| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Systematics and Phytogeography |
Rancho Santa Ana Botanic Garden, Claremont, California 91711 USA
Received for publication December 15, 2003. Accepted for publication July 2, 2004.
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMETHODS AND MATERIALSRESULTS AND DISCUSSIONLITERATURE CITED |
|---|
Key Words: archaethnobotany • Bayesian analysis • crop origins • Opuntia • Opuntia ficus-indica
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODS AND MATERIALSRESULTS AND DISCUSSIONLITERATURE CITED |
|---|
. Opuntioid cacti are recognized as ideal crops for arid regimes (Felger, 1979
; Russell and Felker, 1987
) because Opuntia ficus-indica is extremely efficient at converting water into biomass (Kluge and Ting, 1978
). Opuntia ficus-indica, one of several long-domesticated cactus species (Casas et al., 1997
; Casas and Barbera, 2002
), is the most widespread and economically important of these cactus crops (Nobel, 2002
; Nobel et al., 2002
), as important as corn and tequila agave in the agricultural economy of modern Mexico (Barrientos, 1966
). The facile introgression of Opuntia is very well documented; this genus is among the most interspecifically promiscuous plants, perhaps rivaled only by Quercus L. in this regard (Benson and Walkington, 1965
; Grant and Grant, 1971b
, 1979
; Felger, 1979
; Baker and Pinkava, 1987
, 1999
; Griffith, 2001a
, b
, 2003
; Pinkava, 2002
; among others). The relative ease of vegetative propagation of Opuntia is demonstrated by its occasional clonal dominance of certain areas (Grant and Grant, 1971a
; Mandujano et al., 1996
). This aspect of Opuntia marks it as a noxious weed in some places (Dodd, 1936
; Nobel, 1994
). This ease of clonal propagation was probably not lost on the very early human population of the New World. Evidence exists for the use of Opuntia as human food at least 9000 yr before the present (Kiesling, 1998
) or even as early as 12 000 yr ago (Callen, 1967
), probably before cultivation (Ostolaza, 1994
).
|
; Inglese et al., 2002
). Important tuna-growing regions include Mexico, Sicily, Algeria, Chile, Brazil, and northern Africa (Barbera et al., 1992
; Inglese et al., 2002
). In addition, the young cladodes (stem segments) of O. ficus-indica are harvested as a vegetable crop (often called nopalitos). Although this crop is less valuable worldwide than the fruit crop, vegetable products of O. ficus-indica are available in many local and commercial markets (Sáenz-Hernandez et al., 2002
). Various other uses have been reported for O. ficus-indica, including as a binding and waterproofing agent in adobe (Cárdenas et al., 1998
). Medicinal properties of O. ficus-indica have been documented as early as 1552 (Emmart, 1940
). Opuntia ficus-indica (along with other Opuntia and Nopalea species) has been grown from pre-Columbian times as a host plant for cochineal insects (Dactylopius coccus) for the production of valuable, vivid red and purple dyes (Donkin, 1977
; Nobel, 1994
). See Anderson (2001)
for a near-exhaustive review of the various other uses of O. ficus-indica.
Early European botanists (often referring to Pliny or Theophrastus) called this cactus Ficus indica (Donkin, 1977
), although some found this to be an unsuitable name, as the plant did not resemble the Indian fig (possibly Ficus benghalensis L.) already known (Anderson, 2001
). Linnaeus published Cactus opuntia and C. ficus-indica in Species Plantarum. Miller combined these into Opuntia ficus-indica in 1768. In the recorded history of the Old World, O. ficus-indica was certainly known at the beginning of the 16th century (Donkin, 1977
; Casas and Barbera, 2002
), and it is believed that this species accompanied Columbus in his first return to Lisbon in 1493 (Russell and Felker, 1987
; Anderson, 2001
), placing O. ficus-indica in the Caribbean by at least the late 1400s, although whether it is native there is unknown. The plants are also recorded in cultivation in Tlaxcala, Mexico, in 1519 (Diaz del Castillo, 1632 in Idell, 1957
). Opuntia ficus-indica fruits and shoots were also reportedly consumed by the Maya of southeastern Mexico (Coe, 1994
). There is also some evidence for the use of O. ficus-indica by the Nazca of Peru, placing these plants in South America at a very early date (Sejuro, 1990
). Other workers maintain that this taxon was unknown in pre-Columbian South America (Towle, 1961
; Baker, 2002
). The succulent, ever-fresh cladodes were certainly a novelty to late 15th century and later Europeans (Donkin, 1977
) and were widely included in ships' stores as insurance against scurvy (Kiesling, 1998
). This practice is thought to have contributed greatly to the present naturalized range of Opuntia ficus-indica throughout arid and semiarid habitats of the world (Anderson, 2001
; Casas and Barbera, 2002
; Sáenz-Hernandez et al., 2002
). This widespread propagation (intended and unintended) throughout the Mediterranean obscured the geographic origins of this species; many early European botanists regarded this cactus to be native (Donkin, 1977
; Barbera et al., 1992
), as reflected in Cactus opuntia L. (i.e., spiny plant from near Opus, Greece; Anderson, 2001
). This Mediterranean naturalization may now be conceived as complete, as the Israelis of the mid-20th century often adopted the (believed-indigenous) sabras as a symbol of their struggle (and humanity) in adverse desert conditions (Uris, 1959
).
Although most recent authors concede that this species is not native to the Old World, the geographic and evolutionary origins of Opuntia ficus-indica remain clouded in obscurity (Britton and Rose, 1919
; Bravo-Hollis, 1978
; Benson, 1982
; Anderson, 2001
). This mystery arises partly from the widespread cultivated distribution of the plants, both within and away from the New World (Anderson, 2001
), but also from the phenotypic variability and artificial selection of the plants (Benson, 1982
). The specific epithet (from P. Miller, 1768) may reflect the 16th-century European opinion that the plants are native to the West Indies (Barbera et al., 1992
; Casas and Barbera, 2002
). The name "tuna" is Caribbean in origin (Bravo-Hollis, 1978
; Kiesling, 1998
). Other early work proposed that O. ficus-indica was a spineless cultivar derived from O. megacantha, a species of central Mexico (Griffiths, 1914
). A recent, important paper explored this relationship with amplified fragment length polymorphism (AFLP) data and reported that O. ficus-indica had the closest affinity with O. megacantha (Labra et al., 2003
), corroborating the Griffiths (1914)
hypothesis. Other authors, however, consider O. megacantha also to be a cultivated taxon (Benson, 1982
) or a name applied to multiple ruderal reversions to spininess from escaped, cultivated O. ficus-indica (Kiesling, 1998
) and treat O. megacantha as a later synonym (Benson, 1982
; Kiesling, 1998
). Uphof (1968)
and Zeven and Zhukovsky (1975
, p. 164) place the origin of this cactus within "Mexico" or the "Central American and Mexican centre" of domestication, but without reference to a specific region. Some recent cytological work proposes that octoploid, cultivated O. ficus-indica is derived from a diploid Mexican (but unnamed) progenitor (Kiesling, 1998
). Benson (1982)
states that O. ficus-indica is native to mild tropical upland habitat (not deserts), but does not state where. Given the conflicting, sometimes confusing, and often unclear hypotheses as to the origins of this cactus crop, a wide molecular phylogenetic analysis has potential to elucidate the biogeography of this species. The current study addresses the biogeographic and evolutionary origins of O. ficus-indica through modern molecular means. To this end, I have gathered and analyzed DNA sequence data from a number of accessions of O. ficus-indica representing plantings throughout the world.
|
METHODS AND MATERIALS |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODS AND MATERIALSRESULTS AND DISCUSSIONLITERATURE CITED |
|---|
) and include a broad sample of O. ficus-indica accessions. A list of specimens used in this study is found in Appendix 1 (see Supplemental Data accompanying the online version of this article). Total DNA was extracted from fresh tissue using a protocol for mucilaginous tissues (Griffith and Porter, 2003
). Amplification of the internal transcribed spacer (nrITS) region of the nuclear ribosomal DNA follows Columbus et al. (1998)
. Florescent sequencing used Big Dye (Applied Biosystems, Foster City, California, USA) chemistry, according to the manufacturer's specifications. All DNA sequence data was gathered using an Applied Biosystems 3100 Genetic Analyzer. Chromatograms derived from sequencing were edited and consensus sequences obtained using Sequencher version 4.1 (Gene Codes, Ann Arbor, Michigan, USA). Consensus sequences were aligned manually via Se-Al version 2.0a7.2 (Rambaut, 1996
); sequence alignment was unambiguous. A Bayesian analysis of the data was performed with MrBayes version 2.01 (Huelsenbeck and Ronquist, 2001
). For each analysis, a site-specific gamma model was employed. A random starting tree was used, and four Markov chain Monte Carlo (MCMC; Metropolis et al., 1953
) replicates were run for 250 000 generations, sampling every 50. Metropolis-coupled MCMC analyses were performed using the Metropolis-Hastings-Green algorithm (Huelsenbeck and Ronquist, 2001
), as implemented by Mr. Bayes. The log likelihood (lnL) for all sampled trees was viewed and graphed in Microsoft Excel (Microsoft, Seattle, Washington, USA). Trees from the burn-in period (Huelsenbeck and Ronquist, 2001
) were discarded, and a majority rule consensus tree was obtained with PAUP* version 4.10ß (Swofford, 1998
) for the remaining trees sampled. This Bayesian analysis was performed 10 times, and the results from each run compared for consistency. Estimations of confidence in the clades obtained by the Bayesian analysis are the posterior probabilities of those clades occurring given the data (Miller et al., 2002
), which are indicated by the percentage consensus values obtained by PAUP. These values are interpreted similarly to bootstrap percentage values on a maximum likelihood tree (Huelsenbeck and Ronquist, 2001
). |
RESULTS AND DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODS AND MATERIALSRESULTS AND DISCUSSIONLITERATURE CITED |
|---|
; Bravo-Hollis, 1978
; Anderson, 2001
). This clade excludes arborescent plants from the Caribbean (Consolea spp. and O. boldinghii) and from South America and the Galapagos (O. eichios, O. galapageia, O. megasperma, and O. sulfurea) included in this study. Also notably excluded from the O. ficus-indica clade are O. durangensis and O. robusta, two large, polyploid, fleshy-fruited taxa from central and northern Mexico. Opuntia durangensis can often be very large and treelike (to 5 m; personal observation) and is found in the central and southern Chihuahuan Desert region (Anderson, 2001
; personal observation); Opuntia robusta (nopal tapon) is cultivated throughout Mexico for its large edible fruits (Anderson, 2001
) or for ornamental purposes (personal observation).
|
|
). This codex includes a representation of Opuntia cladodes amongst other items such as ocelot and jaguar skins (Fig. 4). This is the only early colonial period representation of Opuntia as a possible trade item, although the plant is often depicted in such codices outside of this context (Emmart, 1940
; Robertson, 1959
). This depiction may also represent a location (Xoconochco) as in the Codex Mendocino (Penafiel, 1885
). Cochineal dye, for which Opuntia cultivation is required, is also depicted here as paid tribute to the Aztecs (Berdan and Anwalt, 1992
; Fig. 5).
|
|
; Russell and Felker, 1987
). It seems conceivable that these plants were also brought to South America in pre-Columbian times, although their early presence in Peru is disputed (Towle, 1961
; Sejuro, 1990
); there is evidence that the pre-Columbian Incas certainly cultivated cochineal, however (Donkin, 1977
). A summary of the biogeographic conclusions supported by the present study is presented in Fig. 6.
|
Natural hybridization
Polyploidy and hybridization are well documented in the opuntioid cacti (Benson and Walkington, 1965
; Grant and Grant, 1971b
, 1979
; Baker and Pinkava, 1987
, 1999
; Griffith, 2001a
, b
, 2003
; Pinkava, 2002
). Opuntia ficus-indica is octaploid (Pinkava, 2002
), possibly through ancient allopolyploidy. Natural biological events may have led to the pattern of relationships in O. ficus-indica recovered for the ITS data set.
Human manipulation
If O. ficus-indica is of hybrid origin, it is conceivable that the hybridization was human facilitated. This may have occurred indirectly, by bringing allopatric ancestors into cultivated sympatry. One intriguing possibility is that hybridization of ancestral O. ficus-indica stock was instead performed directly by Mesoamerican agriculturalists. There is evidence for the intensive selective breeding of fruit crops by pre-Columbian peoples (Bergh, 1995
); it is possible that Mesoamerican knowledge of plant reproduction included pollination technology. Descriptions and depictions of Mesopotamian date palm (Phoenix spp.) cultivation dating to 1750 BC or earlier are interpreted as the earliest documentation of human use of artificial pollination in fruit crop selection (Paley, 1976
; Roth, 2000
; Janick, 2005
). Although there is no direct evidence of pollination for crop manipulation of O. ficus-indica in contemporary Mesoamerica, the early knowledge of its biological function is suggested by the depiction of hummingbird pollination in the Primeros Memoriales of Sahagún (ca. 1558; Fig. 7).
|
, who states that most fruit cultivation was likely achieved through maintenance of unique clones, in contrast to cereal cultivation. Therefore, it is possible that the taxonomic concept of O. ficus-indica may circumscribe a nonmonophyletic group of convergent cultivars derived from different parental species.
Lineage sorting
Another possible explanation for this pattern of genetic relationships is lineage sorting (Pamilo and Nei, 1988
) of multiple ITS copies in a widespread ancestral population of Opuntia that gave rise to O. ficus-indica and its close relatives.
These four hypotheses should be tested through other independent molecular investigations. Other DNA sequence-based phylogenetic estimations may be of use, but the low level of variation in the ITS region for the genus Opuntia may indicate that a genome-wide approach may yield more useful variation. Reticulate evolution in Opuntia has been investigated via random amplified polymorphic DNA (RAPD) data (Mayer et al., 2000
; Griffith, 2003
), and some modern clones of O. ficus-indica have been characterized via this method (Wang et al., 1998
) as being either for fruit or vegetable production. Other data that may elucidate these relationships might include AFLP (as in Labra et al., 2003
) and microsatellite data. This population genetic approach may elucidate potential differences in heterozygosity between O. ficus-indica populations from different localities within central Mexico and abroad, which could further pinpoint the location of the wild progenitors of this species. Ongoing investigations will involve these data types interpreted in a historical and archaeological context and may illuminate the ancient selection of these plants by the oldest inhabitants of Mexico.
|
FOOTNOTES |
|---|
2 E-mail: michael.patrick.griffith{at}cgu.edu
|
LITERATURE CITED |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODS AND MATERIALSRESULTS AND DISCUSSIONLITERATURE CITED |
|---|
Baker M. A. 2002 Chromosome numbers and their significance in some Opuntioideae and Cactoideae (Cactaceae) of mainland Ecuador and Peru. Haseltonia 9: 69-77
Baker M. A. D. J. Pinkava 1987 A cytological and morphometric analysis of a triploid apomict, Opuntia x kelvinensis (subgenus Cylindropuntia, Cactaceae). Brittonia 39: 387-401[CrossRef][ISI]
Baker M. A. D. J. Pinkava 1999 A new Arizona hybrid cholla, Opuntia x campii (Cactaceae). Cactus and Succulent Journal (U.S.) 71: 320-322
Barbera G. F. Carimi P. Inglese 1992 Past and present role of the Indian-fig prickly-pear (Opuntia ficus-indica (L.) Miller, Cactaceae) in the agriculture of Sicily. Economic Botany 46: 10-20[ISI]
Barrientos P. F. 1966 El nopal y su utilización en Mexico. La Sociedad Mexicana de Historia Natural, Mexico City, Mexico
Basile F. 2001 Economic aspects of cactus pear production and market. Journal of the Professional Association for Cactus Development 5: 31-46
Benson L. H. 1982 The cacti of the United States and Canada. Stanford University Press, Stanford, California, USA
Benson L. H. D. L. Walkington 1965 The southern California prickly pears—invasion, adulteration, and trial-by-fire. Annals of the Missouri Botanical Garden 52: 262-273[CrossRef]
Berdan F. R. P. R. Anwalt 1992 The codex Mendoza, vol. III, Facsimile. University of California Press, Berkeley, California, USA
Bergh B. O. 1995 Avocado: Persea americana (Lauraceae). In J. Smartt and N. W. Simmonds [eds.], Evolution of crop plants, 2nd ed., 240–245. Longman Scientific & Technical, Essex, UK
Bravo-Hollis H. 1978 Las Cactáceas de México, 2nd ed. Universidad Nacional Autonóma de México, Mexico City, Mexico
Britton N. L. J. N. Rose 1919 The Cactaceae, vol. 1. Carnegie Institution, New York, New York, USA
Callen E. O. 1967 Analysis of the Tehuacan coprolites. In D. S. Byers [ed.], Prehistory of the Tehuacan valley, vol. 1, Environment and subsistence, 261–289. University of Texas Press, Austin, Texas, USA
Cárdenas A. W. M. Arguelles F. M. Goycoolea 1998 On the possible role of Opuntia ficus-indica mucilage in lime mortar performance in the protection of historical buildings. Journal of the Professional Association for Cactus Development 3. Online at http:// www.jpacd.org/contents1998.htm
Casas A. G. Barbera 2002 Mesoamerican domestication and diffusion. In P. S. Nobel [ed.], Cacti: biology and uses, 143–162. University of California, Berkeley, California, USA
Casas A. J. Caballero C. Mapes S. Zárate 1997 Manejo de la vegetación, domesticación de plantas y origin de la agricultura en Mesoamérica. Boletín de la Sociedad Botánica de México 61: 31-47
Coe S. D. 1994 America's first cuisines. University of Texas Press, Austin, Texas, USA
Columbus J. T. M. S. Kinney R. Pant M. E. Siqueiros Delgado 1998 Cladistic parsimony analysis of internal transcribed spacer region (nrDNA) sequences of Bouteloua and relatives (Gramineae: Chloridoideae). Aliso 17: 99-130
Dodd A. P. 1936 The control and eradication of prickly pear in Australia. Bulletin of Entomological Research 27: 503-517
Donkin R. 1977 Spanish red: an ethnogeographical study of cochineal and the Opuntia cactus. Transactions of the American Philosophical Society 67: 1-77
Emmart E. W. 1940 The Badianus manuscript. The John Hopkins Press, Baltimore, Maryland, USA
Felger R. S. 1979 Ancient crops for the twenty-first century. In G. A. Ritchie [ed.], New agricultural crops. American Association for the Advancement of Science Symposium, vol. 38, 5–20. Westview Press, Boulder, Colorado, USA
Grant V. K. A. Grant 1971a Dynamics of clonal microspecies in cholla cactus. Evolution 25: 144-155[CrossRef][ISI]
Grant V. K. A. Grant 1971b Natural hybridization between the cholla cactus species Opuntia spinosior and Opuntia versicolor. Proceedings of the National Academy of Sciences, USA 68: 1993-1995
Grant V. K. A. Grant 1979 Hybridization and variation in the Opuntia phaeacantha group in central Texas. Botanical Gazette 140: 208-215
Griffith M. P. 2001a A new Chihuahuan Desert prickly pear, Opuntia x rooneyi. Cactus and Succulent Journal (U.S.) 73: 307-310
Griffith M. P. 2001b Experimental hybridization in northern Chihuahuan desert region Opuntia. Aliso 20: 37-42
Griffith M. P. 2003 Using molecular data to elucidate reticulate evolution in Opuntia. Madroño 50: 162-169
Griffith M. P. J. M. Porter 2003 Back to the basics: a simple method of DNA extraction for mucilaginous cacti. Bradleya 21: 126-128
Griffiths D. 1914 Reversion in prickly pears. Journal of Heredity 5: 222-225
Huelsenbeck J. P. F. Ronquist 2001 Mr. Bayes version 2.01. Department of Biology, University of Rochester, Rochester, New York, USA
Idell A. 1957 The Bernal Diaz chronicles: the true story of the conquest of Mexico. Doubleday, Garden City, New York, USA
Inglese P. F. Basile M. Schirra 2002 Cactus pear fruit production. In P. S. Nobel [ed.], Cacti: biology and uses, 163–183. University of California, Berkeley, California, USA
Janick J. 2005 Origins of fruits, fruit growing, and fruit breeding. Plant Breeding Reviews 25
Kiesling R. 1998 Origen, domesticación y distribución de Opuntia ficus-indica. Journal of the Professional Association for Cactus Development 3. Online at http://www.jpacd.org/contents1998.htm
Kluge M. I. P. Ting 1978 Crassulacean acid metabolism: an ecological analysis. Ecological studies series, vol. 30. Springer-Verlag, Berlin, Germany
Labra M. F. Grassi M. Bardini S. Imazio A. Guiggi S. Citterio E. Banfi S. Sgorbati 2003 Relationships in Opuntia Mill. genus (Cactaceae) detected by molecular marker. International Journal of Plant Science 165: 1129-1136
Mandujano M. C. C. Montaña I. Mendez L. Eeguiarte 1996 Reproductive ecology and inbreeding in Opuntia rastera (Cactaceae) in the Chihuahuan Desert: why are sexually derived recruitments so rare?. American Journal of Botany 83: 63-70[CrossRef][ISI]
Mayer M. S. L. M. Williams J. P. Rebman 2000 Molecular evidence for the hybrid origin of Opuntia prolifera (Cactaceae). Madroño 47: 109-115
Metropolis N. A. Rosenbluth M. Rosenbluth A. Teller E. Teller 1953 Equation of state calculations by fast computing machines. Journal of Chemistry and Physics 21: 1087-1092[CrossRef]
Miller R. E. T. R. Buckley P. S. Manos 2002 An examination of the monophyly of morning glory taxa using Bayesian phylogenetic inference. Systematic Biology 51: 740-753[CrossRef][ISI][Medline]
Nobel P. S. 1994 Remarkable agaves and cacti. Oxford University Press, New York, New York, USA
Nobel P. S. [ed.] 2002 Cacti: biology and uses. University of California, Berkeley, California, USA
Nobel P. S. E. De la Barrera D. W. Beilman J. H. Doherty B. R. Zutta 2002 Temperature limitations for cultivation of edible cacti in California. Madroño 49: 228-236
Ostolaza C. 1994 Cactus y etnobotánica. Quepo 8: 79-86
Paley S. M. 1976 King of the world: Ashur-nasir-pal II of Assyria 883– 859 B.C. Brooklyn Museum, New York, New York, USA
Pamilo P. M. Nei 1988 Relationships between gene trees and species trees. Molecular Biology and Evolution 5: 568-583[Abstract]
Penafiel A. 1885 Nombres geográficos de México. Lord Kingsborough, Mexico
Pinkava D. J. 2002 On the evolution of continental North American Opuntioideae. Succulent Plant Research 6: 59-98
Rambaut A. 1996 Se-Al. Sequence alignment editor, version 2.0a7.2. Department of Zoology, University of Oxford, Oxford, UK
Robertson D. 1959 Mexican manuscript painting of the early colonial period. Yale University Press, New Haven, Connecticut, USA
Roth M. 2000 The laws of Hammurabi. In W. W. Hallo [ed.], The context of scripture, vol. 2, 335–353. Brill, Boston, Massachusetts, USA
Russell C. E. P. Felker 1987 The prickly pears (Opuntia spp., Cactaceae): a source of human and animal food in semiarid regions. Economic Botany 41: 433-445
Sáenz-Hernandez C. J. Corrales-Garcia G. Aquino-Pérez 2002 Nopalitos, mucilage, fiber, and cochineal. In P. S. Nobel [ed.], Cacti: biology and uses, 211–234. University of California, Berkeley, California, USA
Sejuro N. O. 1990 Plantas Medicinals Utilizadas por los Curanderos de Nasca, 2nd ed. Boletín de Investigación en Tecnologías Nativas 5
Swofford D. L. 1998 PAUP*: phylogenetic analysis using parsimony (* and other methods), version 4. Sinauer, Sunderland, Massachusetts, USA
Towle M. A. 1961 The ethnobotany of pre-Columbian Peru. Aldine, Chicago, Illinois, USA
Uphof J. C. T. 1968 Dictionary of economic plants. Richard Mayr, Würzburg, Germany
Uris L. 1959 Exodus revisted. Doubleday, Garden City, New York, USA
Wang X. P. Felker M. D. Burrow A. H. Paterson 1998 Comparison of RAPD marker patterns to morphological and physiological data in the classification of Opuntia accessions. Journal of the Professional Association for Cactus Development 3: 3-14
Zeven A. C. P. M. Zhukovsky 1975 Dictionary of cultivated plants and their centres of diversity: excluding ornamentals, forest trees and lower plants. Centre for Agricultural Publishing and Documentation, Wageningen, Netherlands
This article has been cited by other articles:
|
|
 |
|
  S. Bory, P. Lubinsky, A.-M. Risterucci, J.-L. Noyer, M. Grisoni, M.-F. Duval, and P. Besse Patterns of introduction and diversification of Vanilla planifolia (Orchidaceae) in Reunion Island (Indian Ocean) Am. J. Botany, July 1, 2008; 95(7): 805 - 815. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. E. Hughes, R. Govindarajulu, A. Robertson, D. L. Filer, S. A. Harris, and C. D. Bailey Serendipitous backyard hybridization and the origin of crops PNAS, September 4, 2007; 104(36): 14389 - 14394. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
