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Carol_A:
What are "segregating hybrids"?  I keep coming across this term.

joseph:

If plants of two different varieties or species are crossed that makes a hybrid. If we use consistent parents to make the hybrid, then the children are consistent. The first hybrid generation are called "F1 hybrids".

If the seeds of a hybrid are saved and replanted, then things can get really interesting: Because the genes are sorting themselves out into lots of new combinations. We call that rearrangement of the genes "segregation". The rearrangement occurs most noticeably in the grandchildren of the cross, often called the "F2". But it continues in varying degrees through about the 5th generation.

Here is an example with dry beans:

The mother of an F1 hybrid looked like this:

Mother of cross. Bush bean.


Hybrid beans: F1. Father of the cross unknown. Probably speckled. Probably dark colored. Definitely a pole bean.


Segregating hybrid: F2. Grandchildren of the cross. About 1/4 bush beans, and 3/4 pole beans. Saved seed only from bush beans.


Segregating hybrid: F3. Great grandchildren of the cross. Only bush beans.


Rather than growing these as a mixed population, I could pull individual colors out to grow as a pure variety.

Carol_A:
So you're not adding new genetic material to the mix, instead just selecting, and letting new combinations develop. 

joseph:

--- Quote from: Carol_A on 2016-February-07 01:27:39 PM ---So you're not adding new genetic material to the mix, instead just selecting, and letting new combinations develop.
--- End quote ---

Correct for "segregating hybrids". 

Segregating hybrids in which all of the offspring are descended from the same parent are also called clades. All the seeds in the population are cousins or siblings.

My dry bush beans in the 2015 growing season included 3 clades. During the 2016 growing season, I am intending to grow 6 or 7 clades.

I grow the clades separately. Then I add seed from the clades to the general population. I also add new varieties to the general population as I trial new varieties and find some that work well here.

When I find new hybrids, I grow them separately for a year or two, while I select out of them the types that work for me, then I add them back into the general population.

Carol_A:
Are all the seeds produced from a given plant identical genetically?

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