Re: transitive properties of hybridizing

 

Am 15.06.2013 17:22, schrieb Sean Zera:
I don't think chromosome counts are that important; better to simply know what's considered related to what. Most of the beardless crosses are being done between the series Laevigatae, Sibericae, Chrysographes/Californicae and Tripetalae, which form a clade in the genetic work that's been done. Probably any of them can be crossed if you try long enough.

I assume ensata should be able to be crossed with siberians. I. tridentata is closely related to setosa, which has been crossed with versicolor. Tamberg produced versitosas with tetraploid setosa, but I assume the diploid cross is possible, just harder to make - it's basically like a ×robusta. I can't see why tridentata wouldn't work as well.

Sean Z
Sean, et al,

although there is always the possibility to get the occasisional wide cross, which Tomas Tamberg (amongst others) has proved quite a few times, continuing is almost always impossible on the diploid level, as the chromosome groups so created cannot go through a fertile meiosis, hence the need to create an artificial tetraploid/polyploid, which then allow the chromosomes to pair properly during meiosis.  This is the same problem we have with aril/TB crosses.  They work, but are generally incapable of progeny as diploids.  As we know, there have been exceptions, but no truly fertile diploid progeny from aril/TB crosses.

As we seem to have a great deal of inconsistency in chromosome counts of related species (as in the series you mentioned), one would expect they are actually the evolution of early natural hybrids, maybe even spontaenious mutations  (hmmm, evolution!).  The pseudatas, which do not occur in the wild as far as we know, are the result of a mutation in a pseudacorus clone, Gibujin, allowing it to hybridise with ensata. Theoretically, this could happen in the wilds.  In short, it is possible, just extremely time consuming, which, for humans, with their limited lifespans, makes it frustrating.  Nature has eternity.

In the end, just try it.

-- 
Jamie V.

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