Crossing seperate lines of the same strain

As many of you will know, IBLs tend to loose vigor the more they are inbred. It's a sacrifice breeders have to make in order to stabilize a strain, or at least that seems to be the general perception. Many strains of yesteryear that have been preserved and kept pure suffer from slow growth and lack of vigor in general, which is frustrating for growers and breeders alike. Prime examples would be things like Tom Hill's Deep Chunk and Original Haze.

In the past I have heard of breeders claiming to get around this problem by working two separate lines of the same strain in parallel for a number of generations, till all the traits they want are well and truly fixed in both lines, and then combining the lines as a last step. Since the two lines have effectively diverged to form distinctly separate gene pools, combining them restores vigor whilst at the same time maintaining the purity of the strain, or so the theory goes.

Something like this (hope it comes out ok):

P1:..............................strain 1 x strain 2
.......................................= strain 3

F1:..............strain 3 x strain 3........ strain 3 x strain 3
..........................(line 1)......................(line 2)

F2:..............strain 3 x strain 3........ strain 3 x strain 3
..........................(line 1)......................(line 2)

F3:..............strain 3 x strain 3........ strain 3 x strain 3
..........................(line 1)......................(line 2)

F4:.....................strain 3(line 1) x strain 3(line 2)
..................................... = strain 3 IBL


It seems to me that there are quite a few strains which have already had most of this work done for us, and just require the final step, to combine and restore vigor to the line.

For example, I have Herijuana from Reeferman, Motarebel and 3LB. They are all pure, but at the same time have been further inbred as separate lines. One day if/when I have the space I hope to run all three lines, selecting the best individuals from each and eventually combine them to produce a hopefully vigorous and uniform single line. I know it will be quite allot of work, but should be worth it.

What surprises me, is that I can't recall ever seeing this technique mentioned here on CW, when it seems to be just what many of us are looking for.

I'd be interested to hear if anybody here has come across or has any experience of this technique, and also if you have any thoughts as to it's potential for restoring vigor to old and tired lines, as well as its use in breeding a new IBL from scratch.

Cheers!
ng

PS. Tried to post this in breeders lab, but could not! Hope it's ok here!

No one has an opinion on this?????

Funny, I just posted in the other thread wondering if Deep Chunk had this problem! LOL

Neon - will give a thorough read.

like say strainwhore, look here i have made a breeding plan for you : http://www.icmag.com/ic/showthread.php?t=92423

Howdy

Howdy

Great thread!

Yes in theory I agree with what you are saying and writing.

This should work.

Something else I am aware of was done as you wrote. This was a melon that used to grow wild in JAPAN.
But has been very inbred.

An open pollenation from a close but wild plant was done. Then essentially your model was used to try to "re-create" the old melon..


Now on our subject..I myself will have to do similar things for My BOG Preservation Project.

In order to not lose BOGs vigor I am going to have to use lines that are as seperate phenotypically to develop the line 1 and line 2 and recombine later for a [hopefully ]still vigorous line/strain 3.

This should keep the "IBL" and most importyant the hybrid vigor.

Of course it can probably never have the vigor of lets say, a seperate C.Indica line and a seperate C.Sativa line.


thanks
sw

Thanks for all your comments, and giving this thread a second chance at life.

I was perhaps under the impression when I started this thread, that this technique could restore lost vigor from a strain, but I now think that was over-optimistic.

However, I do think it has the potential to minimize the loss of vigor over the course of a breeding project, weather it be from scratch, or as a continuation of someone else's work to preserve a strain (eg. Deep Chunk, Heri, etc).

I don't think there is a way to restore already lost vigor (which Chimera confirmed in the other thread), but it seems to me that it's the obvious path to follow if you want to create the most vigorous IBL you can without sacrificing the consistency of the progeny.

Of course, if vigor is all you are interested in, and you have the space/inclination to grow out 1000s of plants for each generation, then perhaps an open pollination and culling any undesirable individuals might be even better. We all know how large landrace populations have been kept going over countless generations without any loss in vigor, but obviously this is not always possible, and the technique we are discussing could be used as an alternative to achieve "similar" results.

What surprises me, is that I can't recall ever seeing this technique mentioned here on CW, when it seems to be just what many of us are looking for

Click to expand...

i read your reply on another thread on ibls and you linked to this saying you had no replys,just thought i'd show you why maybe that is....this is icmag,not cw.
thanks for the info though,i am only messing and hope it don't upset as that wasn't my intention.
bests

LOL good point potty1.

Little slip there. Perhaps even wishful thinking... I meant to say icmag of course.