Amphidiploid Arilbreds

Iris 'Concerto Grosso'Early arilbred breeding, which focused on crossing diploid oncocycli with diploid or tetraploid tall beardeds, was greatly hampered by the sterility of most of the progeny, not to mention difficulties in making the crosses and germinating the seeds. Except for an occasional break, such as 'Ib-Mac' or 'Capitola', in which a fertile amphidiploid was produced fortuitously, there was little opportunity to breed the arilbreds for desired qualities.

This situation eventually changed when C. G. White produced a family of fertile amphidiploid arilbreds, with two sets of aril chromosomes and two sets of tall bearded chromosomes. He did not keep breeding records, so we cannot be certain how this was accomplished. When an enormous number of seedlings are raised, some amphidiploids will be produced from unreduced gametes or other chromosome anomalies. Most modern arilbreds are descended from the C. G. White amphidiploids. Most "halfbreds" are members of this fertile family, while those less or more than half aril are typically infertile or of limited fertility.

This family can be expanded by crossing the tetraploid arils with the 48-chromosome bearded irises. This is important for expanding the genetic base of both the aril and the bearded component. The arils used in White's breeding were advanced generation oncogelias and oncocyclus hybrids, which he renewed annually from seed. Some species were doubtless more strongly represented in this mix than others. The "onco look" will always be a desirable trait in arilbreds, but recent fertile arilbreds from regelia breeding are also interesting and desirable plants. On the bearded side, C. G. White's arilbreds stem from early 20th-century TBs. Using modern TBs and BBs should produce improved arilbreds, contributing modern form, substance, and branching to the mix. If the 48-chromosome dwarfs and medians are used, fully fertile arilbred medians result. Harald Mathes's 'Anacrusis' and its descendents are examples of such breeding.

I plan to focus my work with this family on fertile arilbred medians, including regeliabreds.

 

Hall of Fame

Ib-Mac (C. G. Van Tubergen, BRS). AB/OB , MB. Medium red bitoned blend. I. iberica x I. macrantha. Van Tubergen, 1910. [44 chr.]

The first known amphidiploid arilbred, resulting from an unreduced gamete from I. iberica.

Capitola (Frank Reinelt, R. 1940). AB/OB, IMB, medium height, E. Dark red violet. William Mohr x Ib-Mac. 1940. [43 chr.]

'Ib-Mac's pollen-fertile offspring, once again thanks to an unreduced gamete from the pod parent. 'Capitola' was widely used in breeding, although mostly with TBs to produce the quarterbred "Mohrs", there being few other fertile arilbreds at the time to cross it with.

Kalifa Gulnare (Clarence G. White, R. 1954). Sdlg. 23B54. AB/OGB , EC, 34” (86 cm), E. S. pale orchid lavender; F. same, heavily overlaid apricot buff. Parentage unknown. Craig, 1955. [44 chr.]

Of the many important fertile amphidiploid arilbreds produced by C. G. White in the 1950s, I selected 'Kalifa Gulnare' for this list because of its almost ubiquitous presence in the pedigree of the modern arilbreds, and its relative longevity as a popular garden iris through the decades.

Welcome Reward (Eugene Sundt by Lois Rich, R. 1971). Sdlg. S59119. AB/OB , 27" (69 cm), L. S. lilac veined deeper, bronze flush part way up rib; F. gold bronze, haft veined mahogany on gold, pinkish flush on lower half; dark brown signal; golden brown beard; gold style crests. Austin W142-O (onco interspecies) x Pink Formal. Aril Society, 1971. [44chr]

While almost all fertile amphidiploid arilbreds in recent decades derive from the C. G. White varieties, 'Welcome Reward' is an exception: an amphidiploid oncobred of known parentage, resulting from an unreduced gamete from its oncocyclus pod parent. It has produced many important descendants.

Genetic Artist (Henry Danielson, R. 1971). Sdlg. F-66-1. AB/RB , 30” (76 cm), EM. Odd combination of bronzy yellow and blue; center of petals to sides of ribs metallic lavender blue; edges strongly colored red bronze with tints of henna; beard lavender. Frost and Flame x Vulcanus. Mount Clare Iris Gardens, 1972.

An alter ego to 'Welcome Reward', if you will, is 'Genetic Artist', an amphidiploid regeliabred with many interesting descendants. While it is easy to focus on oncocyclus qualities as the object of arilbred breeding, this spendidly colored iris reminds us that the Regelias also have unique colors, patterns, and forms to contribute to the mix.

Anacrusis (Harald Mathes, R. 1992). Sdlg. 88-MDB16. AB/OGB/ABM, 20” (51 cm), E. Oxblood red; red black signal and beards. Dresden Gold x T-IAM: ((I. iberica x I. auranitica) x I. suaveolens (mellita)). Aril Society, 1992.

The pollen parent is a colchicine-induced tetraploid whose bearded ancestry comes entirely from the miniature dwarf species I. suaveolens. This represents the first significant incorporation into the fertile arilbred family of bearded iris genes that are not from the garden TBs. 'Anacrusis' and its descendants are indeed of median height, and there is great potential here for launching a family of fertile arilbred medians. Its descendant 'Concerto Grosso' won the C. G. White Medal in 2005.

 

Gallery

 

'Noble Warrior' (Tasco, 2006)

'Iridescent Orange' (Mathes, 2001)

'Stars Over Chicago' (H. Danielson, 1972)
'Rare Breed' (Tasco, 2011)
'Anacrusis' (Mathes, 1992)
'Navajo Velvet' (McAllister, 2009)
'Alakazam'
(Tasco, 2013)
'Shaman's Magic'
(Tasco, 2014)
'Silent Sentry'
(Tasco, 2008)

Plant List

The list below shows the name of each plant I currently grow for breeding purposes, the source, and the year acquired.

Alakazam

Superstition Iris Gardens

2013

Anacrusis

Malevil Iris Gardens and SFIS

2011

Aztec Prince

Superstition Iris Gardens

2014

Bhutan

Superstition Iris Gardens

2013

Concerto Grosso

ASI

2011

Iridescent Orange

Malevil Iris Gardens

2011

Jonnye's Magic

Superstition Iris Gardens

2012

Navajo Velvet

Malevil Iris Gardens

2010

Noble Warrior

Superstition Iris Gardens

2011

Rare Breed

Superstition Iris Gardens

2011

Refiner's Fire

Superstition Iris Gardens

2012

Sand Dancer

Superstition Iris Gardens

2012

Shaman's Magic

Superstition Iris Gardens

2014

Silent Sentry

Superstition Iris Gardens

2014

Speckled Veil

ASI

2012

Tactical Diversion

ASI

2012

Wadi Safra Moonlight

ASI

2011

Illustration: 'Concerto Grosso' (Mathes '98): an amphidiploid arilbred from Mathes's 'Anacrusis' line.

 

Tom Waters

September 2010

updated May 2017

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Unless otherwise noted, all text and illustrations copyright Tom Waters and all photographs copyright Tom or Karen Waters. Please do not reproduce without permission.