The selection of the line you choose to start your breeding program may or may not have many choices. The color, style, temperament and other considerations: movement, longevity, hips and other health issues could force you to narrow the choice to the point that you only have one line to make a selection in all the breed's kennels in the world.
But, this may also be a great illusion, as all of the dogs within a particular color, style (sometimes called type) and structure (phenotype) are really derived from one or two actual true genetic bloodlines. The difference between a bloodline and kennel line can be a fine line or a very broad one; much depends on whether you accept the genetic definition or prefer the more popular common definition of bloodline.
Genetic definition: Bloodline - the production of genetically fixed specimens of a limited select breeding population. So phenotypical that all animals (from a genetic standpoint) exhibit distinquishable traits from the general population and will continue to produce true to these distinct traits due to the "homogonization" of genetic material. The product of many generations of brother/sister, father/daughter, mother/son, uncle/neice and aunt/nephew breeding stablizes the genetic material. In general only F1 (first generation) mutations will produce distinct genetic diversity; otherwise, the mutation is possibly common amongst the whole selected population.
Strain - is defined as a population that when bred together will have few, if any genetically distinct differences except sex (and possibly color/markings if in a multi-colored population). This category is even more intensely inbred than a true bloodline. Genetically, individuals within a strain will be seen as twins, and after many generations of isolated breeding, littermates of the same sex would be considered genetic identical twins.
More common definition: Bloodline - direct line of descent, a pedigree of some common ancestry. This would more fit my definition of a kennel line.
In the past, most purebred dogs were so closely bred that they produced true to type/style when bred together. The local populations became almost a genetic strain due to the fact that each individual, when bred to another produced a type/style that was unmistakably a member of the breed: Great Dane, Dobermann, German Shepherd, etc and identifiably distinct within that location and were very tightly inbred.
The crossing of populations from various local areas, would also produce the same type because each population was from the same "breeding strain" or bloodline of less close inbreeding. Therefore, each local population was just a specialized subset of the breed and still within the same strain.
As inbreeding continued, specific mutations became identified within specific local populations. Also, by cross breeding populations and inbreeding the results, more mutations were collectively contributing variation to the gene pool within the overal breeding population. These mutations would be concentrated within specific local populations by closed line breeding or inbreeding to the point that all individuals of the local population carried the mutation and could be identified as a member of that local population on sight (a distinct bloodline).
After a century or more of such breeding, and mixing of local populations, we have the variations we now see in our dogs, even within the same breed. Some kennels have further inbred their dogs to the point that individuals of that kennel exhibit the same mutations and are homozygous for it within their kennel sub-population or bloddline. They also may all carry recessive mutations that are prominent amoung the sub-population such a color (gray) or head type (wide base), height (longer legs), tail carriage (saber curve), etc. The variation of genetic material of each sub-population or bloodline is truly what we are selecting when breeding. Making the choice to use or not use individuals and specific traits in the selection of our breeding lines.
Each line (kennel line, bloodline,local population or sub-strain) has hidden traits that we need to be aware of in our selection of breeding stock. This applies both to the females we purchase and the males we us to produce her offspring. Therefore, the more we know of the recessives of each line we use, the more control we can execute in the production of future breeding stock in our lines.
As breeders, we should strive to develop this knowledge and share it with other breeders. The breeding population is now a global marketplace affair and as we spread genetic material across the globe, we are diversifying gene pools and introducing new traits into the local populations. These introductions need to be documented and records maintained to enlighten other breeders of the impact seen in each individual breeding experiment. Documentation must also be maintained on the impact seen with various new sub-populations being developed as a product of these experiments.
If we fail to document and dissiminate this information, we have no chance of maintaining the breed as we have come to know them. Each local population runs the risk of diversifying into a new distinct variety in the breed or a new breed of dog all together.
Maintaining a sub-population that closely fits the current Breed Standard is important if we wish to have any success in producing champion stock in our kennels. If you are not interested in producing champion stock or dogs that meet the standard - please leave the breed and produce mongrols. To define/standardize these traits, having all dogs of our stock exhibit them and make them dominate in our stock should be the goal of any and every breeder. In most cases this would require developing a breed "type/style" in our minds that can be maintained in our stock that best fits the Standard of our breed. These should produce true to type, generation after generation and exhibit little change over time due to undesired or unknown recessive traits or mutations.
That scheme is what the breeders of the original foundation stock of all breeds accomplished in developing the breeds we have today.
This dedication to producing stock that holds true to type is what is needed if we are to begin or continue to improve our breeding stock.
Ruthless examination and evaluation of the breeding stock will be required to cull from the breeding population (within your kennel and local area) all dogs that show deviation from your pre-determined definition of type and style within your kennel.
This my (to some) fit the definition of "type" breeding; but, without the continuation of inbreeding and tight line breeding, you run the risk of also introducing new genes that you have not planned into the genepool. Therefore, both type breeding within inbreeding and line breeding plays an important role in the selection of stock you use in your breeding experiments.
The development of a breeding plan, to be used for several generations into the future, based on the current stock you have available (and the planned offspring), utilizing the selection criteria for show traits (breeding to the standard) - this is the begining of creating a breeding program that could lead to the breeding of a champion dynastic line.
In the following chapters and subsections we will examine the products of many kennels that have produced such dynasties. We will look at the lines used, those developed and the impact they had on future lines. We will examine the choices made in each breeding based on what occurred. We will not be speculating on the reasoning for those choices (as we have no access to the thought processes or plans of the breeders in the past); but, rather by examination of the offspring produced, based on traits we see (phenotype) passed from generation to generation, observing the physical outcome of these breeding experiments develop our own rationale for such pairings.
We will examine pedigrees and photographs of dogs in the pedigrees to develop theories we can apply to our own breeding experiments and work into our own plans for future breeding programs. We undergo this process in hopes of developing a breeding program that will eventually lead to our own dynasty of champions.
This will be no quick trip to the nearest breeder, put a pair together and hope for the best; but, rather we prepare ourselves for a voyage that will end in a life long journey of breeding. The true success of this experiment will not be seen in our lifetime (though some measure my be found in a few generations of show win success); but, will only be seen by generations of breeding in the future.