A seedling of 'Voluptuous' x 'Point Defiance', which is a Werner Brack 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.
In the case of this triploid seedling of 'Voluptuous' x 'Point Defiance', a diploid crossed with a tetraploid produced a triploid indicating that normal reduced meiosis most likely occurred for both parents. In other words, the triploid seedling having 39 chromosomes received 13 chromosomes from the diploid 'Voluptuous' and 26 chromosomes from the tetraploid 'Point Defiance'. Tetraploids usually contribute 26 chromosomes to their offspring.
Three seedlings were ploidy tested from the Brack cross of 'Voluptuous' x 'Point Defiance'. 'Orange Leopard' and 'Stony Brook' tested as diploid. This unnamed seedling tested as triploid. This indicates that the offspring of a given cross can have different ploidy levels from one offspring to another.
Summary of Ploidy Levels
Diploid 'Orange Leopard',
Diploid 'Stony Brook',
Diploid 'Voluptuous',
Triploid Seedling of 'Voluptuous' x 'Point Defiance',
Tetraploid 'Point Defiance'
Source: Werner Brack
John and Sally Perkins
