Re: 935 LLoyd seeds
- To: pumpkins@mallorn.com
- Subject: Re: 935 LLoyd seeds
- From: H* E* P*
- Date: Sun, 25 Apr 1999 13:50:45 -0700
- References:
pumpkins@mallorn.com wrote:
>
>
> I have about 200 of the 935 seeds.
> Here's why.
> I self pollinate the 935, so there are no other genetics,I harvested
> more ,seeds but gave a lot away.
> I was at the pumpkin seminar in Guelph, and spoke to George, he said
> this should be the last set of seeds, for self pollination (4
> yrs)when they are planted this year, they must be crossed pollinated
> with another pumpkin.
Have I understood your letter? Are you saying "I selfed 935 for 4
years and therefore it is still just like the original 935?
I agree that if you covered the male and female flowers and selfed
then all the genes in your 4th generation came from 935 Lloyd. However,
you have lost lots of the genes in that original. There is no way to
avoid that via annual seeds.
Lets look at that first year and only one chomosome pair. Lets call
them 1M and 1F (#1 from sire, #1 from Dam). Draw your Punnett square and
you find 1/2 of the offspring of a self got 1M and 1F (we will ignore
crossing over, but crossing over is an important factor!!). Thus, 1/2 of
the progeny got the same chromosmes as in the original seed from 935.
But there are 12 sets of chromosomes ( I am not sure about that for
AG) so 1/2 to the 12th power is 0.0002. So 0.02% of the seeds got the
same genome that you planted. (That seems high, maybe I am using this
calculator wrong.)
If you have selfed 4 years, I am not sure how to calculate, but I
think it is .0002 to the fourth power.
Also keep in mind that the seed you got out of the 935 Lloyd had very
little genome in common with the seed Lloyd planted.
Genetics can be very discouraging. However, it is this profusion of
possibilities which enables rapid progress in plant breeding.
The preceeding numbers show why it is so easy to lose disease
resistance which was common in the wild ancestors of our crops.
--
Harold Eddleman Ph.D. Microbiologist. i*@disknet.com
Location: Palmyra IN USA; 36 kilometers west of Louisville, Kentucky
http://www.disknet.com/indiana_biolab
---------------------------------------------------------------------
To sign-off this list, send email to majordomo@mallorn.com with the
message text UNSUBSCRIBE PUMPKINS
