Evidence on the origin of cassava: Phylogeography of
            <i>Manihot esculenta</i>

Olsen, Kenneth M.; Schaal, Barbara A.

doi:10.1073/pnas.96.10.5586

Cited by 434 publications

(364 citation statements)

References 42 publications

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“…The contradiction between evidence supporting the earliest cultivation in the lowlands and the genetically ancestral position of Mexican Highland maize is therefore of particular interest. The disagreement is important, because the adaptive differences between highland and lowland maize are profound (14,29 the geography of crop origins has been resolved by locating the most likely wild ancestor (24,(30)(31)(32)(33). In the case of maize, however, the distribution of the wild ancestor does not coincide with the distribution of the cultivars most genetically similar to it.…”

Section: Discussionmentioning

confidence: 99%

Genetic signals of origin, spread, and introgression in a large sample of maize landraces

Heerwaarden

Doebley

Briggs

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

370

354

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The last two decades have seen important advances in our knowledge of maize domestication, thanks in part to the contributions of genetic data. Genetic studies have provided firm evidence that maize was domesticated from Balsas teosinte (Zea mays subspecies parviglumis), a wild relative that is endemic to the mid-to lowland regions of southwestern Mexico. An interesting paradox remains, however: Maize cultivars that are most closely related to Balsas teosinte are found mainly in the Mexican highlands where subspecies parviglumis does not grow. Genetic data thus point to primary diffusion of domesticated maize from the highlands rather than from the region of initial domestication. Recent archeological evidence for early lowland cultivation has been consistent with the genetics of domestication, leaving the issue of the ancestral position of highland maize unresolved. We used a new SNP dataset scored in a large number of accessions of both teosinte and maize to take a second look at the geography of the earliest cultivated maize. We found that gene flow between maize and its wild relatives meaningfully impacts our inference of geographic origins. By analyzing differentiation from inferred ancestral gene frequencies, we obtained results that are fully consistent with current ecological, archeological, and genetic data concerning the geography of early maize cultivation.T he geography of origins and diversification of agricultural species has important implications for unraveling the ecological context of Neolithic societies and for understanding current patterns of diversity in domesticated plants and animals. Traditionally the realm of archeology and botany (1, 2), the study of plant domestication has seen important contributions from genetics during the last two decades (3). Genetic data often provide evidence that is hard to obtain by other means, making it an invaluable complement to other lines of inquiry.As a case in point, molecular markers were instrumental in establishing the single domestication of maize (Zea mays subspecies mays) from an extant wild relative (4, 5). Maize was shown to originate from annual teosinte (Zea mays subspecies parviglumis, hereafter parviglumis) around 9,000 y B.P., placing domestication in the mid-to lowland regions of southwest Mexico where parviglumis grows endemically. As predicted by this result (6), excavations in the heart of parviglumis' distribution have produced the earliest (8,700 y B.P.) phytolith evidence for maize cultivation (7). Other finds from Tabasco (7,300 y B.P.) (8) and Panama (7,400 y B.P.) (9) also support an early presence of maize throughout the Meso-American lowlands.Although different types of evidence seemingly concur, questions nonetheless remain about the interpretation of the genetic data. While unequivocal with respect to maize's wild ancestor, marker evidence suggests that maize from the Mexican highlands, rather than from the lowlands, is most closely related to parviglumis and appears to have given rise to all cultivars currently grown throug...

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Section: Discussionmentioning

confidence: 99%

Genetic signals of origin, spread, and introgression in a large sample of maize landraces

Heerwaarden

Doebley

Briggs

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

370

354

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“…Sua domesticação ocorreu no continente sul americano, onde vem sendo cultivada há alguns milhares de anos (Olsen & Schaal, 1999;Allem, 1987). A partir da colonização européia, no século XVI, a cultura da mandioca se expandiu para a África e Ásia, onde se tornou a base da alimentação para milhões de pessoas.…”

Section: Introductionunclassified

Variabilidade genética de etnovariedades de mandioca, avaliada por marcadores de DNA

Mühlen¹,

Martins

Ando

2000

Sci. agric. (Piracicaba, Braz.)

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GENETIC DIVERSITY OF CASSAVA FOLK VARIETIES ASSESSED BY DNA MARKERSABSTRACT: The objective of this work was to quantify the genetic diversity among cassava folk varieties as well as to examine the distribution of the genetic diversity among varieties of different origin and type. Fifty-four cassava varieties were chosen from 4 Brasilian regions: 45 of the Amazon basin (23 from River Negro, 6 of the River Branco and 16 of the River Solimões) and 9 of the south coast of the São Paulo State, Brazil. The modern variety Mantiqueira was also included as a reference. Among these, 38 were bitter varieties and 17 sweet. Three different types of DNA markers were used: RAPD (randomly amplified polymorphic DNA), AFLP (amplified fragment length polymorphism) and microsatellites. Analysis of the results consisted of a description of band patterns, a calculation of similarity indexes (Nei & Li) and a principal coordinate analysis (PCoA) for each marker type. Heterozygosity, diversity indexes (DI, Weir) and genetic differentiation coefficients (G ST ) were calculated for the microsatellite loci.Genetic variability was more concentrated within regions, then among regions (G ST = 0.07). Mean heterozygosity was 56%. Mean similarity indexes were dependent on the marker used: S = 0.89 for RAPD, S = 0.85 for AFLP and S = 0.59 for microsatellites. PCoA analysis revealed groups, distinguishing bitter from sweet varieties.

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“…It is native from Brazil, according to philogeographic studies by Olsen and Schaal (1999), and it is exploited as one of the main foodstuffs of the populations in the tropical regions, because its storage roots are rich in starch. In the production systems where it is cultivated, cassava can be characterized as subsistence (Africa), economic (Thailand and China) or ethnic and cultural species (Brazil and other countries in South America) (Cereda, 2002).…”

Section: Introductionmentioning

confidence: 99%

Dry matter production and distribution in three cassava (Manihot esculenta Crantz) cultivars during the second vegetative plant cycle

Sagrilo

Filho

Pequeno

et al. 2008

Braz. arch. biol. technol.

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Evidence on the origin of cassava: Phylogeography of Manihot esculenta

Cited by 434 publications

References 42 publications

Genetic signals of origin, spread, and introgression in a large sample of maize landraces

Genetic signals of origin, spread, and introgression in a large sample of maize landraces

Variabilidade genética de etnovariedades de mandioca, avaliada por marcadores de DNA

Dry matter production and distribution in three cassava (Manihot esculenta Crantz) cultivars during the second vegetative plant cycle

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