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Question about F1 hybrids
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Posted by Raymondo NSW Aust (My Page) on Sat, Feb 28, 04 at 6:59
| Is it the case that for ALL plants, the F1s from a cross are genetically identical? I can understand that this might be so for a stable line of an inbreeder but I'm trying to get my head round it for an outbreeder, especially one that shows marked inbreeding depression like corn. Sorry, I'm a novice here and am just trying to get an understanding of it. |
Follow-Up Postings:
RE: Question about F1 hybrids
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Raymondo,
Here is my understanding of the generalities. If both of the parents are relatively uniform (when grown from seed for instance), the F1 between them should also be relatively uniform. If either or both of the parents is not true-breeding (shows a lot of variation when grown from seed), then the F1 should also show quite a bit a variation. So, the very uniform F1 commercial seed (you see sold in catalogs, etc.) comes from crosses of very uniform inbred parent strains. Even in outbreeding plants, for example corn, breeders have developed relatively uniform inbreds to combine for hybrid seed production.
Actually corn is probably a bad example to use -- since much of the hybrid corn seed is the product of crossing two F1 hybrids (each a product of two uniform inbreds). This F2 may not be as uniform as an F1, but is still uniform enough for crop production.
Hope this is helpful in answering your question. Tom |
RE: Question about F1 hybrids
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Corn went through a stage when comercial hybrid corn was, as said by Tom, hybrids between two F1 hybrids. This was because inbreds were so week that they didn't produce much seed or pollen. they were just plain hard to grow.
But then better inbreds were developed, and most are now single cross hybrids. Especially sweet sorn is mostly grown from single cross hybrids. The uniformity is valued enough that the more expensive single cross, true F1 seed is generally used now. |
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