Crinum self-fertility

James Yourch
Fri, 11 Jun 2004 06:47:39 PDT
Jim McKenney wrote:

>How does one distinguish between apomixis and self-compatibility? The 
>concepts are clear enough, I think: apomixis is seed production without 
>fertilization -presumably involving unreduced gametes which preserve 
>the diploid ploidy level for basically diploid species;  
>self-compatibility on the other hand is the ability of a clone to 
>produce pollen which fertilizes the ovules of the same clone.

>Do we agree on the basics, or have I got the basics wrong?

>In either case, aren't the resulting "progeny" simply clones of the 
>parent? The resulting "seeds" are not really seeds, they are just 
>neatly packaged bits of the original plant. In the case of apomixis, 
>the tissue is all derived from the maternal line. In the case of 
>self-compatibility, the tissue is derived from both the maternal and 
>paternal lines, so-to-speak. Except that since the maternal and 
>paternal lines are the same clone, there is no significant difference.

I was hoping someone with a biology background would step forward to answer
this, but not yet.  So here is the Software Engineer's answer.

In the case of apomixis, they are seeds, they just happen to contain the
identical DNA as the mother plant, a clone.

In the self-compatible case, they are not clones of the mother plant because
there is still a mixing of genetic material during gamete formation and
fertilization.  I think that every gamete produced
by an individual is unique and therefore every seed produced would also be
unique, even if the mother and father of it is the same individual.
Remember Monty Python's "Every sperm is significant"?

With regards to your Hymenocallis seed question, they look just like Crinum
seeds.  Crinum mostly produce one to a few seeds per flower, but the seeds
are very large.  C. bulbispermum, maybe others too, can produce many seeds
per flower and the seeds are still large.    

Hope this helps,

Jay Yourch

Central North Carolina, USA (USDA Zone 7) 

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