'Rendezvous' is a Diploid

Rhododendron 'Rendezvous', which is a Hachmann hybrid documented as 'Marinus Koster' X R. degronianum ssp. yakushimanum, 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.

The hybridization efforts by John and Sally Perkins indicated that 'Rendezvous' was most likely a diploid.

Rhododendron 'Marinus Koster', which was determined to be a tetraploid, is the seed parent of the diploid 'Rendezvous'. This seems to indicate that 'Marinus Koster' only provided 1x gamete (13 chromosomes) to 'Rendezvous'.

'Marinus Koster' is the pollen parent to 'Point Defiance', which was determined to be a tetraploid using flow cytometry by Dr. Thomas Ranney, J.R. Jones, and Nathan Lynch. 'Anna', which was determined to be a diploid, is the seed parent of 'Point Defiance'.

Summary of Ploidy Levels

Diploid 'Anna',
Diploid 'Rendezvous',
Tetraploid 'Marinus Koster',
Tetraploid 'Point Defiance'

Source: John and Sally Perkins

John and Sally Perkins

'Arneson's Gem' is a Tetraploid

Rhododendron 'Arneson's Gem', which appears to contain Rhododendron molle and an exbury azalea, 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.

The Perkins's Pollen Based Ploidy Test indicated that 'Arneson's Gem' was most likely a tetraploid.

Rhododendron 'Arneson's Gem' is pollen fertile but appears to be seed sterile. 'Chickasaw', which was found by Clarence Towe in the wild and was determined by Dr. Thomas Ranney and Nathan Lynch to be a tetraploid using flow cytometry, is seed fertile but produces no pollen.

These fertility issues may indicate that both of these tetraploid hybrids, one man made and the other occurring naturally in the wild, are aneuploids having a chromosome count near tetraploid.

Summary of Ploidy Levels

Diploid Rhododendron molle
Tetraploid 'Arneson's Gem'
Tetraploid 'Chickasaw'

Source: John and Sally Perkins

John and Sally Perkins

'Viscosepalum' is a Tetraploid

Rhododendron 'Viscosepalum', which is 1842 Waterer hybrid often documented to be Rhododendron molle X Rhododendron viscosum, 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.

The Perkins' Pollen Based Ploidy Test indicated than 'Viscosepalum' was most likely a tetraploid.

Since Rhododendron molle and Rhododendron viscosum are both diploid species, the documented parentage of 'Viscosepalum' is questionable.

Rhododendron 'Daviesii', which is also documented to be Rhododendron molle X Rhododendron viscosum and was breed in the same time frame as 'Viscosepalum', has been determined using flow cytometry to be a triploid.

Summary of Ploidy Levels

Diploid Rhododendron molle,
Diploid Rhododendron viscosum,
Triploid Rhododendron 'Daviesii',
Tetraploid Rhododendron atlanticum,
Tetraploid Rhododendron 'Viscosepalum'

Source: John and Sally Perkins

John and Sally Perkins

Audra State Park: A Ploidy Haven

Audra State Park, located in northwestern West Virginia, has been determined to contain diploid, triploid, and tetraploid deciduous azaleas 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.

Audra State Park contains the diploid species periclymenoides and arborescens and the tetraploid species calendulaceum. The three species have interacted to create nature hybrids some of which are triploids.

There are indications that Rhododendron prinophyllum may also be present. Rhododendron maximum and Kalmia latifolia are present.

Summary of Ploidy Levels

Diploid Rhododendron arborescens,
Diploid Rhododendron maximum,
Diploid Rhododendron periclymenoides,
Diploid Rhododendron prinophyllum,
Triploid Some deciduous azalea hybrids in Audra State Park,
Tetraploid Rhododendron calendulaceum

Source: Audra State Park

John and Sally Perkins

Triploids can be Fertile

'Gomer Waterer', 'Phyllis Korn', and 'August Lamken' have each been determined to be triploids 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.

Jim Barlup successfully used 'Phyllis Korn' as both a seed and parent parent. His 'Summer Peach' is a named crossed resulting from 'Phyllis Korn' as a pollen parent. His cross of 'Phyllis Korn' by 'Trude Webster' has produced viable offspring.

'Gomer Waterer' is documented to be the pollen parent of 'Phyllis Korn' which indicates that triploid offspring may result from a triploid pollen parent.

Werner Brack has grown open pollinated seed from 'Taurus', which was determined to be a triploid using flow cytometry by Dr. Thomas Ranney, J.R. Jones, and Nathan Lynch. Other hybridizers have found 'Taurus' to be both seed and pollen fertile. The Portugal research team has confirmed that Werner Brack's 'Taurus' is indeed a triploid.

Summary of Fertile Triploids

'Anna Rose Whitney',
'Betty Wormald',
'Broughtonii',
'Cynthia',
'Cotton Candy',
'Gomer Waterer',
'Lydia',
'Platinum Pearl',
'Phyllis Korn',
'Pink Pearl',
'Rwain',
'Taurus',
'Val d'Aulnay'

John and Sally Perkins

'Marie Hoffman' is a Diploid

Rhododendron 'Marie Hoffman' Picture by Henk Borsje

Rhododendron 'Marie Hoffman', which is often documented as a tetraploid form of Rhododendron prinophyllum, 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.

The nontypical Rhododendron prinophyllum characteristics of 'Marie Hoffman' are most likely due to hybridization with Rhododendron molle. 'Marie Hoffman', also, demonstrates the mule like fertility characteristics associated with most hybrids containing the combination of Rhododendron prinophyllum and Rhododendron molle

Summary of Ploidy Levels

Diploid 'Marie Hoffman',
Diploid Rhododendron molle,
Diploid Rhododendron prinophyllum

Source: John and Sally Perkins

John and Sally Perkins

Reminder: Massachusetts Chapter Meeting @ Sun Sep 26 1:30pm - 3:30pm (ARS Massachusetts Chapter Calendar)

more details » Massachusetts Chapter Meeting Meeting When Sun Sep 26 1:30pm – 3:30pm Eastern Time Where Elm Bank Wellsley, MA (map) Calendar ARS Massachusetts Chapter Calendar Who • John Perkins - creator

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Reminder: Board Meeting @ Wed Sep 8 7:30pm - 9pm (ARS Massachusetts Chapter Calendar)

more details » Board Meeting When Wed Sep 8 7:30pm – 9pm Eastern Time Where Hardings (map) Calendar ARS Massachusetts Chapter Calendar Who • John Perkins - creator

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ARS Mass Chapter Newsletter

Attached is the September Newsletter, courtesy of our hard working Newsletter Editor Susan Clark, to whom we should all be grateful.

 

The Newsletter contains important information on upcoming events. 

I want to draw your attention to one event: the Donated Plants Sale.  Please bring to this sale any extra plants you have that need a new home.  Rhododendrons are most preferred, but we always find homes for many companion plants, shrubs & trees as well.

 

Special Notice:  P4M will not have any meetings in September.  The next meeting will be October 23.  Contact the P4M co-chairs (John Perkins and Fred Knippel) for more information.

Joe Bruso

Reminder: Board Meeting @ Wed Sep 8 7:30pm - 9pm (ARS Massachusetts Chapter Calendar)

more details » Board Meeting When Wed Sep 8 7:30pm – 9pm Eastern Time Where Hardings (map) Calendar ARS Massachusetts Chapter Calendar Who • John Perkins - creator

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