Re: HYB: trying to learn some genetics terminology
iris@hort.net
  • Subject: Re: HYB: trying to learn some genetics terminology
  • From: C* C* <i*@aim.com>
  • Date: Fri, 22 Feb 2013 12:12:04 -0500 (EST)
Be careful in reading the page you posted. It is about populations, population drift, and inbreeding depression in natural species, in isolated patches. Not about hybridizing. So the inbreeding they are referring to is population inbreeding, unless they specifically say it is on same plant. So the inbreeding would be of two related plants, not necessarily of pollen from same individual plant on pod from same individual plant.
The study of isolated populations makes for interesting evolution and genetic population studies, so of interest to scientists. But not much information for backyard hybridizers. At lest not much, if anything you can use. 

Chuck Chapman

-----Original Message-----
From: Linda Mann <lmann@lock-net.com>
To: iris <iris@hort.net>
Sent: Fri, Feb 22, 2013 10:37 am
Subject: Re: [iris] HYB: trying to learn some genetics terminology

Thanks Tom.

I found something online that says:
Inbreeding of course can also occur in plants through the mating
between close relatives, which is termed biparental inbreeding to differentiate it from selfing (Griffin and Eckert 2003) 

From:
<http://www.as.wvu.edu/~kgarbutt/QuantGen/Gen535_2_2004/Inbreeding_Plants
.htm>

This is an article about inbreeding in natural plant populations, no
idea if 'biparental inbreeding' is a term used in horticultural genetics. 

It also includes this:
<Furthermore, many plants have multiple flowers or inflorescences per
individual, allowing for another type of self-fertilization, termed
geitonogamy (Jain 1976). Darwin (1876) showed in early studies that this 
type of selfing differs from selfing within flowers in terms of the
quality of offspring produced.>

What the?? as if the subject weren't already confusing enough - why
would one flower crossing with another flower on the same plant produce
'better' offspring than selfing the same flower? I don't think I really 
want to know.....

IMMORTALITY routinely produces few seeds per pod, has poor germination.
Robin Shadlow sent me a huge number of seeds from an IMMORTALITY cross 
she made for me - not sure if they were from Nebraska or OR, & I've
gotten a normal number of seeds in a pod now and then.  So I'd always
assumed the low seed set and low germination rate were mostly due to my
wretched growing conditions, not inbreeding depression.  Is there an
easy way to guess which it is? Or should I assume it's some of both?

I wonder if I'm going to remember any of this come breeding season....

Linda Mann

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