HYB:embryo rescue

 From: christian foster <_flatnflashy@yahoo.com_ 
(f*@yahoo.com) >  Date: Tue, 15 Aug 2006
 
 suspect that RHYTHM and or LITTLE FREAK may be diploid.   Does anyone know 
for sure?

I was digging around in  the archives trying to find any mention of sucessful 
tetraploid X diploid  crosses and stumbled upon mention of something called 
"embryo rescue".  

It seems that the endosperm of a seed is created  through a genetic process 
which is seperate from the process that creates the  embryo itself.  This means 
that a genetically viable embryo may be  sabotaged in its quest for 
germination by a genetically inviable  endosperm.  These seeds are characteristically 
the ones that collapse,  which is what all of my seeds from LF or R have done.  
(ever so much more  frustrating since they both set a pod if you look at them 
 crosseyed.)

Anyway, there is an embryo rescue  technique which might be manageable in a 
home environment... I think.   Basically, you harvest really early, cut the pod 
into little discs and lay the  discs in a petrie dish with 'nutrient agar'.  
From there I'm a bit  cloudy.  It seems like you would still have to proceed 
with your cold  stratification.  In my refrigerator healthy seeds get all 
moldy- and  nutrient agar is intended to grow molds for kids science projects- so 
how, I  wonder, would I keep from just growing molds?  There must be something 
I  missed.  All the websites I looked at were either someone's doctoral  
thesis, or for the fourth grade science fair.

i think  I may put in a call to the county extension office....

christian
ky

Response from Dennis Hager, Society For Japanese Irises
 
 
Christian, 
Embryo and endosperm  development are part of an interdependent reproductive 
process. For  fertilization to occur, the pollen grain must fertilize the egg  
to form the embryo AND the endosperm. This is botany 101, but most of  us 
never took it or didn't get it.  
As for embryo culture,  it is a sterile process. It has been written up in 
the AIS Bulletin at least 3  times, dating back to the early 1940's. Randolph 
wrote the  article. For over a decade, it was one of the most cited articles 
published  in the Bulletin.  
If you would like to  try embryo culture, I would recommend that you take a 
course in plant tissue  culture--or at least read a few books. Most 
universities and many community  colleges offer courses. If you insist on educating 
yourself through the  internet, there is a yahoo group for home tissue culture. 
However, it is a  marketing tool for the owner to promote weekend seminars on 
home tissue  culture. 
Embryo culture skips  the dormancy phase of germination, so there is no need 
to stratify seed. In  fact, fresh seed are easier to process. If you are going 
to attempt  embryo RESCUE (when there is no endosperm), then you have to 
harvest the  embryo and process it before it dies.  
Dennis  Hager 
_hager@aredee.com_ (h*@aredee.com)  
Also- On AIS Region 19  website, there is an AIS Bulletin Index database, 
where you can search for old  articles 
_http://www.jerseyiris.org/ais-index.htm_ 
(http://www.jerseyiris.org/ais-index.htm)   


Rita  Gormley
Gormley Greenery
Cedar Hill,  MO
http://www.gormleygreenery.com/

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