Rhododendron 'Graf Zeppelin', which is a C. B. Van Nes hybrid documented as 'Pink Pearl' x 'Mrs. Charles S. Sargent', has been determined to be a diploid using flow cytometry by
Dr. João Loureiro, Dr. Silvia Castro, José Cerca, and Mariana Castro
Plant Ecology and Evolution Group,
Centre for Functional Ecology,
Department of Life Sciences,
Faculty of Science and Technology,
University of Coimbra, Portugal.
Rhododendron 'Graf Zeppelin' has as ancestors 'Broughtonii' and 'Pink Pearl' which are both triploids.
Summary of Ploidy Levels
Diploid 'Graf Zeppelin',
Triploid 'Broughtonii',
Triploid 'Pink Pearl'
Source: Van Veen Nursery
Source: Whitney Nursery
John and Sally Perkins
