CMS Hybrids are prohibited

No hybrid seeds created using protoplast or cytoplast fusion techniques may be used on Demeter certified (biodynamic) farms and gardens

For the reasoning behind the decision agreed by Demeter International in July 2005 read
PDF  Seeds of Concern written for the BDAA Newsheet by Peter Brinch.

Although Demeter producers are required to use biodynamic or organic seeds, it may happen that no organic seeds are available for a particular variety.When this occurs a derogation may be given by the organic certification body. This allows a producer to buy untreated but conventionally grown seeds.

Unfortunately there are fewer and fewer open pollinated varieties available and conventional plant breeders almost exclusively produce hybrids which today are CMS hybrids.

For those growers who are granted a derogation to use non-organic seed, it is often difficult to avoid CMS hybrids since they are not always labelled as such. The following list has therefore been put together by the  Forschungsring (the biodynamic research association in Germany) so that growers can know which vegetable varieties to avoid.

PDF  Click here for list 
DOC  A Call to Prohibit CMS protoplast fusion hybrids in Organic Food Production