Rhododendron 'Point Defiance', which is a Halfdan Lem hybrid documented as 'Anna' x 'Marinus Koster', has been determined to be a tetraploid 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 'Point Defiance' has as descendants 'Doreen Gale', 'Gentle Giant', 'Horizon Monarch', 'Julia Caroline', 'Lady of Spain', 'Orange Leopard', and 'Stony Brook'.
In the case of the tetraploid 'Point Defiance', a diploid crossed with a tetraploid produced a tetraploid indicating that unreduced meiosis may have occurred for the diploid parent. In other words, 'Point Defiance' having 52 chromosomes received something similar to 26 chromosomes from the diploid 'Anna' and 26 chromosomes from the tetraploid 'Marinus Koster'.
Rhododendron 'Point Defiance' was also determined to be a tetraploid using flow cytometry by Dr. Thomas Ranney, J.R. Jones, and Nathan Lynch.
Summary of Ploidy Levels
Diploid 'Anna',
Diploid 'Horizon Lakeside',
Diploid 'Nancy Evans',
Diploid 'Norman Gill',
Diploid 'Orange Leopard',
Diploid 'Stony Brook',
Diploid 'The Honourable Jean Marie de Montague',
Triploid 'El Camino',
Triploid 'Julia Caroline',
Triploid 'Lady of Spain',
Triploid 'Platinum Pearl',
Tetraploid 'Doreen Gale',
Tetraploid 'Gentle Giant',
Tetraploid 'Horizon Monarch',
Tetraploid 'Lem's Monarch',
Tetraploid 'Marinus Koster',
Tetraploid 'Pink Walloper',
Tetraploid 'Point Defiance',
Tetrsploid 'Trude Webster',
Tetraploid 'Walloper No. 10'
Source: Greer Gardens
John and Sally Perkins
