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Titre : Eficiencia de la selección y discriminación isotópica de carbono en trigo, bajo condiciones limitantes y no limitantes de humedad

Auteur : Martínez Rueda, Carlos Gustavo

Université de soutenance : Colegio de Postgraduados (COLPOS) Consejo Nacional de Ciencia y Tecnología (CONACYT)

Grade : Doctorado en Ciencias, especialidad en Genética 2008

Résumé
Drought is one of the main issues limiting the wheat production under rainfed conditions, but development of tolerant cultivars is hampered by low heritability of yield and a lack of effective selection strategies and more efficient selection traits. The objectives of this research work were : i) to identify optimum selection strategies and environments for wheat in rainfed conditions ; ii) to examine the variation in carbon isotopic discrimination and its efficiency as indirect selection criterion to increase grain yield of wheat. From an irradiated (60Co) composite of wheat variety Salamanca S-75 were derivate one group of 25 lines selected under continuous water limited conditions from M1 to M6 generation, and other group of 25 lines selected under non-water limited conditions from M4 to M6 generation. Both groups were evaluated through six contrasting environments, including rainfed, irrigation and drought conditions in Tecamac and Montecillo, Edo. De Mexico and Tlatizapan, Morelos. Results obtained confirm that early selection under water limited conditions and following under non- water limited conditions was the most efficient strategy to increase genetic gains to rainfed environments with or without water limitations. Higher genetic gains of yield could be obtained when selection and evaluation are performed in the same kind of environments. Broad variation was observed for carbon isotopic discrimination (Δ) between environments, and within groups of lines of each selection strategy. Δ shown high heritability and was positively correlated with grain and biological yield under most dry environment (Tecamac). Relative Selection efficiency for Δ was higher than efficiency of direct selection for grain yield biological yield and harvest index

Mots clés : Triticum aestivum L. ; Resistencia a sequía ; Ambiente de selección ; Selección indirecta ; Drought resistance ; Triticum aestivum L. ; Selection environment ; Indirect selection

Présentation

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