Hybrid Question

[Andrew]

Something that I don't believe was mentioned was the effect of the parent's plastid (eg chloroplast) and mitochondrial DNA on the progeny (especially on size, vigour, etc). These genes are passed on through the pod parent.

[shakkai]

Originally Posted by Andrew

Something that I don't believe was mentioned was the effect of the parent's plastid (eg chloroplast) and mitochondrial DNA on the progeny (especially on size, vigour, etc). These genes are passed on through the pod parent.

Andrew, I did mention that certain traits in plants were only inherited from the pod parent. The example that I gave was variegation - I know that is true in certain plants, but I wasn't sure it was also true in orchids.

You are absolutely right, sometimes it makes a very big difference to resulting offspring which plant is used as the pod parent. Though, again, for orchids, it wouldn't change the actual name of the resulting hybrid.

Okay, another couple of questions.

Say you have my previously stated hybrid the den. 'Hawaii' from a den. phal X den. tokai. How likely is it that another hybrid from the same parents would be genetically the same as the original hybrid.

That would depend on the chromosome count involved, then you need to calculate out how many different combinations were possible. It's a lot like playing the lottery!!

And what if you got another Hawaii but from a different set of parents, would the genetic make up be the same as the first hybrid created?

No, they would be different genetically as the parent plants are different genetically. This is one of the reasons that named and awarded individuals of a grex are valuable, as they can be used to pass on those superior qualities in breedling.

[TheNewGuy]

OK, That make sense. And now for another question!!!!

What causes certain hybrids (Such as the Miltassia C.M. Fitch 'Izumi') to be sterile when used as a pod parent, and can you tell without actually trying to grow seeds?

[maitaman]

The results of reverse pollination will be basically the same. The plants may show different characteristics with a different "mother" plant as there are what is called "floating genes influence" from the mother plant. The complicated genetics of orchids gives huge variations even from the same seed capsule, but there is that influence from the pod plant.
The cross name is, of course, the same. C. aurantiaca X C. skinneri = C. Guatemalensis and C. skinneri X C. aurantiaca = C. Guatemalensis.

[Ray]

It is highly unlikely that any two plants of the same cross will have identical genes. It's fairly simple statistics:

Let's say the particular plants as 24 gene pairs. Each half of the A-B pair, as has been discussed above, can have a dominant or recessive gene, meaning that for a single pair, there are 4 possible combinations - AB, Ab, aB, and ab. That means that any single plant can have one out of 4 to the 24th power (281,474,976,710,656) possible combinations. That's a 0.00000000000036% chance that two would be identical, and when you consider that a large, fat capsule might have 200,000 seeds, the odds are very much against it.

[Bird Song Farm]

For those of you who remember "Welcome Back Cotter"................."I'm sooooo confused!"

Al

[cb977]

Does anybody else smell the brain cells burning up in here?

[orchids3]

I think its and enlightening chain and appreciate the inputs very much. Genetics and hybridizing is very complicated and thats why few really good hybrids are produced by amateurs. It is worthwhile to know as much about it as possible when I lay down my cash for an unbloomed seedling cross. Few hybridizers will sell you their best plant but you may very well get the best plant by making enlightened purchases of unbloomed seedlings.

[Tindomul]

Sterility can be caused by an abnormal number of chromosomes. Mules are sterile, because they are hybrids. Basically, the genes from the parent plants don't play nice with each other. Actually thats the best explanation I can give as I lack some knowledge here. Plants break this rule a lot (the rule that says hybrids between two different species will end up being sterile) apparently plants did not read the text book. In any case the greater the genetic differences are between parent plants, the greater the chance for offspring sterility.

[Daemos]

thank god we have meristem propagation these days or all those biauty hybrids go nowhere