According to the invention an embryogenic cell mass is cultured with a
culture medium comprising an anti-auxin resulting in an unexpected shift in physiology
from proliferation to maturation. Proliferation is reduced so that the formation
of new immature embryos ceases. Reduction of proliferation facilitates the transition
from proliferation to maturation and maturation frequency is increased to a much
larger extend than expected. Surprisingly, it has been discovered that the quality
of the somatic embryos is not reduced, although the activity of the important endogenous
plant growth regulator, auxin, is reduced. As a mater of fact, the overall quality
of the mature embryos harvested at the end of maturation is actually increased
over the prior art.
