Person: Taba, S.
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- Genetic characterization of a core set of a tropical maize race Tuxpeño for further use in maize improvement(Public Library of Science, 2012) Weiwei Wen; Franco, J.; Chavez Tovar, V.H.; Jianbing Yan; Taba, S.The tropical maize race Tuxpeño is a well-known race of Mexican dent germplasm which has greatly contributed to the development of tropical and subtropical maize gene pools. In order to investigate how it could be exploited in future maize improvement, a panel of maize germplasm accessions was assembled and characterized using genome-wide Single Nucleotide Polymorphism (SNP) markers. This panel included 321 core accessions of Tuxpeño race from the International Maize and Wheat Improvement Center (CIMMYT) germplasm bank collection, 94 CIMMYT maize lines (CMLs) and 54 U.S. Germplasm Enhancement of Maize (GEM) lines. The panel also included other diverse sources of reference germplasm: 14 U.S. maize landrace accessions, 4 temperate inbred lines from the U.S. and China, and 11 CIMMYT populations (a total of 498 entries with 795 plants). Clustering analyses (CA) based on Modified Rogers Distance (MRD) clearly partitioned all 498 entries into their corresponding groups. No sub clusters were observed within the Tuxpeño core set. Various breeding strategies for using the Tuxpeño core set, based on grouping of the studied germplasm and genetic distance among them, were discussed. In order to facilitate sampling diversity within the Tuxpeño core, a minicore subset of 64 Tuxpeño accessions (20% of its usual size) representing the diversity of the core set was developed, using an approach combining phenotypic and molecular data. Untapped diversity represents further use of the Tuxpeño landrace for maize improvement through the core and/or minicore subset available to the maize community.
Publication - Identifying appropriate germplasm for participatory breeding: an example from the central Valleys of Oaxaca, Mexico(CIMMYT, 2000) Bellon, M.; Smale, M.; Aguirre Gomez, J.A.; Taba, S.; Aragon Cuevas, F.; Diaz, J.; Castro, H.Identifying the appropriate germplasm to be improved is a key component of any participatory breeding effort because of its implications for impacts on social welfare and genetic diversity. This paper describes a method developed to select a subset of 17 populations for a participatory breeding project from a set of 152 maize landraces. The larger set of landraces was collected in order to characterize, for conservation purposes, the maize diversity present in the Central Valleys of Oaxaca, Mexico. The method combines data representing the perspectives of both men and women members of farm households and those of genetic resources specialists, including professional plant breeders, gene bank managers, and social scientists. The different perspectives complement each other. The results show that when the choice of germplasm is based only on the perspective of genetic resources specialists, traits and materials that are important to farm households may be ignored. Such selections may be less valuable to farmers, limiting the impact of the participatory breeding effort on their livelihoods. However, the findings also indicate that relying solely on the perspectives of farm households may lead to lower diversity. Choosing populations based solely on either perspective involves a social cost-either in terms of diversity or in terms of farmer welfare. Although our approach has limitations, many of which are common to participatory research, it represents a systematic method for meeting one of the important challenges of participatory plant breeding.
Publication - Latin American maize germplasm conservation: regeneration, in situ conservation, core subsets, and prebreeding(CIMMYT, 2005) Taba, S.This publication describes progress in collaborative efforts to document, characterize, regenerate, and conserve (both in seed banks and on-farm in situ) maize seed collections from the Americas since 1998. Participants from North, Central, and South America took part in a workshop at the International Maize and Wheat Improvement Center (CIMMYT) from 7-10 April, 2003, to discuss these issues as well as those related to core subsets and prebreeding for maize. Topics covered included: the growth of CIMMYT’s maize collection through the Cooperative Regeneration Project; core subsets and prebreeding; conservation and use of local maize races in Oaxaca and Chihuahua; kernel characteristics and tortilla making quality of maize accessions from Mexico, the Caribbean, South and Central America; and enhancement of farmers’ varieties using an example from Coahuila, Mexico. Status reports on collections held in 12 countries in the region are provided.
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