Rhododendron 'Lydia', which is a Harold Greer hybrid documented as 'Antoon van Welie' x 'Day Dream Group', 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.
'Lydia', which has 'Broughtonii', 'Pink Pearl', and 'Antoon van Welie' as ancestors, is the pollen parent of 'Grand Slam'. 'Trude Webster', which has 'Broughtonii', 'Pink Pearl', and 'Countess of Derby' as ancestors, is the seed parent of 'Grand Slam'.
Notice 'Grand Slam' represents the merging of 2 multi-generational polyploid lines, namely 1)'Broughtonii' (3x), 'Pink Pearl' (3x), 'Cynthia' (3x), 'Countess of Derby' (4x), 'Trude Webster' (4x), to 'Grand Slam' (4x) and 2)'Broughtonii' (3x), 'Pink Pearl' (3x), 'Antoon van Welie' (4x), Lydia (3x) to Grand Slam (4x).
Summary of Ploidy Levels
Triploid 'Broughtonii',
Triploid 'Cynthia',
Triploid 'Lydia',
Triploid 'Pink Pearl',
Tetraploid 'Grand Slam',
Tetraploid 'Antoon van Welie',
Tetraploid 'Countess of Derby',
Tetraploid 'Trude Webster'
Source: Greer Gardens
John and Sally Perkins
