Amelioration of somatic embryogenesis from immature embryos of wheat cultivars (Triticum aestivum L.).: I -: Effect of the developmental stage of embryos

The wheat immature embryos are often taken 14 days after the anthesis. At this age, the embryos size vary from 1 to 2 mm. The incubation of these embryos in the MS (1962) solid medium with 2 mg/l of 2,4-D show a genotypic effect to in vitro culture capacity. In order to study the effect of developmental stage of embryos on this capacity, two cultivars (Jouda and Saada) considered as recalcitrant and two others varieties which present a good capacity taken as control (Potam and Marchouch) are chosen. The culture of embryos at early stages (size less than 1 mm in lengh) permit to improve the embryogenesis capacity, the regeneration ability and the mean number of regenerated plantlets/morphogenesis callus. This improvement is more effective in the case of the recalcitrant varieties. On the contrary, at the late stages (size more than 2 mm), the embryos put into medium culture tend rather to germinate for all varieties.