ABB - AABB Crosses

ABB - AABB Crosses

Updated: 15 May, 2002 Returning? Jump to Photos

This page presents seedlings obtained by crossing an AAB-type triploid with an AABB-type halfbred. These have the potential for producing offspring of two genetically different types and this must be taken into account in evaluating their seedlings.

Tell me more about the nomenclature....

A cross between an ABB-type triploid and an AABB-type amphidiploid can produce both AAB-type triploids and AABB-type amphidiploids. The former qualify as quarterbreds (OB-, RB-, or OGB- under the current classification system) but the latter as halfbreds so for the purpose of registration it is necessary to determine which group a specific seedling belongs to.

If you are tempted by these types of crosses (and I certainly am!) you should be aware that many of the progeny will be very difficult to classify within the current criteria. Theoretically, a set of such seedlings should segregate neatly into two groups -- but real life is a bit more complicated. In practice, I have found that:

Many will look like and breed like halfbreds (OB, RB, or OGB).

Many will look like and breed like quarterbreds (OB-, RB-, or OGB-).

Some will look more like halfbreds but breed more like quarterbreds.

Some will look more like quarterbreds but breed more like halfbreds.

Some will be intermediate in both appearance and breeding behavior.

Although the first two groups are relatively easy to classify, the others provide a significant challenge and the present classification system effectively precludes introduction of those with intermediate traits.

Click on the thumbnail to see a larger version of a photo.

These date to the period in which I numbered crosses when I lined out the seedlings and seedlings when they were selected to save for further evaluation and possible introduction. The numbers are therefore no indication of the number of crosses made or the number of seedlings produced by each cross.

89-15: (Lovely Blanche x Eunice) X Sunrise in Glory. Go to Sibling Sheet for more details.
	89-15-1. Introduced as DRESS PINKS. Strong performer, enough ruffling to appeal to those who like that touch in their quarterbreds. Fertile enough to suggest that it's a triploid, pink enough to suggest it's a tetraploid -- but in either case it offers significant potential for the production of t-factor (tangerine) pink arilbreds.
	89-15-5. Striking colors, remarkably sunfast, good substance, excellent bud count. Probably a functional halfbred and it came very close to being introduced, but tests were inconclusive.

Hybridizing Terminology. You won't find these terms in official classification systems, but will see them in articles written by such well-known hybridizers as Tom Wilkes and John Holden. "A" simply stands for a set of aril chromosomes and "B" for a set of non-aril chromosomes. Fractions were sometimes used to depict the number of sets of aril chromosomes and the total number of sets. An AAB-type triploid might thus be called a "2/3-bred", while "2/4" would indicate a halfbred with two sets of aril chromosomes and two sets of non-aril chromosomes, and "1/2" would stand for a diploid with one set of aril chromosomes and one set of non-aril chromosomes. These terms were once widely used by hybridizers, but fell out of favor after the Aril Society adopted the Modified Chromosome-set Classification System but retained the nomenclature from the older Quantum System. Today, "1/2" usually means a fully fertile halfbred with two sets of aril and two sets of non-aril chromosomes. I have used the old-style hybridizers' terminology here, because it is not possible to accurately determine the correct classification code for seedlings of this type without extensive test crosses.