Biodynamic agriculture has focused on open pollination of seeds (permitting farmers to grow their own seed) and the development of locally adapted varieties.

Biodynamic agriculture has focused on the open pollination of seeds (with farmers thereby generally growing their own seed) and the development of locally adapted varieties.

The resulting hybrid strain can sometimes be inbred and selected for desired traits until a strain that breeds true by open pollination can be developed.

One of the bigger challenges in maintaining a strain by open pollination is avoiding introduction of pollen from other strains.

Diurnal pollination by large bees results in significantly less seed set than nocturnal and open pollination.

The hybrid has since arisen on nearly 20 separate occasions, always by open pollination, showing the two species are readily compatible and closely related.

In addition to being more physically uniform, hybrid corn produces dramatically higher yields than corn produced by open pollination.

"With open pollination you let the birds and bees do it," Mr. Mickilowski said.

However, they are known to eradicate domestic honeybee hives, resulting in fewer honeybees for open pollination.

With open pollination, some genetic diversity always shows up.