Embryogenèse somatique et variation somaclonale chez le blé dur et tendre (culture d'embryons matures et immatures)

Abstract

Six varieties of wheat resulting from mature embryos were cultivated on MS medium added at 2 different concentrations of 2.4-D in order to induce the callogenesis. The best results are retained for the culture of immature embryos. Differing parameters were considered: reaction of the scutellum, time of callus induction, area of calli, rate of callogenesis. A selective pressure (PEG) was applied to these calli during 30 days. Al calli were transferred on to regenerated medium. 4 types of calli were obtained from mature and immature embryos. The growth regulators are necessary for the development of roots (AIA+BAP) but inhibiting for the embryogénie calli. The immature embryos regenerate the most plants, however the mature embryos cultivated on the 2.4-D+AgN03 have the best performances of callogenesis. The regenerated seedlings present morphological variations relating to the size and the orientation of the foliage, and the vegetative cycle. These morphological variations appear since the stage callus through diversity of the growth of the calli, the morphological appearance, as well as the various answers of the cellular lines subjected to the PEG. We find these variations in the same genotype resulting from the same type of embryo. The durum wheat was shown more tolerant than the bread wheat. As for regeneration, the immature embryos seem made up the ideals expiants for regeneration like for obtaining tolerant plants.