'El Camino' is a Triploid

Rhododendron 'El Camino', which is a William Whitney hybrid documented as 'Anna' x 'Marinus Koster', 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 the triploid 'El Camino', a diploid crossed with a tetraploid produced a triploid indicating that reduced meiosis most likely occurred for both parents. In other words, 'El Camino' having 39 chromosomes received something similar to 13 chromosomes from the diploid 'Anna' and 26 chromosomes from the tetraploid 'Marinus Koster'.

Summary of Ploidy Levels

Diploid 'Anna',
Diploid 'Norman Gill',
Diploid 'The Honourable Jean Marie de Montague',
Triploid 'El Camino',
Tetraploid 'Lem's Monarch',
Tetraploid 'Marinus Koster',
Tetraploid 'Pink Walloper',
Tetraploid 'Point Defiance',
Tetraploid 'Walloper No. 10'

Source Marc Colombel

John and Sally Perkins

'Hurricane' is a Diploid

Rhododendron 'Hurricane', which is a William Whitney hybrid documented as 'Mrs Furnivall' x 'Anna Rose Whitney', has been determined to be a diploid 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 'Hurricane' has as ancestors 'Broughtonii', 'Cynthia', 'Pink Pearl', 'Countess of Derby', 'Mrs Furnivall', and 'Anna Rose Whitney'.

In the case of 'Hurricane', a diploid 'Mrs. Furnivall' crossed with a triploid 'Anna Rose Whitney' produced a diploid indicating 'Anna Rose Whitney' most likely contributed only a 1x gamete (13 chromosomes) to 'Hurricane'.

Summary of Ploidy Levels

Diploid 'Hurricane',
Diploid 'Mrs. Furnivall',
Triploid 'Anna Rose Whitney',
Triploid 'Broughtonii',
Triploid 'Cynthia',
Triploid 'Pink Pearl',
Tetraploid 'Countess of Derby'

Source: Whitney Nursery

John and Sally Perkins