic stimulus, these crops seemed to fare no better than American products. It actually proved more efficient and convenient to pay homage with indigenous products than with exotic products.

Wheat, for example, was sown on maize fields or close to land given over to livestock. In the Caribbean or on tropical lowlands, it prospered only occasionally while, in areas with a long agricultural tradition, such as the Andean high plateau and Mesoamerica, it did not manage to displace maize -which it did, however, on borderlands inhabited by hunters and gatherers. These zones were found in semi-arid or arid areas where the climate was favourable but labour was difficult to find, since such zones were sparsely populated and their inhabitants were nomads who lacked an agricultural tradition. Hence. for the most part these areas were populated with indigenous people from other regions and Europeans. The olive- and vine-growing areas were similar in character. These crops, like many from the Old World, were introduced by religious orders in the middle of the sixteenth century. Some crops that were important for the Spanish economy were imported into America in later periods with negative results for the mother country, as occurred in New Spain with indigo, flax and hemp which were unable to become established.

Most of the crop displacement seems to have taken place in modern times, especially since the second half of the nineteenth century, by which time the former Spanish and Portuguese colonies were independent countries and capitalism and commercial agriculture were expanding.

It is interesting to note that 500 years after the discovery of America, in the pre-Columbian traditional agricultural regions of the highlands (Mesoamerica and the Andean region), European crops do not display the qualities normally attributed to them and by virtue of which their use has been advocated for centuries. On the contrary, their failure to adjust to the climate, their susceptibility to pests and diseases, the competition with native products, their insufficient quality, low acceptance by the aboriginal populations and, more recently, their poor compatibility with industrial products are factors which have discouraged their exploitation, thereby emphasizing the marginal or non-existent role frequently played by exotic plants in local production.

The situation is very different in the sparsely populated arid and semi-arid borderlands where colonization principally began in the seventeenth century. Here, livestock production as well as, to a lesser extent, the cultivation of European cereals and - although only exceptionally - vines and other introduced crops, were converted into major activities, thus resulting in a countryside similar to that of the Iberian Peninsula.

The history of agriculture in the tropical areas after the conquest consists in the struggle of pre-Hispanic crops and the traditional agricultural systems - especially slash-and-burn clearing against livestock production and plantations, regardless of whether the commercial crops were native or introduced (sugar cane, cotton, prickly pear for cochineal, and then coffee, banana, henequen, tropical fruits, stimulants, etc.).

No substantial advances are evident in the development of agricultural technology as regards the methods and instruments that arrived in America from the end of the fifteenth to the middle of the sixteenth century. From the time of colonization to the present, both the mining centres and the urban centres have demanded predominantly American products. In American countries with a strong indigenous influence there may be vast expanses devoted to introduced crops, but native flora and crops also play a considerable role.

In areas that formerly had dense Indian populations, there is in the best of cases a syncretism between the pre-Hispanic agricultural traditions and those of Iberia, resulting in a mixture of products of local and European origin for use in food, clothing, medicine and ceremonies.

Causes of the marginalization of useful plants

Marginalization is a complex phenomenon that requires a multidisciplinary analysis: however, its general causes are biological, agricultural, cultural and economic in nature.

Biological and agricultural causes
Agricultural methods. Plough and draught animals were the most revolutionary introductions to agriculture, since they enabled it to expand through wide fertile areas of heavy soils such as El Bajío and many valleys of northern Mexico. New irrigation facilities also appeared.

Another fundamental innovation was the introduction of livestock. With European colonization and extensive interbreeding, vast areas based on the practice of hunting and gathering were transformed into agricultural-livestock zones, which most certainly caused the marginalization of plants that were gathered in earlier times by hunters who were in large measure exterminated.

The introduction of many plants was accompanied by a technology to facilitate their cultivation, either because of the specific agricultural practices they required or because their care demanded less time. These qualities were generally not found in native crops, which needed a great deal of attention and were labour-intensive.

The American Indians liked to experiment and use many plants and they therefore tended towards mixed cultivation. The result was that several introduced crops were combined with native crops, especially on family vegetable plots. The Indians also favoured ecological complementarily. in other words cultivation in different environments.

Length of life cycle. Owing to the climatic differences with the Iberian Peninsula, in the majority of the different regions of America it was impossible to adapt perennial species, in spite of the repeated efforts to introduce the vine, olive tree, fruit-trees and other arboreal species. Instead, in various areas and from early times green vegetables and other short-cycle herbaceous plants introduced by the Europeans prospered. This allowed the sufficient cultivation - especially during the cold season - of such crops which were of limited availability in America. It was possible to introduce without too much difficulty small-grain cereals, rice and other annual crops with an average cycle.

Adaptation of introduced crops. The distribution and unit yield of the world's current major crops show that domesticated plants frequently reach their optimum yield in a place that is very different from its origin. It is sufficient to consider the development in Latin America of crops such as coffee, banana, citrus fruit, soya and various grasses. This phenomenon can be explained by the initial absence of pests and diseases in the place where they have been introduced. The neglect of American native plants became more acute in the nineteenth century and was basically due to socio-economic causes and, to a lesser extent, the failure of varieties originally introduced to adapt. Only when these plants had developed under domestication were they able to expand extensively. Proof of this is the existence of specific American eco-types of many of the plants introduced, which have played a fundamental role in production and in local plant improvement programmes.

Major obstacles had to be overcome to introduce crops even into areas very similar to those of southern Spain, a region which was of fundamental importance in the transfer of a Mediterranean agriculture to America. There were enormous difficulties in acclimatizing barley, wheat, vine, olives and fruit-trees in locations with a climate very similar to that of Andalusia and Estremadura or southern Portugal, whose biological and social conditions were very favourable. When New Spain became independent, European crops were already well established in this part of America.

Nowadays, chemical synthesis has displaced some natural products: synthetic vanilla has caused a reduction in the cultivation of vanilla, for instance, while synthetic anilines have replaced erythoxyline, derived from campeachy wood.

Cultural causes
The pre-Columbian indigenous societies had managed to meet a certain amount of their requirements in food, clothing, health and tools, etc., so the adoption of some European products and the consequent abandonment of native products took a long time. Even at present it frequently happens that indigenous communities mainly resort to native plants, while they grow introduced plants or rear livestock for the market or for food on special occasions. Rather than displacing the use of American products, the adoption of European products has complemented them in gastronomy, medicine and religious ceremonies, for example, which are generally the result of cultural syncretism.

The colours and flavours or textures of the Old World's plants satisfied the indigenous communities' demands. In several parts of America, vegetables introduced by the Europeans were assimilated very easily. Indeed, certain non-American plants contained colours with a symbolic importance and. moreover, coincided with the food habits of the indigenous peoples.

An important cultural factor was the role of the African cultures and their effect on agriculture: the slave trade brought crops of African and Asian origin. for instance.

Catholicism was integrated into various Amerindian religious currents, which explains why exotic and native plants were grown to meet the requirements of the indigenous Catholic ritual. Religious orders encouraged the introduction of crops; the use of American magical plants or amulets was prohibited and they were replaced by European ones. Utilizing Old World plants, using horses, carrying a sword or dressing in a European way were cultural signs which conferred prestige. These uses and habits mainly influenced the indigenous nobility, such as local rulers or traders.

Economic causes
Most frequently, the reasons for the neglect of a native or introduced species that was ecologically and agriculturally adapted to a region were socio-economic. Underdevelopment was one of the main reasons for the existence of many neglected species on the subcontinent. The low purchasing power of the vast majority of the population diminished the market of many products, which subsequently disappeared or were marginalized. This does not mean that economic development necessarily leads to a more diversified agriculture. Rather, with the economic improvement of a region or country, or with their entry on to the international market, some marginalized plants, whether native or introduced, may be converted into major crops (prickly pear for the cochineal berry, indigo, cereals, fruit-trees, henequen, etc.). The transformation of traditional agriculture into commercial agriculture generally results in the specialization of production, with the cultivation or utilization of many species being abandoned. The paradox of underdevelopment is that it prevents certain crops from finding an adequate market, which is why they are kept by the Indians to meet possible personal or collective needs. However, with economic development some of these neglected plants do find a market, or their market is widened, while many others disappear and various crops that were previously important may even become marginal owing to the monetarization and proletarianization of the peasant farmers.

Economic and agricultural transformations are related to factors such as considerable changes in the size and distribution of the population: the development of infrastructure (especially communication routes, irrigation and produce storage systems); land occupancy, the marketing of products and agricultural inputs; industrialization; the financing of production; and consumption patterns.

It is known that after the conquest there was a collapse and partial relocation of the population in Latin America, which certainly brought about changes in the plants used. The demographic upset was not only quantitative, as it particularly affected the indigenous aristocracy who were the repository of the culture and, therefore, of the use of many plants for specific purposes such as medicines, rituals and decoration. Until the seventeenth century, the population made no significant recovery and colonial cities developed in old indigenous regions as well as around congregations, missions and mining centres. Until then, there was an accelerated development in introduced crops, above al I to meet the demands of the population of European and mixed origin.

A key to understanding the slow adoption of a European lifestyle in America is to consider the low number of the white population, compared with the millions of the native population. The former is estimated to have been 849 000 around 1650, while the indigenous population is calculated to have been 10035000 and the black, mixed and mulatto population 1 527 000.

The conquest and colonization resulted in the partial destruction of many hydraulic works, medicinal plant gardens, schools, etc., which possibly caused the marginalization of many plants without their immediate replacement by other European plants. The building of infrastructure was only significant at the end of the sixteenth century. In the area of botany, Francisco Hernandez collected and studied Mexican plants between 1570 and 1577. Under the Bourbons, science and technology received a great impetus and Spanish botanical expeditions to America were organized, although these seem to have had little effect on agriculture and the plants used.

Changes in land occupancy are fundamental to an understanding of the marginalization or expansion of certain plants. However, it is known that the motive behind the expropriation of indigenous land was generally not to turn it over to exotic crops, but rather to oblige payment for the hire of native products or services and to channel labour forcibly towards mining. livestock rearing, building, etc. However, the Spanish and Portuguese crowns were obliged, because of their own interests, to limit the expropriation of indigenous communities' lands and, in doing so, they protected agricultural traditions while also halting the marginalization of native plants.

The expansion of livestock rearing l ed to very profound changes in land use. It brought fodder and crops such as wheat. barley and rice. A great deal of lend was originally devoted to livestock rearing and then to the farming of introduced plants. These changes are well documented in both South and North America as well as. to a lesser extent, in the Caribbean.

The marketing, industrialization and financing of agriculture were limited during colonial settlement, so they did not have much influence on the choice of plants grown. Tributes, taxes and religious contributions certainly had an effect on the changes in cultivation patterns, particularly when they were demanded in coin. However, payment in kind with native products was generally permitted.

The policy of the Spanish and Portuguese crowns on colonization made it obligatory by royal decree for colonists to take plants from their region to the New World (Santa Fe de Bogota, Puebla de los Angeles, Huancayo etc. were places in America where this type of obligatory introduction was practiced). Cities were thus created which Imitated as far as possible those of the Iberian Peninsula.

Conclusion

The situations presented here are the most manifest; through the period of discovery, conquest and colonization, Latin America experienced an evident case of agricultural cross-breeding, although each region responded in different ways to the arrival of plants from the Old World. One only has to reflect on the elimination of indigenous populations; epidemics and famine are well documented for the three main vice-royalties: New Granada. Peru and New Spain. European agronomic culture did not develop in major sectors of the indigenous population, except in small areas where there was no culture with an agricultural tradition or in those where the population accepted the changes with ease.

TABLE 2 Plants marginalized as a result of Old World crops

Species Common names
ARID AND TEMPERATE ZONES OF NORTH AMERICA
Asimina triloba Papaw, pawpaw
Cyrtocarpa procera Chupadilla, jocose
Diospyros virginiana Persimmon, kaki
Gossypium hoped Arizona cotton
Helianthus tuberosus Jerusalem artichoke
Myrtillocactus geometrizans Garambullo
Opuntia spp. Prickly pear, tuna
Panicum sonorum Arrocillo
Phellopterus montanus Gamote, pastinaca de monte
Photinia arbutifolia Holy fruit (fruta santa)
Ribes grossularia Gooseberny
TROPICAL. LOWLANDS AND THE CARIBBEAN
Aniba roseodora Palo rosa
Annona cherimola Cherimoya, cherimoyer, chirimoyer, custard apple
Annona muricata Soursop, guanabana, graviola
Annona reticulata Bullock's heart, sugar apple, custard apple
Calathea allouia Topinambour, topitampo, topi-tamboo
Dioscorea trifida Cush-cush, yampi yam
Helicornia bihai Platanillo or "wild banana"
Malpighia glabra Acerola, azarole
Maranta arundinacea Arrowroot, Bermuda arrowroot
Monstera deliciosa Ceriman, cheeseplant
Pachyrhizus erosus Yam bean, manioc bean, jicama
Platonia insignia Bacury, bakuri guiana orange
Pouteria campechiana Canistel
Xanthosoma sagittifolium Tannia, tania, yautia, new cocoyam
MESOAMERICA  
Amaranthus hypochondriacus Prince's feather
Bixa orellana Annato, arnatto, roucou, achiote, bixa
Byrsonima crassifolia Nance, golden spoon
Casimiroa edulis White sapote, Mexican, casimiro apple, matasano apple
Crescentia alata Cirian, tecomate
Cucurbita ficifolia Cidra, sidra, chilacayote, Malabar gourd
Dahlia excelsa Dahlia
Diospyros digyna Black sapote, Indian ebony persimmon
Indigofera suffruticosa Anil, indigo plant
Manilkara zapota Sapodilla (plum), chiku, chicle, naseberry, beef apple
Phaseolus acutifolius Tepary bean
Pouteria sapota Sapote, marmalade plum, mammee zapote
Spondias mombin Yellow mombin, jobo, taperebá
ANDEAN REGION
Arracacia xanthorrhiza Arracacha, apio, Peruvian parsnip
Bertholletia excelsa Brazil nut, Pará nut
Canna edulis Achira, Queensland arrowroot, tous-les-mois
Fragaria chiloensis Pine strawberry, pineapple strawberry
Lepidium meyenii Maca
Oxalis tuberosa Oca
Passiflora ligularis Sweet granadilla
Solanum phureja Andean potato (papa andina)
Tropaeolum tuberosum Mashwa, añu
Ullucus tuberosus Ullucu, oca quina

The process of marginalization in the nineteenth century was no clearer; the agricultural pattern remained constant in spite of the collapse of the dominant population sector. The independent Latin American countries depended on other nations looking for commercial products; the United Kingdom, France, Germany and the United States dominated the agricultural sector. The plants cultivated were those demanded by the growth of modernization, which caused a greater specialization but left room nevertheless for American crops of which the agricultural landscape was previously composed.

Faced with the current ecological crisis, it is not surprising that the countries advocating reductionist policies in the handling of germplasm, which are the same countries that brought about the marginalization of crops, should be the first to want to restore biodiversity.

Consideration is now given to how several crops were wiped out, mainly in areas where populations and indigenous cultures disappeared; it is worrying that, in the tropics, deserts or temperate zones, not even the peasant framers have any recollection of certain plants that were once cultivated.

Bibliography

Anderson, E. 1952. Plants. man and life. Boston, Little, Brown.

Archibald, R.1978. The economic aspects of the California missions. Washington, DC. Academy of American Franciscan History.

CATIE-GTZ. 1979. Los recursos genéticos de las plantas cultivadas de América Central. Turrialba, Costa Rica, CATIE-GTZ.

Chevalier, C. 1985 . La formación de los latifundios en México Mexico City, Fondo de Cultura Económica.

Crosby, A.W. 1972. The Columbian exchange biological and cultural consequences of 1492. Westport, USA, Greenwood.

Cuevas, S.J.A. 1991. Definición, aprovechamiento y conservación de los recursos fitogenéticos en una comunidad indigene totonaca. Centro de Botánica. Colegio de Postgraduados Chapingo, Mexico. (thesis)

Delgado Salinas, H.A. 1988. Variation, taxonomy, domestication and germplasm potentialities in Phaseolus coccineus. In P. Gepts, ed. Genetic resources of Phaseolus beans p. 441 -463. Dordrecht, the Netherlands, Kluwer Academic.

De Solano, F.1977. Tierra y sociedad en el reino de Guatemala. Guatemala, Editorial Universitaria.

Dressler, R. 1953. The pre-Columbian cultivated plants of Mexico. Bot. Mus. Leafl. Harv. Univ., 16(6): 116- 172.

Estrella, E. 1988. El pan de América etnohistoria de los alimentos aborígenes en el Ecuador. Quito, Ediciones Abya-Yala.

García, M.J. 1959. Lo que España Ilevó a América. Madrid, Taurus.

Gibson, C. 1967. Tlaxcala ala in the sixteenth century. Stanford, USA, University of California Press.

Gibson, C. 1977. España en América. Barcelona, Grijalvo.

Gibson, C. 1987. LOS aztecas bajo el domino español (1519-1810). Mexico City, Siglo XXI.

Gómez Pompa, A. 1985. LOS recursos bióticos de México (Reflexiones). Jalapa, Guatemala, INIREB.

Hernández, X.E. 1985. Biologia agricola. Mexico City, CECSA.

Hernández, X.E. & Zárate, M.A. 1961. Agricultura tradicional y conservación de recursos genéticos in situ. In R. Ortega, G. Palomino, G. Castillo, V. Gonzalez & M. Livera, eds. Avances en el estudio de recursos fitogenéticos de Mexico p. 7-28. Chapingo, Mexico, SOMEFI.

Hirshberg, J. 1978. La fundación de puebla de los angeles - mito realidad. Historia mexicana 28(2): 185-223.

León, J. 1987. Botánica de los cultivos tropicales. San José, Costa Rica, lICA.

Martínez, J.L. 1984. Pasojeros de Indias. Madrid, Alianza Universidad.

Miranda, J. 1980. El tributo indígena en la Nuevu Espuña durante el siglo XVI 2nd ed. Mexico City' El Colcgio de México.

Moreno, T.A. 1968. Geografia económica de México (Siglo XVI). Mexico City, El Colegio de México.

Patiño, V.M. 1969. Plantas cultivadas y animales domésticos en América Equinoccial. Tomo IV: Plantas introducidas. Cali, Colombia, Imprenta Departamental.

Patiño, V.M. 1980. Los recursos naturules de Colombia aproximación y retrospectivas Santa Fe de Bogotá, Colombia, Carlos Valencia Editores.

Rindos, D. 1984. The origins of agriculture. An evolutionary perspective. Orlando, Fla., USA, Academic.

Rojas, T. I 983. Evolución histórica de las plantas cultivadas en las chinampas de la cuenca de México. In T. Rojas, ed. La agricultura chinampera. Compilación hístorica. p. 181-213. Chapingo, Mexico, UACH.

Schmit, V. & Debouck, D.G. 1991. Observations on the origin of Phaseolus polyanthus Greeman Econ.. Bot. 45(3): 345-364.

Serrera, R.M. 1974. Cultivo y manufactura de lino cáñamo en Nueva España (1777- 1800). Seville, Spain, Publicaciones de la Escuela de Estudios Hispano-Americanos de Sevilla No. 120.

Toscano, S. 1946. Una empresa renacentista de España: la introducción de cultivos y animales domésticos euroasiáticos en México. Cuadernos americanos 25: 143 - 158.

Vavilov, N.1.1931. Mexico and Central America as the principle centre of origin of cultivated plants in the New World. Bull. Appl. Bot. Genet Plant Breed., 26: 135-199.

Vavilov, N.1. 1949-1951). The origin, variation, immunity and the breeding of cultivated plants. Waltham. Chronica Botanica 131(16): 1366.


Contents - Previous - Next