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12045RE: [AZ] 4ns and 2ns: Where We are Now

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  • SJPERK5
    Feb 2, 2009

      Mike, ONE MORE TIME

       

      Is there possibly a common ancestor azalea lurking in the in Aiken county SC ? More likely on a slope in the mountains of Georgia or a along a deep ravine that hasn’t been changed in the last 40,000 years,

      40,000 years is a long time to lurk in a constantly changing environment like the temperate climate of North America . So you want to find the primitive ancestor just looks for a location that hasn’t changed in the last 40, 000 years. The trees aren’t that old. Can’t say its not possible. Evolution happens much faster in the temperate regions than the tropics as there are just that many more climatic, biologic, geologic changes occurring (ice ages and massive floods etc). Just look at how major a change the balsam aldelgid, chestnut blight or hemlock adelgid have wrought to the forest populations in the last 100 years. Now throw in man’s intervention (dams, roads, development, flood control projects etc.)

       

      The early arborescens is self infertile. Is that so unusual?  Lots of deciduous azaleas are self infertile, not a bad idea if you want to make sure your descendents aren’t inbred. It’s usually not a good idea to inbreed if there are recessive fatal characteristics lurking in your genotype (i.e. hemophiliacs). Could the early arborescens be different enough to be a species or does the southern arborescens have some mix blood from viscosum messing up our keys?

       

      We have never NEVER, used pollen from a KNOWN 2n on a KNOWN 4n and gotten a fat seedpod, much less fertile offspring.

       

       In the past we may have thought that. How were we suppose to know that My Mary, Marydel, atlanticum…. were 4n?

      We believed the books and the registration.

      We had to accept on faith that unreduced gametes was happening all the time. That unreduced gametes might happen occasionally I will not rule out but I for one don’t believe that is what is happening and its certainly not the norm and I now just assume it’s rare.

      Rare works in the long scheme of things.  

       

      THE ONLY mixed crosses we have done are using pollen from a KNOWN 4n onto a KNOWN 2n stigma (the seed parent) and sure enough we can get some seed set, not every time as that is the nature of hand crosses. In the EASTERN North American species 4n stigma (seed parent) will not accept 2n pollen. .  2n stigma will accept 4n pollen with the result being seedpods full of 3n seeds that if grown on you can select some pretty nice 3n infertile (pollen and seed) plants.

       

       

      Occidentale just may be different and we are looking at probably speciation occurring as there are 2n and 4n populations of occidentaleShame that those species are fluid and changing all the time. I don’t grow occidentale or their hybrids so I can’t comment anymore than this.

       

      So much harder to put them in the keyholes we have. If the world would just stop changing we might be able to catch up. Fat chance. Go with it my friend Mike.

       

      Sally Perkins, Salem , NH

      actually got above freezing for a few hours yesterday and may again today.  

       


      From: azaleas@yahoogroups.com [mailto: azaleas@yahoogroups.com ] On Behalf Of Mike Creel
      Sent: Sunday, February 01, 2009 9:34 PM
      To: azaleas@yahoogroups.com
      Subject: Re: [AZ] 4ns and 2ns: Where We are Now

       

      John:

      Thank you for summarizing all this.  Is it possible that some of these "common ancestor" azaleas could exist in some isolated location as a living remnant ot artifact?  The isolated population of early-blooming arborescens from Aiken County , SC (which Woodlanders introduced and which I grow) is self-infertile, blooms in mid April (2 months before normal mountain forms of arborescens in my yard) and seems even smoother than typical arborescens.

       

      Didn't you say that you had pollinated 2n azaleas with a 4n calendulaceum and got fertile offspring?

       

      Isn't 4n calendulaceum regularly crossed with 2n occidentale?

       

      Mike Creel, SC



      --- On Sun, 2/1/09, sjperk5 <sjperk5@...> wrote:

      From: sjperk5 <sjperk5@...>
      Subject: [AZ] 4ns and 2ns: Where We are Now
      To: azaleas@yahoogroups.com
      Date: Sunday, February 1, 2009, 10:40 AM

      Two major findings occurred in deciduous azaleas since 2005.

      Dr. Ranney determined that several species thought to be 2ns are in
      fact 4ns.

      Dr. Hall determined that the 4ns species share a common ancestor, the
      2ns share a common ancestor, and that these ancestors are distinct. In
      others words the 2ns form one clade and the 4ns form a second distinct
      clade.

      Now some edges (exceptions) exist. One R. occidentale which is a 2n and
      is in the 2n clade has known populations of 4ns. Two R. canadense and
      R. molle (most likely) are 2ns but belong to the 4n clade. Three R.
      vaseyi a 2n belongs to neither the 2n clade or the 4n clade. Four there
      are a few nature hybrids that give the appearance of being crosses
      between 2ns and 4ns.

      A few people who have done hand crosses have found that 4n members of
      the 4n clade and 2n members of the 2n clade simply do not normally
      interact to produce fertile offspring but instead normally produce
      nothing or infertile 3ns which is consistent with the expected outcome
      of crossing 2ns and 4ns based on simple generics.

      My point is no matter what you think of the validity of any one of
      these findings, the findings from Ranney, Hall, and the people doing
      hand crosses support each other.

      John Perkins
      Salem , NH

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