Download Fecha/hora: 20/02/2017 09:54:56 Biblioteca(s): INIA Tacuarembó

Fecha/hora: 08/06/2017 19:58:29
Biblioteca(s): INIA Tacuarembó.
Fecha corriente: 21/02/2014
Fecha de la última actualización: 23/03/2017
Autoria: REYNO, R.
Afiliación: RAFAEL ALEJANDRO REYNO PODESTA, INIA (Instituto Nacional de Investigación
Agropecuaria), Uruguay.
Título: Improving acid and aluminum tolerance in alfalfa using breeding and genomics : tesis
Ph.D.
Año de publicación: 2012
Fuente/Imprenta: Athens (USA): University of Georgia, 2012.
Páginas: 116 p.
Idioma: Inglés
Contenido: Alfalfa, Medicago sativa L., is an important forage crop in the U.S. and worldwide.
However, in acid soil, its productivity and persistence dramatically decrease. Acid-soil
syndrome causes a severe toxicity that inhibits root growth and development exacerbated
by Al+3. Breeding and genomic approaches to improve acid/Al tolerance provide new
opportunities to grow alfalfa in lands considered marginal for alfalfa growth. In this
study, three different approaches were used to identify and to evaluate acid/Al tolerance
in alfalfa: (1) identification and mapping of quantitative trait loci (QTL) associated with
acid/Al tolerance, (2) evaluation of transgenic plants over-expressing Pseudomonas
aeruginosa citrate synthase (CS) and/or a gene coding for a plasma membrane
H+-ATPase from Daucus carota (DcPA1), and (3) comparison of genetic gain for acid/Al
tolerance as assessed by seedling biomass production in acidic soil under greenhouse
conditions. Single-factor analysis and interval mapping identified QTL for Al tolerance
on Altet-4 and on NECS-141 linkage groups. The phenotypic variation explained by
individual QTL ranged from 9.5 to 35.3%. Some of these QTL were detected in multiple
environments and for multiple traits while others were environment-specific. Four
isogenic T2 populations, containing neither, one, or both transgenes (CS+DcPA1) were
evaluated for acid/Al tolerance. The transgenic populations containing either CS or
DcPA1 or both genes showed higher acid/Al tolerance than the non-transgenic
population. No advantage of combining both transgenes in the same genetic background
was observed. Lower levels of Al in shoot tissue were observed for the transgenic
populations over the non-transgenic population. The comparison of selection methods
showed that the phenotypic recurrent selection with gridding in unlimed soil was most
effective at improving the Bulldog 805 population for shoot dry weight. This method of
selection was the most effective in terms of the resources used and the responses
achieved. Direct selection in unlimed soil resulted in increased alfalfa growth in acid and
Al-rich soils compared to selection in limed soil. The information generated in these three
experiments can be useful in improving our understanding of acid/Al tolerance in alfalfa
and in developing cost-effective and efficient methods to obtain enhanced alfalfa
germplasm in the future.
Palabras-Clave: AMONG-WITHIN FAMILY SELECTION; CITRATE SYNTHASE; GREENHOUSE
SOIL-BASED ASSAY; GRID SELECTION; PLASMA MEMBRANE H+-ATPASE;
QUANTITATIVE TRAIT LOCI; RECURRENT SELECTION; TRANSGENIC;
UNLIMED AND LIMED SOILS.
Thesagro: ALFALFA; MEDICAGO SATIVA.
Categoría del tema: -URL: http://www.ainfo.inia.uy/digital/bitstream/item/3710/1/Reyno-Rafael-TESISphd.pdf
Registro original: INIA Tacuarembó (TBO)
Ejemplares: TBO - (19178-1) - PXI - TS - PP - T 633.31 REYi - - EN 6369 - DIS