It is particularly hard to create new MDBs that stay in class. This page seeks to enumerate the types of croses that have produced MDBs. These parentages would be possibility predictive of chromosome counts, and the genetic makeup of the cultivar. Modern MDBs started out as Iris pumila crosses, Early MDBs were usually Iris lutescens (chamaeiris). Standard Dwarf Bearded (SDB) were created by crossing pumila and tall bearded Irises. The following parentages are common in MDBs; pumila x pumila, MDB X pumila, pumila X MDB, MDB X MDB, SDB X MDB, MDB X SDB, SDB X SDB. Note pod parent is always listed first.
We are generating a list of cultivars in each phenotypic parentage
Predicted chromosome number (8 + 8 +8 + 8); 4n = 32chromosomes
pumila X pumila; 'Kochivnyk'
; 'Naletila Khmarka'
; 'Tsarytsia Amazonok'
; 'Vohni Na Kurhanakh'
MDB X pumila;
pumila X MDB; 'Royal Wonder'
; 'Storm Compass'
MDB X MDB; 'Sapphire Jubilee'
Predicted chromosome number (12 + 8 + 8 + 8); 4n = 36chromosomes
SDB X MDB;
MDB X SDB; 'Fancy This'
; 'Hot Tip'
Predicted chromosome number (12 + 8 +12 + 8); 4n = 40chromosomes
SDB X SDB; 'Beetlejuice'
; 'Black Olive'
; 'Dragon Flamedart'
; 'Droll Troll'
; 'Early Sunbeams'
; 'Little Jan'
pumila X TB: (8 + 8 +12 +12)
Unknown parents keep us from being sure of background but one might assume If the unknown bloomed at the same time as the pod parent it was probably the same class or possibly self fertilized.
pumila X ?;
MDB X ?;
SDB X ?; 'Celtic Pixie'
; 'Island Waters'
IB X ?; 'Misty Shores'
SDBs were created by crossing pumila X tetrapoid Tall-bearded. TB = (12 + 12 + 12 + 12) 4n=48
IBs were created by crossing SDB with Tetraploid TB. IB = (8 +12 + 12 +12) 4n=44
One of Mendel's Laws of inheritance assumes that each parent provides a full set of its chromosomes, which is why the above predictions might be made. But accidents do happen. pumilas should always have 4 sets of 8 chromosomes = 32 total. But occassionally a chromosome may get left behind or an extra go forward during division. Although this is rare one may find pumilas that upon counting have a count of 30, 31, or 33. Sometimes even plants of the same cultivar that have been growing distantly from each other may look the same but have counts that vary by 1 or 2. So the above predictions are only true most of the time and other factors should be considered. An unbalanced set of chromosomes is usually sterile or low fertility because the sets do not match up. The IBs originally 8 + 12 +12 +12 are an example. But nature has a way of compensating over time and now many IBs are fertile. If their chromosomes were counted they might well turn out to be 40 (8 + 8 +12 +12) or 48(12 + 12 +12 +12). So one can see the above categories are a simplistic approach.
The biggest flaw in looking at parentage this way should now be obvious. If an MDB is from two SDB parents, it should carry the same type of gene compliment as an SDB. But we call it an MDB and if we just look at the previous generation two MDBs crossed may actually be genotypically SDBs. Unfortunately to type the genotypes we must trace back all the way to the beginning of lineages to have a clear idea of the genotypes.
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Interested in MDB's?
Please visit the: Dwarf Bearded Iris Society
Your Observations Are Valued.
Please make note of bud count, branching, purple based foliage and bloom time, etc. Because these are affected by climate, note date, year and geographic location and write these and other comments in the comment box below.
-- Main.RPries - 2011-03-07