In vitro culture of ovules ofTriticum aestivum at early stages of embryogenesis.

Because most of the intergenericGramineae embryos abort before they can be isolated and cultured, our object was to grow ovules at an early stage of embryogenesis. Ovules were at size 1 to 7 mm. The youngest stages represented ovules containing several-celled proembryos; the oldest stage consisted of embryos at the level of differentiation of the organs. 1357 ovules were jointly inoculated in 12 different media of which only 3 appeared to be most suitable for the growth and differentiation of globular proembryos. From several-celled proembryos (ovules at the size of 1.5 - 2.5 mm) only compact calluses developed. The capability of proembryos to differentiate and to form fully developed embryos and consequently plants started when the ovules were inoculated at the size of 2.5 - 3.0 mm. Since the medium plays an important role in the process of differentiation of proembryos, the application of similar culture conditions is suggested for the in vitro culture of haploid or hybrid proembryos obtained among wide crosses inGramineae.