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 - Comparative SNP and haplotype analysis reveals a higher genetic diversity and rapider LD decay in tropical than temperate germplasm in maize(Public Library of Science, 2011) Yanli Lu; Shah, T.; Zhuanfang Hao; Taba, S.; Shihuang Zhang; Shibin Gao; Jian Liu; Moju Cao; Jing Wang; A. Bhanu Prakash; Tingzhao Rong; Yunbi XuUnderstanding of genetic diversity and linkage disequilibrium (LD) decay in diverse maize germplasm is fundamentally important for maize improvement. A total of 287 tropical and 160 temperate inbred lines were genotyped with 1943 single nucleotide polymorphism (SNP) markers of high quality and compared for genetic diversity and LD decay using the SNPs and their haplotypes developed from genic and intergenic regions. Intronic SNPs revealed a substantial higher variation than exonic SNPs. The big window size haplotypes (3-SNP slide-window covering 2160 kb on average) revealed much higher genetic diversity than the 10 kb-window and gene-window haplotypes. The polymorphic information content values revealed by the haplotypes (0.436?0.566) were generally much higher than individual SNPs (0.247?0.259). Cluster analysis classified the 447 maize lines into two major groups, corresponding to temperate and tropical types. The level of genetic diversity and subpopulation structure were associated with the germplasm origin and post-domestication selection. Compared to temperate lines, the tropical lines had a much higher level of genetic diversity with no significant subpopulation structure identified. Significant variation in LD decay distance (2?100 kb) was found across the genome, chromosomal regions and germplasm groups. The average of LD decay distance (10?100 kb) in the temperate germplasm was two to ten times larger than that in the tropical germplasm (5?10 kb). In conclusion, tropical maize not only host high genetic diversity that can be exploited for future plant breeding, but also show rapid LD decay that provides more opportunity for selection.
Publication - Latin American maize germplasm regeneration and conservation(CIMMYT, 1997) Taba, S.During 1992-96, a collaborative project involving genebanks of 14 countries in Latin America, with economic and/or technical support from USDA under project Noah, the USDA-ARS National Seed Storage Laboratory (NSSL), and CIMMYT, rescued nearly 7,000 endangered collections of maize landraces and strengthened cooperation on maize genetic resource conservation and management in the Americas. This publication contains information from a wrap-up meeting of all participants, including detailed descriptions of activities, results, and plans for subsequent regeneration efforts.
Publication - Wellhausen-Anderson plan genetic resources center: operations manual 2004(CIMMYT, 2004) Taba, S.; Van Ginkel, M.; Hoisington, D.A.; Poland, D.In 2004, CIMMYT restructured its research programs into six new global and ecoregional programs. One of these, the Genetic Resources Program, is now home to the maize and wheat germplasm collections in CIMMYT’s gene bank. This new organizational structure indicates the high importance and visibility that CIMMYT places on our role as custodians of maize, wheat, and related species genetic resources. One of the first priorities of the program was to update the operations manual for the gene bank. The result of this effort is this publication, the Wellhausen-Anderson Genetic Resources Center Operations Manual. Many staff contributed to this version that was ultimately assembled and edited by Suketoshi Taba, maize germplasm collection manager, Maarten van Ginkel, wheat germplasm collection manager, David Poland, senior writer/ editor, and Dave Hoisington, Genetic Resources Program Director. The policies and procedures outlined in the manual represent those currently being used in the introduction, evaluation, mai tenance, regeneration, and distribution of genetic resources at CIMMYT. By following these procedures, CIMMYT ensures that the genetic resources entrusted to it in its germplasm collections are available to the world and that they maintain their genetic integrity while under CIMMYT’s custodianship. CIMMYT will continue to evaluate and update these policies and procedures. This is especially critical as new legal requirements come into force, such as the International Treaty of Plant Genetic Resources for Food and Agriculture, and other aspects of gene bank management come to the fore, such as requirements for monitoring the presence of transgenes.
Publication - Maize genetic resources(CIMMYT, 1997) Taba, S.This publication documents the origin and worldwide spread of maize from Mesoamerica, and describes the characterization, use, and conservation of maize genetic resources, including the crop's nearest wild relatives, teosinte and Tripsacum. Results of an international survey on the continued use of maize landraces in developing countries are reported, along with progress on the work of Latin American maize banks, in concert with CIMMYT, USAID, and USDA-NSSL, to regenerate their endangered holdings of maize landraces. An update is provided on collaborative research by CIMMYT and the French National Research Institute for Development Cooperation (ORSTOM) to transfer apomixis from Tripsacum to maize.
Publication - The CIMMYT Maize Germplasm Bank: genetic resource preservation, regeneration, maintenance, and use(CIMMYT, 1994) Taba, S.Originally developed as background information for participants in a 1992 external review of the CIMMYT Maize Germplasm Bank and related activities, this publication recounts CIMMYT's role in the early work of marshalling maize genetic resources, tells how the materials collected have been utilized, summarizes current activities of the Maize Germplasm Bank, and describes directions in which CIMMYT activities on maize genetic resources are evolving to encourage more effective and widespread use of bank accessions.
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