Rhododendron 'Val d'Aulnay', which is a Croux and Fils hybrid, has been determined to be a triploid 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 'Val d'Aulnay' is the seed parent of 'L'Engin', which has been determined to be tetraploid. 'Lem's Cameo', which has been determined to be diploid, is the pollen parent of 'L'Engin'.
In the case of the tetraploid 'L'Engin', a triploid crossed with a diploid produced a tetraploid indicating that unreduced meiosis occurred for either the triploid 'Val d'Aulnay' or the diploid 'Lem's Cameo'. In other words, 'L'Engin' having 52 chromosomes either 1) received all 39 of 'Val d'Aulnay' chromosomes plus 13 from 'Lem's Cameo' or 2) received 26 from 'Val d'Aulnay' plus all 26 of 'Lem's Cameo' chromosomes.
Summary of Ploidy Levels
Diploid 'Lem's Cameo',
Triploid 'Val d'Aulnay',
Tetraploid L'Engin
Source Marc Colombel
John and Sally Perkins
