Microspore culture of Hordeum vulgare L.: the influence of density and osmolality.

Donor plants of Hordeum vulgare L. cv. Igri were grown in a conditioned environment to minimise fluctuations in the composition of the microspore population. After isolation different types of microspores were identified within each population, amongst others an embryogenic subpopulation. It was shown that the optimum plating density is achieved by adjusting the density to 2×10(4) embryogenic microspores per ml, with a lower threshold at 5×10(3) per ml. By increasing the osmolality of the pretreatment solution to 440 mOs.kg(-1) and that of the culture medium to 350 mOs.kg(-1), up to 15% of the population developed into embryo-like structures. When microspores of cv. Igri were cultured under the optimized conditions, the ratio of green/albino plants increased from 1∶1 to 34∶1, and 50 green plants per anther were formed.