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16051Re: Strange R. occidentale article

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  • sjperk5
    Mar 1, 2011
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      We talk about superreduced neotetraploids here.

      http://rosebayblog.blogspot.com/search/label/Superreduced

      This is documentd to occur in other genus also.

      The fact that it has occurred for Horizon Monarch as a seed parent where the tetraploid seed parent and multiple seedlings from the tetraploid have been tested as diploid is pretty strong evidence this can happen in the genus Rhododendron. We tested the actual 'Horizon Monarch' plant that produced these diploid seedlings.

      Ranney's lab testing of SM 232 x `Double Dig Twelve' as diploid seems to indicate that 2x X 4x can produce 2x for neotetraploid deciduous azaleas also.

      John Perkins
      Salem, NH

      --- In azaleas@yahoogroups.com, "sjperk5" <sjperk5@...> wrote:
      >
      > SM 232 x `Double Dig Twelve' testing as diploid assuming we accept the cross was true indicates that `Double Dig Twelve' is a neotetraploids and is therefore able to under go superreduction. This is even more support for R. occidentale being a diploid species. In other words both parents contributed 13 chromosomes rather than expected 26 you normally get form a tetraploid pollen parent.
      >
      > We have seen this with neotetraploid hybrid elepidotes. We have evidence of this even when the seed parent is the neotetraploid.
      >
      > To date we have not seen superreduciton occur for a tetraploid native deciduous azalea species.
      >
      > John Perkins
      > Salem, NH
      >
      > --- In azaleas@yahoogroups.com, "occidentale" <red@> wrote:
      > >
      > > I collected sample material for both Hall and Ranney from SW Oregon, NW California and the Mt. Palomar area of Southern California. I also sent the material from cutting grown plants in my garden. Mike McCullough also sent Tom material. His email of 8-31-09 is below. I can send the spread sheet if anyone wants it. There are 44 R. occidentale, one natural hybrid and one R. macro.
      > >
      > > I will be doing a program at the Convention in May, R. occidentale An Outlaw species. I have about 60 photos of flowers no two of which are the same. I would encourage you to attend.
      > >
      > > Dick 'Red' Cavender, Red's Rhodies, Sherwood Oregon USA Zone 8
      > >
      > > Red and others,
      > >
      > > Nathan ran the occidentale samples, spreadsheet attached. In general, they were all diploids with the exception of 'Double Dig Twelve' (4x) and SM 502 (3x). SM 232 x 'Double Dig Twelve' was diploid, suggesting a possible paternity suit.
      > >
      > > A number of samples (the ones with a * in column 2) had some tissue with higher ploidy levels in the floral buds. For example Braaflad Twisted Petals was 2x, 4x, and 8x in the floral tissue. In cases where we had vegetative buds, from the same plant, they were just diploid. This suggests that there is some endoreduplication going on in the floral tissue. This has been reported in evergreen azaleas before and it was found that floral tissues with different ploidy levels actually had different colors and gave rise to picotees. This could contribute to things like twisted petals and varied flower colors in occidentale.
      > >
      > > I think we have pretty good evidence now that R. occidentale is primarily a diploid taxa.
      > >
      > > Tom
      > >
      >
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