Combating Dutch Elm Disease

New research into a previously hidden population of elms shows the trees carry genes resistant to Dutch elm disease, which continues to affect U.S. trees.

Diploid elms - elm trees with only two copies of chromosomes - have been found by themselves and intermixed with the expected tetraploid elms (four copies of chromosomes).
Diploid elms - elm trees with only two copies of chromosomes - have been found by themselves and intermixed with the expected tetraploid elms (four copies of chromosomes).
courtesy Agricultural Research Service