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Accueil du site → Doctorat → Belgique → Amélioration variétale du sésame (Sesamum indicum L.) par mutation induite : effet de la mutagenèse sur la tolérance à la sécheresse et la productivité

Ghent University (2012)

Amélioration variétale du sésame (Sesamum indicum L.) par mutation induite : effet de la mutagenèse sur la tolérance à la sécheresse et la productivité

Seyni Boureima

Titre : Amélioration variétale du sésame (Sesamum indicum L.) par mutation induite : effet de la mutagenèse sur la tolérance à la sécheresse et la productivité

Veredeling van sesamvariëteiten (Sesamum indicum L.) via geïnduceerde mutatie : effect van mutagenese op droogtetolerantie en productiviteit

Auteur : Seyni Boureima

Université de soutenance : Ghent University

Grade : Dissertation 2012

Résumé
This study focused on the induction of genetic variability in sesame (Sesamum indicum L.) through radiation mutation with the purpose of contributing in broadening the genetic base of sesame and improving sesame yield in drought conditions in Senegal. Therefore, sesame seeds that originated from Senegal were exposed to gamma radiations of different levels to induce mutations. Germinating mutant seedlings were screened for drought resistance using Polyethylene glycol (PEG) 6000. Vegetative genotypes were subsequently on-grown in a glasshouse under limited irrigation to determine water deficit tolerance. Finally, genotypes were tested in the field for their yield potential with or without moisture stress. The key findings of this work were that radiations levels ranging from 300 to 400 Gy were efficient enough in generating a wide range of genetic variability with viable mutations in sesame. Moisture deficit corresponding to -1 MPa is the limit beyond which sesame seeds do not germinate. In the mild moisture stress treatment (-0.5 MPa), radicle elongation was promoted for the majority of the genotypes tested when compared to the control plants. During the drought tolerance screening at vegetative stage in glasshouse, the technique of chlorophyll fluorescence was used to evaluate the response to moisture stress of induced-genotypes of sesame by suspending the water supply to plants. Results showed that the maximum quantum yield of primary photochemistry (FV/FM) was less sensitive than performance index (PIABS) to moderate water stress. The drought factor index, calculated from PIABS, is proposed in this work to screen for improved drought tolerance in sesame. Genotypic variation for drought tolerance was evidenced in the mutated population at reproductive stage and several induced-mutants out-yielded the parental sources in drought conditions. In Conclusion, the use of induced mutation technique has allowed the induction of a great genetic variation in the sesame base collection of Senegalese Institute of Agricultural Research and obtaining mutants that out-yielded the parental sources in drought conditions.

Mots clés : Induced mutation, drought stress, genetic variation, yield.

Présentation

Page publiée le 2 décembre 2014, mise à jour le 18 septembre 2017