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14 resultados encontrados para: AUTOR: Brush, Stephen B
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1.
Artículo
Assessing maize genetic erosion
Brush, Stephen B. ; Bellon Corrales, Mauricio Rafael (coaut.) ; Hijmans, Robert J. (coaut.) ; Orozco Ramírez, Quetzalcóatl (coaut.) ; Perales Rivera, Hugo Rafael (coaut.) ; Van Etten, Jacob (coaut.) ;
Contenido en: PNAS. Proceedings of the National Academy of Sciences of the United States of America Vol. 112, no. 1, E1 (January 2015), p. E1-E1 ISBN:1091-6490
PDF PDF

2.
- Artículo con arbitraje
A minor role for environmental adaptation in local–scale maize landrace distribution: results from a common garden experiment in Oaxaca, Mexico
Orozco Ramírez, Quetzalcóatl ; Brush, Stephen B. (coaut.) ; Grote, Mark N. (coaut.) ; Perales Rivera, Hugo Rafael (coaut.) ;
Contenido en: Economic Botany Vol. 68, no. 4 (December 2014), p. 383–396 ISSN: 0013-0001
Resumen en español

En la práctica agrícola generalmente se asume que el rendimiento es una de las razones por las cuales los agricultores tradicionales seleccionan una variedad local. Esto conlleva a la hipótesis de que los cultivares que utilizan los agricultores son los que tienen los rendimientos más altos en comparación con otros cultivares de la región. Nosotros probamos esta hipótesis estudiando las variedades utilizadas por agricultores indígenas en una región con un rango altitudinal de 400 a 1300 msnm en Oaxaca, México. Seleccionamos cuatro localidades, dos chatinas y dos mixtecas, dos a baja altitud y dos a altitud media. Establecimos jardines recíprocos en cada una para probar si los maíces de cada localidad producían más que los de otras localidades. Esto podría sugerir que esos cultivares fueron seleccionados porque están mejor adaptados a las condiciones locales. También probamos resistencia a enfermedades por hongos (pudrición causada por Fusariumspp) porque esta enfermedad fue mencionada por los agricultores como una de las principales en el cultivo de maíz. Los resultados mostraron que las muestras plantadas en la localidad donde fueron colectadas no siempre tienen los mayores rendimientos en comparación con muestras de otras localidades. Encontramos interacciones significativas entre el sitio de la parcela, fertilización y la localidad de origen de la muestra. Las muestras de la localidad chatina localizada a baja elevación tuvieron mejor rendimiento en la mayoría de los sitios, con y sin fertilizante.

En relación a pudrición de la mazorca, hay un poco de evidencia de que los cultivares son menos susceptibles cuando se siembran lejos de su localidad de origen. Estos resultados sugieren que factores sociales, tales como redes de semillas y pertenencia a un grupo étnico, podrían ser más importantes que la adaptación local en la determinación de la distribución de variedades locales en esta región.

Resumen en inglés

Agronomists usually assume that yield is a primary selection trait for farmers practicing traditional agriculture. They hypothesize that the landraces grown in farmers’ fields produce higher yields than other local landraces would, if grown in the same fields.We test this hypothesis in experimental gardens using maize landraces grown by indigenous farmers in a low– to mid–elevation region in Oaxaca, Mexico.We selected four villages, two Chatino and twoMixtec, two in low and two in middle elevations.We planted reciprocal common gardens in each village, in order to test whether or not local maize landraces were higher yielding in their respective villages—a finding that would suggest they are selected because they are better adapted to local conditions than landraces from other villages. We also tested resistance to a fungal disease (ear rot caused by Fusarium) that is cited by farmers in the region as a major problem for maize production. We found that maize samples planted in their villages of origin did not in general have higher yields than samples from other villages. There are significant interactions among common garden site, fertilizer use, and seed source.We found that landraces fromthe Chatino lowlands village performwell in most sites, with andwithout fertilizer. Regarding ear rot, there is some evidence that landraces are less susceptible when grown away from their villages of origin. These results suggest that social factors, such as seed networks and ethno–linguistic membership, may be more important than local environmental adaptation in determining the distribution of landraces in this region.


3.
Artículo
*En hemeroteca, SIBE-Campeche
A maize landscape: ethnicity and agro-biodiversity in Chiapas Mexico
Brush, Stephen B. ; Perales Rivera, Hugo Rafael (coaut.) ;
Contenido en: Agriculture, Ecosystems and Environment Vol. 121, no. 3 (July 2007), p. 211–221 ISSN: 0167-8809
Bibliotecas: Campeche
Cerrar
SIBE Campeche
46111-10 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-Campeche
Resumen en: Inglés |
Resumen en inglés

The ecology of maize (Zea mays L.) in Mexico, its center of domestication and diversity, has been researched for several decades. While the broad outlines of diversity and dynamics of native maize populations are known at the farm and national levels, these topics are less well known at the landscape level. Although environmental factors are the principal forces behind the overall diversity of the species in Mexico, recent research suggests that social origin, for instance community of residence or ethno-linguistic group, influences maize population structure at more local levels. A landscape perspective can help to determine whether these social factors operate in a consistent fashion across different environments. Case study data from Chiapas are presented and used to illustrate the role of ethnicity in understanding the ecology of maize diversity in Mexico. The paper contrasts the maize populations and management practices of Spanish speaking mestizos and Mayan language speaking indigenous people across four altitude zones in Chiapas. Environmental differences are primary in determining the overall pattern of maize diversity across the Chiapan landscape, but social origin has a significant effect on maize populations in all environments.


4.
Artículo
Tzeltal and tzotzil farmer knowledge and maize diversity in Chiapas, Mexico
Benz, Bruce F. ; Perales Rivera, Hugo Rafael (coaut.) ; Brush, Stephen B. (coaut.) ;
Contenido en: Current Anthropology Vol. 48, no. 2 (2007), p. 289-300 ISSN: 0011-3204
Bibliotecas: San Cristóbal
Cerrar
SIBE San Cristóbal
23577-30 (Disponible)
Disponibles para prestamo: 1
Resumen en: Inglés |
Resumen en inglés

Different maize races dominate the highland communities of the Tzotzil and the Tzeltal of highland Chiapas, Mexico. When Tzeltal and Tzotzil informants from four communities were asked to sort photographs of maize varieties from the two municipalities according to ear similarity and the pictured variety's ability to produce on their communities' lands, their responses revealed that they have a common system of maize classification based on color and that unnamed but culturally specific categories discriminate maize types according to ethno-linguistic group. The significance of these findings is that while color, a perceptually distinct but nonadaptive trait, dominates maize classification by these farmers, intermediate but unlabeled categories help to explain the geographic distribution of maize in the regional environment. Thus, ethno-linguistic diversity contributes to maize diversity.


5.
- Artículo con arbitraje
Maize diversity and ethnolinguistic diversity in Chiapas, Mexico
Perales Rivera, Hugo Rafael ; Benz, Bruce F. (coaut.) ; Brush, Stephen B. (coaut.) ;
Contenido en: Proceedings of the National Academy of Sciences Vol. 102, no. 3 (January 2005), p. 949–954 ISSN: 0027-8424
PDF PDF
Resumen en: Inglés |
Resumen en inglés

The objective of this study is to investigate whether ethnolinguistic diversity influences crop diversity. Factors suggest a correlation between biological diversity of crops and cultural diversity. Although this correlation has been noted, little systematic research has focused on the role of culture in shaping crop diversity. This paper reports on research in the Maya highlands (altitude > 1,800 m) of central Chiapas in southern Mexico that examined the distribution of maize (Zea mays) types among communities of two groups, the Tzeltal and Tzotzil. The findings suggest that maize populations are distinct according to ethnolinguistic group. However, a study of isozymes indicates no clear separation of the region’s maize into two distinct populations based on ethnolinguistic origin. A reciprocal garden experiment shows that there is adaptation of maize to its environment but that Tzeltal maize sometimes out-yields Tzotzil maize in Tzotzil environments. Because of the proximity of the two groups and selection for yield, we would expect that the superior maize would dominate both groups’ maize populations, but we find that such domination is not the case. The role of ethnolinguistic identity in shaping social networks and information exchange is discussed in relation to landrace differentiation.


6.
- Artículo con arbitraje
*En hemeroteca, SIBE-San Cristóbal
Dynamic management of maize landraces in Central Mexico
Perales Rivera, Hugo Rafael ; Brush, Stephen B. (coaut.) ; Qualset, Calvin O. (coaut.) ;
Clasificación: AR/633.15 / P4
Contenido en: Economic Botany Vol. 57 , no. 1 (June 2003), p. 21-34 ISSN: 0013-0001
Cerrar
SIBE Campeche
ECO040001126 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE Chetumal
ECO030000204 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE San Cristóbal
B2067 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE Tapachula
ECO020002832 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE Villahermosa
ECO050000204 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-San Cristóbal
Resumen en: Inglés |
Resumen en inglés

Conservatiomsts of crop genetw resources have feared that m situ conservatton was not viable for agriculture prectsely because of changes resultmg from introduction of new varwtws of existing crops, new crops, and new farm practices In addmon, conservation within farming systems necessarily implies a constantly changmg crop populatton resulting from the processes of crop evolutton. Even though in situ conservatton of crop genetic resources ts now generally understood to be dynamw, there are few examples of how evolutton takes place m farmers fields. Thts study descrtbes several changes m maize landraces in four communmes along an altitude transect in Central Mexwo (1200 to 2400 masl) While true modern varieties have not been wtdely adopted in the study region, farmer management results m numerous changes in malze landrace populanons Fwe types of dynamtc management were observed" (1) purposeful hybrtdlzatton between tradmonal and modern maize types, (2) posstble creation of a new maize landrace by dtrectzonal selectton of the progeny of hybrtdlzatton between two tradttlonal landraces, (3) dtsplacement of a local landrace by the introductton of a modern varwty and a non-local landrace, (4) mamtenance of stable populattons of a locally dommant landrace, and (5) market-driven selectton for a minor variety We concur that m sttu conservation of crops must be conceived as an open process where the objecttve ts not to maintain historw varletws or stattc genetic condittons. Rather, m sttu conservation of crops ts totally in the hands of the farmer, although mterventions may be destgned to influence farmers' management of agrobtodtverstty.


7.
- Artículo con arbitraje
*En hemeroteca, SIBE-San Cristóbal
Landraces of maize in Central Mexico: an altitudinal transect
Perales Rivera, Hugo Rafael ; Brush, Stephen B. (coaut.) ; Qualset, Calvin O. (coaut.) ;
Clasificación: AR/633.157275 / P4
Contenido en: Economic Botany Vol. 57, no. 1 (June 2003), p. 7-20 ISSN: 0013-0001
Cerrar
SIBE Campeche
ECO040001128 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE Chetumal
ECO030000207 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE San Cristóbal
B5746 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE Tapachula
ECO020006202 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE Villahermosa
ECO050002673 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-San Cristóbal
Resumen en: Inglés |
Resumen en inglés

Conservatwn of crop genetw resources is now considered an important component of sustainable agricultural development. If conservation of genetic resources for agriculture is to be successful, a more complete understanding of the dynamws affecting tradmonal (landrace) crop populatwns ts needed. We conducted a study of maize-based agrwulture in the Central Highlands of Mexico in communities at 2400, 1700, 1400, and 1200 masl to assess the status of traditional varieties in an area characterized by thorough integration into the national economy Our research contradwts the view that modem varietws perstst because of marginal conditions, deficient infrastructure, weaker markets, or tradittonal attitudes. One or two landraces dominated htghland maize populations and farmers appeared to be more conservative in terms of their emphasis on traditional maize varieties than at lower elevations. The dominance of traditional varieties in the highlands is well known but poorly explained, and the coexistence of traditional and modem varieties in the mid-elevattons was unexpected. Our highland study area has good roads, is near Mexwo City, and Is less than 50 km away from four major crop research institutes that have done maize breeding since 1950"s. We suggest that in sita conservation of maize genetic resources in the htghlands ts sustained because the landraces there have good agronomw performance and are highly valued by farmers for their end-use qualities. At the mid-elevations, competition between local and modem maize was sharpest, and farmers have found that both landraces and tmproved varietws suit their needs, hence enhancing genetic diversity. Interventions and incenttves would approprtately be carrwd out here to assure m sltu conservation of locally adapted landraces of maize.


8.
Libro
*En proceso técnico. Solicítelo con el bibliotecario(a) de SIBE-San Cristóbal
Genes in the field: on-farm conservation fo crop diversity / Edited by Stephen B. Brush, Ph. D.
Brush, Stephen B. (autor) ;
Rome, Italy : International Plant Genetic Resources Institute :: International Development Research Centre :: Lewis Publishers , 2000
Bibliotecas: San Cristóbal
Cerrar
SIBE San Cristóbal
60100-10 (Disponible)
Disponibles para prestamo: 1
Nota: En proceso técnico. Solicítelo con el bibliotecario(a) de SIBE-San Cristóbal

9.
- Artículo de divulgación
*En hemeroteca, SIBE-San Cristóbal, SIBE-Tapachula
Transgenic crops: a cautionary tale
Nigh Nielsen, Ronald (autor) ; Benbrook, Charles (autor) ; Brush, Stephen B. (autor) ; García Barrios, Luis Enrique (autor) ; Ortega Paczka, Rafael (autor) ; Perales Rivera, Hugo Rafael (autor) ; Abbo, Shahal (coaut.) ; Rubin, Baruch (autor) ;
Disponible en línea
Contenido en: Science Vol. 287, no. 5457 (Feb. 2000), p. 1927-1927 ISSN: 0036-8075
Bibliotecas: San Cristóbal , Tapachula
Cerrar
SIBE San Cristóbal
7320-50 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE Tapachula
7320-30 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-San Cristóbal, SIBE-Tapachula

10.
- Capítulo de libro con arbitraje
Agronomic and economic competitiveness of maize landraces and in situ conservation in Mexico
Perales Rivera, Hugo Rafael ; Brush, Stephen B. (coaut.) ; Qualset, Calvin O. (coaut.) ;
Contenido en: Farmers gene banks and crop breeding: economic analyses of diversity in wheat maize and rice Norwell, Massachusetts : Kluwer Academic Publishers, 1998 p. 109-125 ISBN:978-0-7923-8370-3
Resumen en: Inglés |
Resumen en inglés

When public attention initially focused on the conservation of crop genetic resources in the late 1960s, scientists advocated ex situ conservation because of their belief that modern varieties would inevitably replace traditional varieties (Frankel, 1970a, 1970b). This belief was based on two key assumptions. The first, explicit assumption is that modern varieties are always superior to traditional varieties in yield and economic profitability. A second, implicit assumption is that all farmers share the objective of maximizing expected profits. Since superior modern varieties would sooner or later replace landraces, in situ conservation of crops was dismissed a priori as non-viable. Interventions such as subsidies would be required to maintain cultivation of traditional varieties in the face of the high opportunity costs of growing them (Ford-Lloyd and Jackson, 1986), especially as greater food production was needed to feed the ever- increasing world population.