Re: Re: inducing tetraploidy

 

Fiddlesticks!  That means my "Science of Spec-X" section is wrong.  :-/  In section 5, I wrote:

(5) Chromosome Count - If two species have different chromosome counts, fertilization can fail at the cellular level. This is a complex issue and it is the biggest barrier for making Spec-X hybrids. It is also the reason why Spec-X irises are so exciting! Diploid species will rarely hybridize if the chromosome counts don't match. Using tetraploid parents will improve your chances of success, but obtaining tetraploid parents is no simple task. Even if you can achieve a diploid seedling, it will likely be sterile due to the unbalanced chromosomes. Tetraploid offspring are more likely to be fertile.

Could you check out the whole page and send me your critiques?  I obviously need to re-write some stuff.

http://www.signa.org/index.pl?SpecXscience

Thanks,
Dennis in Cincinnati (where the temps are ALMOST bearable again)




On Tue, Jan 7, 2014 at 5:17 PM, Chuck Chapman <i*@aim.com> wrote:
If  chromosomes are  so incompatible as to not be able to pair up to
give a viable species,  they can't do it.  Two sets  of  chromosomes
can't pair with  two other sets of incompatible chromosomes any better.


Where the difference comes in is that if an incompatible set is able to
pair up , produce a viable offspring,. this organism isn't able to form
gametes from meiosis and so is sterile. If there are two sets, there is
an amphidiploid and pairing  and formation of viable gametes is
possible.

Tetraploidy is a solution for sterility, not for viability.


Chuck Chapman

-----Original Message-----
From: Dennis Kramb <d*@badbear.com>
To: iris-species <i*@yahoogroups.com>
Sent: Tue, Jan 7, 2014 3:09 pm
Subject: Re: [iris-species] Re: inducing tetraploidy

 
Chuck, perhaps I've misunderstood, but I thought the theory was if two
wide species won't cross as diploids, they might as tetraploids.  (For
example, Little Caillet.)

Regardless, I'm going to attempt conversions on:  tridentata, fulva,
prismatica, and tectorum.  And possibly:  wilsonii, and black
chrysographes if I can find them.


The Oryzalin technique I'm going to follow had approx 10% success rate
with Watsonia sp.


Thanks to everyone for the tons of feedback & support I got on this
endeavor.


Dennis in Cincinnati




On Mon, Jan 6, 2014 at 9:55 AM, Chuck Chapman
&lt;irischapman@aim.com&gt; wrote:
Tetraploids are often (usually) fertile.  Diploids are never fertile on
wide crosses. If tertraploids set seed, then so will diploids.  If the
diploid corosses don't set seed, then the genes don't match up well
enough and having tetraploids  is very unlikely to make a difference.

If you make a diploid cross and get seeds, it is easy to treat seeds at
time of germination and get tetraploids. MMuch easier to treat
germinating seeds then converting a plant.

Chuck Chapman














------------------------------------

Yahoo Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/iris-species/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/iris-species/join
    (Yahoo! ID required)

<*> To change settings via email:
    i*@yahoogroups.com
    i*@yahoogroups.com

<*> To unsubscribe from this group, send an email to:
    i*@yahoogroups.com

<*> Your use of Yahoo Groups is subject to:
    http://info.yahoo.com/legal/us/yahoo/utos/terms/


Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index