Inbreeding Depression

[Indica Jones]

Okay now I know this can occur with crossing siblings on down the line, but what about going past the cubing process? Past the third cross back to the mother.

[Marvin Martian]

Backcrosses and IBL's can sometimes be a bit less vigorous. Personally, I attribute that to inbreeding depression.

One of the first things I learned is there are no hard and fast rules, though. There are exceptions to any rule.....sometimes many. With that being said, in general, IBL's and backcrosses (earlier generations of the IBL) will not display the vigor of a good F-1. This is why some breeder's strategy for specific projects is to inbreed for stability for several generations, then outcross with dissimilar, also inbred lines. I am not sure if that answers your question, but at least it adds to the discussion. ;)

[suzy cremecheese]

The backcross/cube is commonly used, at least in tree fruit, to add one specific trait to a variety that is otherwise desirable. For instance to change the skin color of an apple.

One way that this can be done without the risk of inbreeding depression is to use unrelated varieties at every cross. Say you want to take a great yellow apple and make the skin red and keep everything else the same. You just use a different variety of red apple to contribute the red color to every generation. Every generation select progeny that are most like the orignal yellow apple witht he exception of skin color. Do it 4 or 5 times. Now your recurrent parent is no longer recurrent. You should be able to get alot further without problems.

Another problem is when people use the backcross to try and recreate a clone only in seed form. While this can certainly be done, if your going to run into inbreeding depression it is going to happen with a cubing procedure that has the same recurrent parent every generation and your selection criteria is for plants that most resemble the recurrent parent.

Unfortunatly there isnt a reliable cannabis genome bank with a list of traits that each variety passes on fairly reliably. Maybe one day.

[Genghis Bong]

Okay now I know this can occur with crossing siblings on down the line, but what about going past the cubing process? Past the third cross back to the mother.

I remember Mr. Soul saying that he ran into problems when going past the cubing. Can't remember what he said specifically as to what problems arose but for sure he didn't like the results.

[Cuzin_Dave]

Inbreeding depression is almost always assumed to be a natural occurrence in cannabis even if the evidence is not there, nor the standards of measurement. For the same reason it is assumed in the world of cannabis breeding (such as it is these days) that something called an F1 hybrid will always yield superior results. Old shibboleths die hard in the cannabis community about what constitutes good breeding practises. The proof, in my estimation would be whether or not a given overall population of plants was showing an overall decline in relative fitness on a population curve.