One seedlings of Rhododendron 'Horizon Monarch' open pollinated, which was raised by Marc Colombel, 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.
In the case of the tetraploid seedling of 'Horizon Monarch' open pollinated, a tetraploid seed parent produced a tetraploid indicating that normal meiosis most likely occurred for the tetraploid seed parent. In other words, the tetraploid seedling of 'Horizon Monarch' open pollinated having 52 chromosomes received 26 chromosomes from the tetraploid 'Horizon Monarch'.
Four seedlings were ploidy tested from seed collected by Marc Colombel from 'Horizon Monarch'. Three tested as diploid and one seedling tested as tetraploid. This indicates that the offspring of a given cross can have different ploidy levels from one offspring to another.
The 'Horizon Monarch' used to collect open pollinated seed by Marc Colombel ploidy tested as a tetraploid.
Summary of Ploidy Levels
Diploid 3 Seedlings of 'Horizon Monarch' open pollinated,
Tetraploid 1 Seedlings of 'Horizon Monarch' open pollinated,
Tetraploid 'Horizon Monarch'
Source Marc Colombel
John and Sally Perkins
