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sur le développement des zones arides et semi-arides

Titre : Recherche de nouvelles stratégies de multiplication du palmier dattier (Phoenix dactylifera L.)

Research of new strategies of date palm multiplication (Phoenix dactylifera L.)],

Auteur : Ben Abdallah, Abdallah

Grade : Doctorat 2000 Biotechnology, Agronomy, Society and Environment

Université de soutenance : Faculté universitaire des Sciences agronomiques de Gembloux

Résumé (UniCat)
The work analyzes differents strategies of propagation of four tunisien female cultivars of date palm (Allig, Deglet Nour, Kentichi and Menakher). Two tissue culture techniques (somatic embryogenesis and organogenesis) had been compared. Organogenesis proved to be little effective, while embryogenesis was applied with success. Periods of explants harvest favorable for obtaining embryogenic calluses have been specified in the conditions of Tozeur (south of Tunisia). The somatic embryogenesis protocol was improved during the phases of embryogenic callus induction, somatic embryos germination, and acclimatisation. In a second part, possibilities of apomixis induction were explored. Plants obtained by pollination with irradiated pollen were analyzed by flow cytometry and proved to be mainly diploïds. The genetic nature of these plants (doubled haploãds, or apomixis maternal origin or hybrids) is discussed. In a second approach for apoximis, gibberellic acid (AG3) induced date palm fructification when applied without pollination. Seeds, obtained through GA3 treatments, grew normally, contained a kernel and a viable embryo and exhibited 80 % germination. The germinated plantlets appeared diploãd. Histological studies showed, that self pollination was absent and these plants may have an apomictic origin. Exploratory results excluding true to type multiplication are discussed. Our work concludes to the best adequacy so far of somatic embryogenesis to meet the immediate imperatives for rapid multiplication of date palm. In the long run, production of seed without sexual hybridisation opens original perspectives, so much for the multiplication than for the genetic improvement of date palm.

Présentation (Agris FAO)