Thread: Heterosis
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Old July 14, 2017   #3
StrongPlant
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Join Date: Jun 2016
Location: Europe/Serbia-Belgrade
Posts: 151
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Quote:
Originally Posted by crmauch View Post
I remember reading a book about breeding that overall wasn't all that useful as it was mainly about breeding grains and mass selection.

However, the author stated something at one point, paraphrasing here (breeding inferior to inferior is almost never useful, superior to superior is obvious and beneficial, but some of the most surprising and beneficial results are breeding inferior to superior). He didn't explain why.

If I had to guess, I would say that the inferior has so many homozygous genes that are slightly harmful that the hybrid created eliminates all these suppressed homozygous impediments allowing the hybrid result to be drastically improved.
I am somewhat surprised that you've seen so much improvement. I'm under the strong impression that though tomatoes do suffer some inbreeding suppression, that it wasn't that significant (as compared to corn, etc).

the Wikipedia article about heterosis was good and talked about the ideas of dominance/ over-dominance and epigenetics.
In tomatoes it's definitely less dramatic then in corn,but...I've read that crosses of domestic tomato with some strains of S.pennellii were quite impressive in terms of vegetative frowth,i.e. biomass acumulation.

The cross I mentioned has such fast growth,that is now over 4m tall,while both parents are just reaching 2m.Planted at the same time of course.
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