Sign in to follow this  
ewjlamb

Simple Hybrids and Mendel's Laws

Recommended Posts

Hi all!

 

I have a question.

A little while ago I sent away for some Sarracenia seed which was advertised as Sarracenia x Catesbyi X Catesbyi.

This was obtained from a reputable source and it proved viable. I now have a small pot with many seedlings. Yeeeay! :-)

 

I do not know whether this seed was produced by cross-pollinating two separate plants, both the above hybrid; or whether instead, it was from a 'self' on a single specimen of Sarracenia xCatesbyi.

 

But I am interested to know what my young plants may turn out to be....

My question is, "If you make a simple hybrid, such as Sarracenia purpurea x Sarracenia flava and take the progeny, i.e. Sarracenia x Catesbyi then cross the progeny with a similarly-conceived simple hybrid of like specific parentage, then do you get a mixture of the parent species and the hybrid S. Catesbyi in third generation plants? (Or are all the third generation plants hybrids, in fact?)"

 

To those who claim that I should be answering this question for myself, I might add here, that it appears at this stage that all the seedlings in my pot show little variation and therefore no reversion occurs in this case.... which makes me wonder why it happens within a species for flower-colour n sweet peas.

 

The other question is, what is the difference between Sarracenia xCatesbyi, and S. Catesbyi X Catesbyi; in other words, what extra information is the originator of this seed conveying in terms of genotype or other properties?

 

With thanks for your attention. I am quite a newbie in growing Sarras from seed, but it is a uniquely satisfying pursuit to me.

 

Jon

Edited by ewjlamb

Share this post


Link to post
Share on other sites

Jon,

sarracenia catesbaei or s.flava x s.purpurea will usually be somwhere in the middle of each parent looks wise on the first simple cross.

If you cross two s.catesbaei or self one plant,i would expect to get a variation in the seedlings.

Some would look more flava like,most would be like s.catesbaei and some would be more purpurea looking but all would be hybrids,no reverting back to species once they are crossed.

That is in simple terms,but this can be affected by other factors.The seed parent usually influences looks on the seedlings more than the pollen parent and some plants have a much larger influence when passing on colour or shape.

I think the supplier of your seed was saying that he crossed two different s.catesbaei plants,i would have put s.catesbaei "selfed" if i had only used one plant.

hope this helps a bit.

ada

Share this post


Link to post
Share on other sites

I think the general rule would be that a third would look like an intermediate mix of flava and purpurea, a third would lean more towards purpurea and a third would lean more towards flava.

Share this post


Link to post
Share on other sites

OK thanks for your answers.

Getting the hang of this stuff is quite tricky to be sure.

 

In terms of labelling my seedlings, though, I geuess the thing to do, is wait till they are developed with 'proper' characeterisitcs and see if any merit a 'type' label as S. x Catesbaei, but not to label any as S. flava or S. purp., because they are not.

 

The Holland vs Costa Rica match was gripping.

 

Cheers!

Share this post


Link to post
Share on other sites

Guys, it is just S. x catesbaei F2.

 

Or S. x catesbaei.

Share this post


Link to post
Share on other sites

By Mendel's Law 25% will be like S. flava, 25% like S. purpurea and 50% intermediate. I think if you start counting with a reasonable sample size you'll find the numbers add up. Ah! the fun to be had with fruit flies to check out Mendelian genetics.  :good2:

Share this post


Link to post
Share on other sites

Sorry, reading this: "That is in simple terms,but this can be affected by other factors.The seed parent usually influences looks on the seedlings more than the pollen parent and some plants have a much larger influence when passing on colour or shape."

 

- Did about 600 crossings, about 150 of them vice-versa and never noticed that :-(

Share this post


Link to post
Share on other sites

If you have enough genes influencing the look of the plant, you will get an alpha (ie bell shaped) dstribution of plants ranging from extremely rarely a pure species (think lottery chances) to 50/50 split any every possible combnation inbetween. Roughly speaking that works out to be most of the plants looking a bit like the hybrid parents and the number rapidly falling of as they start to look more like either of the original species.

If one parent dominates it skews the distribution in that direction but the spread will still cover the entire range of possibilities. (given enough progeny).

Edited by manders
  • Like 1

Share this post


Link to post
Share on other sites

Mendel's law applies only to monogenic inheritance. This simply means that a trait is defined by one single gene. Not all genes are inherited in such a fashion, and are more commonly inherited polygenically, which means more than one genes interact together. It might be that inheritance in the Nepenthes genus is inherited in such a way - creating a normal distribution curve as manders explains above.

Sent from my iPhone using Tapatalk

  • Like 2

Share this post


Link to post
Share on other sites

Epistasis is probably also an important factor.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this