Record keeping is not a static way to document history but rather a way for people in the present to engage with, and be affected by, the past. This is especially true in the case of online databases. Databases store information but their use also encourages the adoption of specific methodologies for apprehending reality because it is through those methodological agreements that the information in the database becomes relevant. In the summer of 2012 I spent four months observing and interviewing wheat researchers and database developers at a major agricultural research center in Mexico as part of my M.A. thesis project. This paper argues that people using the International Wheat Information System (IWIS) database at the International Maize and Wheat Improvement Center (CIMMYT) are involved in a process that documents wheat pedigree information while also enacting a reality based on assumptions about the value of certain types of human pedigree.

Doctor of Philosophy / Department of Agricultural Economics / Andrew P. Barkley / Previous studies show that there has been a deceleration in world wheat yield growth, specifically in irrigated areas, which has led some to believe that the potential for genetic gains is slowing. Some reports claim that the Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT) breeding program "reached a plateau" in the 1980s. Such a breeding plateau would have global ramifications, since it is often poor consumers who benefit the most from yield enhancement of staple crops including wheat. CIMMYT estimates that by 2020, the developing world will need 40% more wheat than it consumes today. Because of the lack of involvement by private breeders in most low-income countries, CIMMYT, whose germplasm is used extensively in the developing world, will need to ensure that modern varieties that they release are increasing in yield to meet the rising wheat demand in the developing world. CIMMYT, a non-profit organization, distributes improved germplasm to national agricultural research systems (NARS) for worldwide utilization. CIMMYT has consistently invested a large amount of public expenditures in wheat breeding research each year for several decades. Estimates of the impact of the wheat breeding program on increasing wheat yields provides information to scientists, administrators, and policy makers regarding the efficacy and return to these investments. Quantitative estimates of yield improvements due to the wheat breeding program provide important information for future funding decisions. Wheat lines released by CIMMYT during 1962-2002 were analyzed to estimate genetic yield increases associated with the CIMMYT breeding program using test plot data from the Yaqui Valley in Mexico from 1990-2002. Using several econometric techniques including a Just-Pope production function to account for multiplicative heteroscedasticity across the different varieties, results indicate that through the release of modern varieties CIMMYT has contributed 53.77 kg/ha to yield annually in Mexico’s Yaqui Valley during 1962-2002. Estimates of the gains attributed to CIMMYT’s breeding program on a global scale equal 481.47 million (2002) USD annually from 1990-2002. CIMMYT’s average total wheat breeding cost in from 1990-2002 was roughly 13.95 million USD making the average cost-benefit ratio approximately 1:34.

En este trabajo de Tesis se evalúo de manera extensiva la diversidad genética presente en los maíces nativos de Latinoamérica, combinando datos fenotípicos y genotípicos, con dos propósitos diferentes. El primero, un estudio donde la diversidad genética, las relaciones interpoblacionales y la estructura poblacional de los materiales nativos permitieron ligar aspectos históricos, antropológicos y arqueológicos del maíz para crear una historia consolidada de la migración del maíz desde su centro de origen en Mesoamérica hacia el Caribe y Sudamérica. El segundo, es explorado el potencial de las razas de maíz para proporcionar nuevos alelos favorables para mejoramiento. La evaluación fenotípica y genotípica conjunta de accesiones del Banco de Germoplasma con material mejorado por CIMMYT permitió identificar fuentes de variación alélica importante para algunos caracteres de interés como tolerancia a la sequía. La caracterización de la diversidad genética de los materiales nativos para la conservación y explotación con fines de mejoramiento es un enfoque muy prometedor en particular con el desarrollo constante de nuevas herramientas genéticas. / In this thesis work, the genetic diversity of Latin American maize landraces was evaluated extensively combining phenotypic and genotypic data, for two different purposes. First, to study the genetic diversity, relationships, and population structure of native materials allowing the linkage of historical, anthropological and archaeological data to create a consolidated history of maize migration from its origin center in Mesoamerica towards The Caribbean and South America. Second, to explore the potential of maize landraces to provide new elite alleles for breeding, the phenotypic and genotypic characterization of gene bank accessions compared to improved material from CIMMYT allowed the identification of important sources of allelic variation for traits of interest including drought tolerance. The characterization of native genetic diversity for conservation and exploitation towards breeding is a very promising approach, especially considering on going development of new genetic tools and methodologies

En este trabajo de Tesis se evalúo de manera extensiva la diversidad genética presente en los maíces nativos de Latinoamérica, combinando datos fenotípicos y genotípicos, con dos propósitos diferentes. El primero, un estudio donde la diversidad genética, las relaciones interpoblacionales y la estructura poblacional de los materiales nativos permitieron ligar aspectos históricos, antropológicos y arqueológicos del maíz para crear una historia consolidada de la migración del maíz desde su centro de origen en Mesoamérica hacia el Caribe y Sudamérica. El segundo, es explorado el potencial de las razas de maíz para proporcionar nuevos alelos favorables para mejoramiento. La evaluación fenotípica y genotípica conjunta de accesiones del Banco de Germoplasma con material mejorado por CIMMYT permitió identificar fuentes de variación alélica importante para algunos caracteres de interés como tolerancia a la sequía. La caracterización de la diversidad genética de los materiales nativos para la conservación y explotación con fines de mejoramiento es un enfoque muy prometedor en particular con el desarrollo constante de nuevas herramientas genéticas. / In this thesis work, the genetic diversity of Latin American maize landraces was evaluated extensively combining phenotypic and genotypic data, for two different purposes. First, to study the genetic diversity, relationships, and population structure of native materials allowing the linkage of historical, anthropological and archaeological data to create a consolidated history of maize migration from its origin center in Mesoamerica towards The Caribbean and South America. Second, to explore the potential of maize landraces to provide new elite alleles for breeding, the phenotypic and genotypic characterization of gene bank accessions compared to improved material from CIMMYT allowed the identification of important sources of allelic variation for traits of interest including drought tolerance. The characterization of native genetic diversity for conservation and exploitation towards breeding is a very promising approach, especially considering on going development of new genetic tools and methodologies