Sharing seeds of rare plants/inbreeding depression

Ernie DeMarie via pbs
Fri, 14 Nov 2014 17:36:57 PST

Inbreeding depression is a problem with many species, but it can be avoided if seeds are banked early on in a fridge or freezer so more genotypes can be preserved if the inbreeding is so severe that it results in essentially homozygous weak plants.  Backcrossing to plants raised from stored seed with some different alleles should restore vigor.  Its also possible that if large enough populations are maintained some genetic diversity can also be maintained, I think the minimum ideal is something like 50 plants. Smaller populations maintained in different gardens over time also would be a way to avoid inbreeding if seed is exchanged between the gardeners every so often, since it is unlikely that the exact same alleles will be lost in each individual population.   It also seems that some plants maintain vigor over several generations in horticulture, they must have some way of avoiding inbreeding depression, or maybe harmful recessive alleles get selected out over time.  I know 
 I have been growing Impatiens namchabarwensis since it first got to the USA (via Plant World Seeds) and it is still vigorous and reseeds just fine.  
If wild populations of the plant still exist, then indeed periodic fresh introductions into the gene pool would avoid inbreeding issues. 
Ernie DeMarie
NY where we still have managed to avoid frost, but tonight will be the night as they forecast upper 20s.  
-----Original Message-----
From: BO MAGRYS <>
To: pbs <>
Sent: Fri, Nov 14, 2014 8:22 pm
Subject: [pbs] Sharing seeds of rare plants

It seems that Amorphophallus titanum specimens at various botanic 
gardens are blooming more frequently on younger plants and with smaller 
inflorescences. Are we selecting for this? It may be time to introduce 
new genes from the wild into our captive polulations. 

I've grown many choice self-seeding annuals starting from a single 
specimen for years (Impatiens namchabarwensis being one, another Solanum 
atropurpureum). Eventually inbreeding depression takes place and the 
plants have less vigor and succumb.



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