H: Wednesday, March 23, 2011

(cumberlandense X arborescens) X calendualceum is a Triploid

Two seedlings of [(Rhododendron cumberlandense X Rhododendron arborescens) X Rhododendron calendulaceum] have 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.

Rhododendron cumberlandense and Rhododendron arborescens are diploid species. Rhododendron calendulaceum is a tetraploid species.

In the case of these 2 triploids (39 chromosomes), a diploid crossed with a tetraploid produced a triploid indicating normal meiosis occurred where the diploid contributed a 1x gamete (13 chromosomes) and the tetraploid contributed a 2x gamete (26 chromosomes).

Summary of Ploidy Levels

Diploid Rhododendron cumberlandense,
Diploid Rhododendron arborescens,
Triploid 2 seedlings from [(Rhododendron cumberlandense X Rhododendron arborescens) X Rhododendron calendulaceum],
Tetraploid Rhododendron calendulaceum

Source: Joe Bruso

John and Sally Perkins
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