We seem to be having trouble getting past defining or even using pure. The suggestion has been made to use a generational count the same as we use for mischling ie F1 equals first generation you have bred or can confirm true crossing of both parents from the same genetic line and then work up from there. F1 is unstable by F4 should be mostly stable with maybe the odd unusual outcome less than 1% and F5-10 totally true breeding all offspring are the same genetic variant as the parents. so lets see what everyone thinks of this direction give a yes or no response.

Below is the interesting responses.

1. Sorry, but does that mean juvies from a BB line that breeds 100% true and juvies from TBMM x TBMM would both be called F1 BB? If so, No. I don't think thats going to help anyone, especially beginners. Sorry if I have interpreted your definition incorrectly.

2. What if we categorise pure into 2 categories, for those that breed 99% true for the past 2 generations at least, call it Pure. 
And those that produce high % offspring of one variant (such as: MKK x MKK = 70% true MKK, rest tb,pinto,etc...), we call it line breed (selectively), which means you are selectively breeding one variant to increase % offspring of that variant. And it is necessary to included what are the offsprings from the batch, F number is recommended to included if the breeder is confident with their track record.

3. the word pure needs to be dropped, as no one can guarantee 100% that they will never produce anything other than the shrimp that looks like the parents and grandparents. I like the notion of F numbers however Mischling origin stock should be clearly labeled versus Cleanly bred stock(does not have Mischling decendants) that are currently breeding true.
 

I'm in agreement with both 2 and 3. "Pure" to me implies that the parents are one type of shrimp (be it a variant or species) and produce 100% (or close to) offspring that are the same.

Anything descended from a recent mischling or other hybrid cross cannot be 'pure' because it will always contain genes from that hybrid cross. I like the idea of using "pure" to define old school, defined variants (such as CRS or CBS, or tiger) that have not been crossed with any other variants, and using "line bred" to define variants with a hybrid ancestory that produce 100% (or very close to i.e. >95%) young that are the same variant as they are.

In the end you have to decide what the purpose is when you label something as "pure". Is the purpose to demonstrate that whoever buys your shrimp should end up with 100% offspring that are the same variant as their parents, or is the purpose to let the buyer know that the colony has been bred as a particular variant and not crossed with other variants?

I think "line bred" and the use of F numbers covers the first purpose, whereas "pure" is much more suited to the second.  

 

I think "line bred" and the use of F numbers covers the first purpose, whereas "pure" is much more suited to the second.  

I think fishmosy has summed up my thoughts on this.

I prefer option 3: rather than reading the word 'pure' and taking it as any definition, I'd much rather hear a description of the lineage (e.g. "I've never had mischlings in the same tank" or "You might get a few stripes due to a low percentage of tibee/tiger genes").

Ah, I guess that means I'm mostly agreeing with @fishmosy too :)

Yeah its tough to get everyone agreeing on one answer but I like where this discussion is going.

At the end of the day We want the seller to provide as much information to the buyer as possible to the genetics for the shrimps being sold. So the buyer can make a informed decision whether to add those shrimps to his/her colony. Recently there have been too many story where a hobbyist project has been ruined due to the buyer and seller having different definitions to the word pure.

We just want to pick the most suitable way of defining this so at least our members will be on the same page.