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4ns and 2ns: Where We are Now

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  • sjperk5
    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
    Message 1 of 6 , Feb 1, 2009
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      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
    • sjperk5
      For many years the common belief, excluding canadense and vaseyi, was our native azaleas liked to cross with one another and produce fertile offspring. What
      Message 2 of 6 , Feb 1, 2009
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        For many years the common belief, excluding canadense and vaseyi, was
        our native azaleas liked to cross with one another and produce
        fertile offspring.

        What was interesting is R. calendulaceum a known 4n for a long time
        seemd to be able to produce fertile offspring in both directions with
        known 2ns. Now crossing 4ns and 2ns should usually produce nonfertile
        offspring but in native azaleas the literatures was full of
        documented cases of fertile offpring from such crosses being the norm.

        For years R. calendulaceum and R. austrinum have been crossed to
        produce fertile hybrids. Dodd, Aromni, Sommerville, and many others
        have produced numerous beautiful hybrids using this combination.

        The theory was R. calendulaceum had some magicial powers to make
        crosses with the 2n native azalea not result in nonfertile 3ns but
        instead fully fertile 4ns. This magic power had something to do with
        R. calendulaceum being merely a 4n R. cumberlandense or a special
        unreduced combination of R. cumberlandense and other native 2ns.

        Three events changed the thinking. Ranney showed using new counting
        technigues that austrinum and atlanticum where 4n. Hall showed that
        the 4ns and 2ns were at least in nature not crossing to any great
        extend but instead formed distinct clades. Hybridizers of native
        azaleas doing controlled crosses in the north and south were finding
        that 4n X 2n were almost never successful and that 2n X 4n seemed to
        usually produce infertile offspring.

        Hall showed that R. cumberlandense and R. calenducaleum are in fact
        not all that closely related. R. calenducaleum is more closely
        related to luteum, austrinum, atlanticum, colemanii, canadense, and
        molle than to any of the memebrs of the 2n clade including R.
        cumberlandense.

        So three different approaches to analyzing our native azaleas seem to
        have converged on instead of our native azaleas being one large
        interbreeding collection of species they are instead divided into 2
        clades along basically ploidy lines that are reluctant to share DNA
        across multiple generations.

        John Perkins
        Salem, NH
      • Mike Creel
        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
        Message 3 of 6 , Feb 1, 2009
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          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

        • William C. Miller III
          John, Regarding Ranney s findings: If you take another look at Jones, Ranney, Lynch, and Krebs, you will note that Ranney (ARS, Vol 61, No. 4, Fall 2007, pp
          Message 4 of 6 , Feb 1, 2009
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            John,

            Regarding Ranney's findings:  If you take another look at Jones, Ranney, Lynch, and Krebs, you will note that Ranney (ARS, Vol 61, No. 4,  Fall 2007,  pp 220-227) found austrinum to be 2n, 3n, and 4n using flow cytometry.  I think that's a significant finding given the relative small power of the sample size.

            If Hall selected a different sequence of the genome to evaluate, what is the possibility that an entirely different clade relationship might be revealed?

            Bill


            sjperk5 wrote:

            For many years the common belief, excluding canadense and vaseyi, was
            our native azaleas liked to cross with one another and produce
            fertile offspring.

            What was interesting is R. calendulaceum a known 4n for a long time
            seemd to be able to produce fertile offspring in both directions with
            known 2ns. Now crossing 4ns and 2ns should usually produce nonfertile
            offspring but in native azaleas the literatures was full of
            documented cases of fertile offpring from such crosses being the norm.

            For years R. calendulaceum and R. austrinum have been crossed to
            produce fertile hybrids. Dodd, Aromni, Sommerville, and many others
            have produced numerous beautiful hybrids using this combination.

            The theory was R. calendulaceum had some magicial powers to make
            crosses with the 2n native azalea not result in nonfertile 3ns but
            instead fully fertile 4ns. This magic power had something to do with
            R. calendulaceum being merely a 4n R. cumberlandense or a special
            unreduced combination of R. cumberlandense and other native 2ns.

            Three events changed the thinking. Ranney showed using new counting
            technigues that austrinum and atlanticum where 4n. Hall showed that
            the 4ns and 2ns were at least in nature not crossing to any great
            extend but instead formed distinct clades. Hybridizers of native
            azaleas doing controlled crosses in the north and south were finding
            that 4n X 2n were almost never successful and that 2n X 4n seemed to
            usually produce infertile offspring.

            Hall showed that R. cumberlandense and R. calenducaleum are in fact
            not all that closely related. R. calenducaleum is more closely
            related to luteum, austrinum, atlanticum, colemanii, canadense, and
            molle than to any of the memebrs of the 2n clade including R.
            cumberlandense.

            So three different approaches to analyzing our native azaleas seem to
            have converged on instead of our native azaleas being one large
            interbreeding collection of species they are instead divided into 2
            clades along basically ploidy lines that are reluctant to share DNA
            across multiple generations.

            John Perkins
            Salem, NH

          • SJPERK5
            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
            Message 5 of 6 , Feb 2, 2009
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              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

            • sjperk5
              Bill I respectively disagree with your position. Here is the paper on line http://www.lib.ncsu.edu/theses/available/etd-03112008- 225130/unrestricted/etd.pdf
              Message 6 of 6 , Feb 2, 2009
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                Bill

                I respectively disagree with your position.

                Here is the paper on line

                http://www.lib.ncsu.edu/theses/available/etd-03112008-
                225130/unrestricted/etd.pdf

                Here is the conclusion

                No diploid R. austrinum or R. atlanticum was found despite extensive
                sampling of taxa from diverse sources and geographical origins (26 R.
                austrinum and 30 R. atlanticum accessions collected throughout the
                Southeast). The assessment of these species as diploids in previous
                studies was based on a much more limited sampling (Ammal, 1950; Li,
                1957; Sax, 1930). Therefore it seems unlikely that the lack of
                diploid forms of R. atlanticum and R. austrinum in this survey
                represents a sampling limitation, but rather a predominance of
                polyploids in these species. This appears to be the case for R.
                calendulaceum as well, where there are no reports (present study
                included) of diploid populations.

                Now yes Ranney did find that some things called austrinum were 2n and
                3n but these are in my opinion and of the author are most likely not
                austrinum had instead have been previously misidentified. The 2n
                austrinmum came from the Biltmore Estate and the 3ns from the North
                Carolina Arboretum. No plants thought to be austrinum in a native
                population were anything but 4ns. The same was true of atlanticum.

                Note: There were also some 4n flammeum not collected in the wild.

                Note: But all of this has at least 3 major problems. One the
                definition of species is not very precise. Two nature is not so
                simple. Three and most importantly Ranney and Hall start by assuming
                that species are as previously outlined and then go from there.

                Despite these problems and the newness of the technigues employed it
                is my position that the 3 findings outlined previously are simply too
                supporting of one another to not be taken seriously.

                Evidence is evidence and conclusions are just that conclusions and
                you have every right to come to your own.

                John Perkins
                Salem, NH




                --- In azaleas@yahoogroups.com, "William C. Miller III" <bill@...>
                wrote:
                >
                > John,
                >
                > Regarding Ranney's findings: If you take another look at Jones,
                Ranney,
                > Lynch, and Krebs, you will note that Ranney (ARS, Vol 61, No. 4,
                Fall
                > 2007, pp 220-227) found /austrinum/ to be 2n, 3n, and 4n using
                flow
                > cytometry. I think that's a significant finding given the relative
                > small power of the sample size.
                >
                > If Hall selected a different sequence of the genome to evaluate,
                what is
                > the possibility that an entirely different clade relationship might
                be
                > revealed?
                >
                > Bill
                >
                >
                > sjperk5 wrote:
                > >
                > > For many years the common belief, excluding canadense and vaseyi,
                was
                > > our native azaleas liked to cross with one another and produce
                > > fertile offspring.
                > >
                > > What was interesting is R. calendulaceum a known 4n for a long
                time
                > > seemd to be able to produce fertile offspring in both directions
                with
                > > known 2ns. Now crossing 4ns and 2ns should usually produce
                nonfertile
                > > offspring but in native azaleas the literatures was full of
                > > documented cases of fertile offpring from such crosses being the
                norm.
                > >
                > > For years R. calendulaceum and R. austrinum have been crossed to
                > > produce fertile hybrids. Dodd, Aromni, Sommerville, and many
                others
                > > have produced numerous beautiful hybrids using this combination.
                > >
                > > The theory was R. calendulaceum had some magicial powers to make
                > > crosses with the 2n native azalea not result in nonfertile 3ns but
                > > instead fully fertile 4ns. This magic power had something to do
                with
                > > R. calendulaceum being merely a 4n R. cumberlandense or a special
                > > unreduced combination of R. cumberlandense and other native 2ns.
                > >
                > > Three events changed the thinking. Ranney showed using new
                counting
                > > technigues that austrinum and atlanticum where 4n. Hall showed
                that
                > > the 4ns and 2ns were at least in nature not crossing to any great
                > > extend but instead formed distinct clades. Hybridizers of native
                > > azaleas doing controlled crosses in the north and south were
                finding
                > > that 4n X 2n were almost never successful and that 2n X 4n seemed
                to
                > > usually produce infertile offspring.
                > >
                > > Hall showed that R. cumberlandense and R. calenducaleum are in
                fact
                > > not all that closely related. R. calenducaleum is more closely
                > > related to luteum, austrinum, atlanticum, colemanii, canadense,
                and
                > > molle than to any of the memebrs of the 2n clade including R.
                > > cumberlandense.
                > >
                > > So three different approaches to analyzing our native azaleas
                seem to
                > > have converged on instead of our native azaleas being one large
                > > interbreeding collection of species they are instead divided into
                2
                > > clades along basically ploidy lines that are reluctant to share
                DNA
                > > across multiple generations.
                > >
                > > John Perkins
                > > Salem, NH
                > >
                > >
                >
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