Back Crosses Numbering What do the 0.5s mean

[madcat]

How does the numbering for back crosses work? Does each succeeding back cross add 0.5 i.e. a BX 1.5 would be the 3rd back cross?

Is back crossing an acceptable means of acheiving stabilization. By the sixth BX you should be at 99.6% of your desired genetics. Not as fast as selfing but better results?

 

[Guest]

How does the numbering for back crosses work? Does each succeeding back cross add 0.5 i.e. a BX 1.5 would be the 3rd back cross?

Is back crossing an acceptable means of acheiving stabilization. By the sixth BX you should be at 99.6% of your desired genetics. Not as fast as selfing but better results?

madcat,

im thinkin that 1.5 sounds better than 1.0, lol.

1.5 the first BX, 2.5 second and so on. 3 BXs and youve done a cube, which with proper selection you shoulds have a pretty tight group of plants.

6 Bxs wow id think that would be just about it, lol.

I think a certain # of BXs would produce a much better population than a single self.

just what im thinkin but have been wrong. maybe Rez or Bog will chime in on the BXs.

CBF

 

[Gamma Goblin]

The usual way to number it is:
First back-cross BX1
Second back-cross BX2
etc.

Rezdog added the extra 0.5 because the father (NYCD) already had diesel in it, so:

DSD = NYCDxECSD
Sour Diesel BX 1.5 = DSDxECSD
Sour Diesel BX 2.5 = SDBX1.5xECSD

If one back-crossed to a mother six times the result would be inbred, poor-quality plants. Back-crossing just a few times to avoid loss of potency and vigour would still not guarantee stable plants. Recessive genes could assert themselves at each back-cross. However success is possible in cubing plants; Cinderella 99 and Rezdog's SD BX 2.5 have met with much favour.

Using both back-crossing for stability and sibling-inbreeding would give better results. DJ Short made Blueberry this way and Rezdog is also using incrossing in his Sour Diesel project.

 

[Capt. Crip]

thought

thought

Inbreed in the population to stabilize,and do backcrosses to reinforce parental traits or to restore vigor.

 

[Guest]

thank you capt

CBF

 

[madcat]

So at what BX is should you start breeding within the population

So at what BX is should you start breeding within the population

Thanks for the input,

I was just going to use multiple males (4 to 6) in the BXs selecting them by vigor, node spacing, and smell to maintian diversity and avoid unwanted recessives. Its sounding like I should go to a cube - breed within the population - and then go to mom again?

 

[Gamma Goblin]

Using both back-crossing for stability and sibling-inbreeding...

Oops. Should have been:

"Using both back-crossing and sibling-inbreeding for stability..."

The recessive genes in the mother plant will be donated to offspring every time you back-cross. These will need to be bred out afterwards if you want a stable strain.

If you cube a true-breeding plant then you will have great success. If it is an F1 you will tear your hair out. I suggest you read a book about genetics and breeding. "Marijuana Botany" by Clarke is posted somewhere on this site. I think DJ Short's book is too.

 

[Guest]

GG: The usual way to number it is:
First back-cross-BX1,Second back-cross-BX2,etc.
(However,in the Sour Diesel Project) Rezdog added the extra 0.5 because the father (NYCD) already had diesel in it.

Rez: Thanks,GG,that's exactly right.
If you don't mind,I'll jump in here for a minute and add a few things :smile:
Here's the genetic lineup of the Sour Diesel Projects:
ECSD X NYCD = DSD
ECSD/NYCD X ECSD/NYCD = DSDv2 (f2)
ECSD X DSD = Sour Diesel BX 1.5
ECSD X SD BX 1.5 = Sour Diesel BX 2.5
1st Sibling Incross = Petrol
2nd Sibling Incross = Sour Diesel (Coming Soon!)
(Oh,and several Sour Desel hybrids,as well!)
As you can see,tis' not a small effort,and it's been no easy,simple, or cheap (lol!) task.....

GG: If one back-crossed to a mother six times the result would be inbred, poor-quality plants.

Rez: Yup,one or two BX's will do. Imho.

GG: Back-crossing just a few times to avoid loss of potency and vigour would still not guarantee stable plants.

Rez: It's ALL about a balanced program,and selection.
We select,select,select....

GG: Recessive genes could assert themselves at each back-cross.

Rez: True,that's why selection,re-selection,and research,are so important when you're trying to achieve something like this outside of a laboratory environment. Knowing your parent stock is imperative,and not being afraid to throw plants out that don't vibe you right is also very important (insert NewAge joke here!)

GG: However success is possible in cubing plants;Cinderella 99 and Rezdog's SD BX 2.5 have met with much favour.

Rez: 'Cubing' suggests three backcrosses,and I'd advocate only one,or two,at best....mixing BX'ing and sib incrossing is the way to go....imHo.
It's been a long selection process,and quite a few cycles,but we feel we have a Big Winner-a stablised Sour Diesel seedline....almost finished.

GG: Using both back-crossing for stability and sibling-inbreeding would give better results.
DJ Short made Blueberry this way and Rezdog is also using incrossing in his Sour Diesel project.

Rez: We're doing our second Sour Diesel sibling incross as we speak,and we expect,from all we've learned,that this one will be The One:as ECSD Clone-dom as you're ever gonna' get from seed,with the same taste and high,but with a MUCH better yield,and less prone to stressing than the ECSD Clone Mom is.To me,that's improving an already fantastic smoke,and I'm very happy with the results.
This one's gonna' be huge.

 

[Guest]

Sour Diesel X Willem's Wonder = Sour Wonder...or.... Willem's Wiesel

Sorry Rez. Mastergrow->