# Inbreeding plants



## Outkast Seeds (Feb 6, 2008)

Inbreeding.....the Skill of the Breeder..... 
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INBREEDING:... is the breeding together of closely related plants or animals, for example mother/son, father/daughter and sibling/sibling crossings. For breeders, it is a useful way of fixing traits into a strain, breed or variety. 

Inbreeding does hold some potential problems.

The limited gene pool caused by continued inbreeding means that deleterious or harmful genes become widespread and the breed then loses its vigor. 

Laboratory animal suppliers depend on this to create very uniform strains of animals which are immuno-depressed or breed true for one particular disorder or another, for example: epilepsy for testing drugs for epilepsy..... 

Such animals are so inbred as to be genetically identical (virtually clones!), a situation normally only seen in identical twins. Similarly, a controlled amount of inbreeding can be used to fix desirable traits in farm livestock and plants, for example: milk yields and in cannabis, density of buds, buds to leaf ratios, rate of growth, color, flavor etc. 

Natural Occurrence of Inbreeding......

A wolf pack, which is totally isolated from other wolf packs, by geographical or other factors, can become very inbred.....Also so can be said of cannabis varieties isolated in remote locations up in the hills and valley's around the world that are inbred successively over many generations to create what is know as a 'Land-Race' variety or strain as say in the Parvati Valley in India with many varieties/strains named after their location of cultivation...(the village name)... 

.....LANDRACE: refers to a race of animals or plants ideally suited for the land (environment) in which they live and, in some cases, work; they often develop naturally with minimal assistance or guidance from humans (or from humans using traditional rather than modern breeding methods), hence are usually older, less modern races.

....The effect of any harmful or undesirable genes becomes noticeable in later generations.... as the majority of the offspring inherit these genes.... 

Scientists have discovered that Wolves, even if living in different areas, are genetically very...very similar. Quite obviously the gradual and relentless desolation of their natural habitat has drastically reduced wolf numbers in the past creating a definite genetic bottleneck. 

...Let's look at the Wolf....:the lack of genetic diversity makes them susceptible to disease... since they lack the ability to resist certain viruses. 

Extreme inbreeding affects their reproductive success with small litter sizes and high mortality rates.....Some scientists hope that they can developed a much more varied gene pool by introducing Wolves from other areas into the inbred Wolf Packs....

Cannabis can also suffer from being inbred over a protracted period of time by loosing hybrid vigor and often developing various mutations of growth....

Another animal suffering from the effects of inbreeding is the Giant Panda. As with the Wolf, this has led to poor fertility among Pandas and high infant mortality rates. As Panda populations become much more isolated from one another (mostly due to humans blocking the routes which Pandas once used to move from one area to another).....Sadly as a result Giant Pandas have greater difficulty in finding a mate with a different mix of genes and breed much less successfully..... 

Within cat populations natural isolation and inbreeding has given rise to domestic breeds such as the Manx cat which developed on an island (Isle of Man) so that the gene for tailless ness...(having no tail!....Meooow!) became widespread despite the many problems(for the cat)... associated with it. 

...Apart from the rare odd cat jumping off a ship on the Isle of Man, there was little out crossing and the effect of inbreeding is reflected to this day in smaller than average litter sizes,...stillbirths and spinal abnormalities which diligent cat breeders have worked so hard to eliminate.....

Some feral cat colonies have become highly inbred due to being isolated from other cats (e.g. on a remote farm) or because other potential mates in the area have been sterilized/neutered so removing them from the immediate gene pool. 

Most cat workers dealing with feral or wild cats have encountered some of the effects of inbreeding. Within such colonies there may be a higher than average occurrence of certain traits..... Some are not serious, for example: A predominance of calico pattern cats. 

Other inherited traits which can be found in greater than average numbers in inbred cat colonies include polydactyl (the most extreme case reported so far being an American cat with 9 toes on each foot!!), dwarfism (although dwarf female cats can have problems when trying to deliver kittens due to the kittens' head size), other structural deformities or a predisposition to certain inheritable conditions. 

The ultimate result of continued inbreeding is terminal lack of vigor for cannabis or cats and probable extinction as the gene pool contracts, fertility and natural vigor decreases, abnormalities increase and mortality/mutation rates rise.

SELECTIVE BREEDING.......

...Artificial Isolation or 'Selective Breeding' produces a similar effect. When creating a new breed from an attractive mutation....

Here the gene pool is initially necessarily small with frequent crossings between related plants. Some varieties which resulted from spontaneous mutation have been fraught with problems........If we were talking about dogs we would look at problems such as hip dysplasia in the German Shepherd and Patella luxation which are more common in certain breeds and breeding lines than in others, suggesting that past inbreeding has distributed the faulty genes. 

Selecting suitable outcrosses can reintroduce healthy genes, which might otherwise be lost, without adversely affecting the strain/breed as long as the outcross has mostly recessive traits.... 

Most all zoos that are engaged in captive breeding programs are aware of this need to outcross their own stock to animals from other collections.

...Captive (closet) plant or animal populations are at risk from inbreeding since relatively few mates are available to the animals/plants, hence zoos must borrow animals from each other in order to maintain the genetic diversity of offspring....and cannabis cultivators might share clones or seeds..... 

It's plain to see that inbreeding holds problems for anyone involved in animal husbandry or cannabis cultivation - from canary fanciers to alfalfa farmers. 

When certain dog breeders attempted to change the appearance of the Pug dog so that it would have a flatter face and a rounder head, this resulted in more c-sections being required and other congenital problems. A few of these dog breeds are loosing there natural ability to give birth without human assistance!....

In the dog world, a number of breeds now exhibit hereditary faults due to the over-use of a particularly popular stud which was later found to carry a gene detrimental to health. By the time the problems came to light they had already become widespread as the stud had been extensively used to try to improve the breed. In the past some breeds were crossed with dogs from different breeds in order to improve the breed, but nowadays the emphasis is on preserving breed purity....... and avoiding mongrels. 

Those involved with minority breeds (rare breeds) of livestock and cannabis face a dilemma as they try to balance purity against the risk of genetic conformity. 

Enthusiasts preserve rare varieties of plants because their genes may prove useful to growers/breeders in the future, but at the same time the low numbers of the plants involved means that it runs the risk of becoming unhealthily inbred. 

When trying to bring a strain back from the point of extinction, the introduction of 'new genetics' through crossing with an unrelated strain is usually a last resort because it can change the very character of the strain/variety being preserved. In livestock, successive generations of progeny must be bred back to a purebred ancestor for 6 - 8 generations before the offspring can be considered truly purebred themselves.......With cannabis you could say that we can achieve virtual stability after 4 generations and any further generations in-bred there-off may show some form of in-breeding depression or could even show something better!! .....

In the 'fancy' dog category, breed purity is equally desirable, but can be taken to ridiculous lengths.....

Actually some fancy dog enthusiasts will not recognize 'hybrid' breeds such as the white or Parti-Schnauzer because it does produce variants. Breeds which cannot produce some degree of variability among their offspring risk finding themselves in exactly the same predicament as Wolves and Giant Pandas.... Such fancies have lost sight of the fact that they are registering 'pedigree' dogs, not 'pure-bred' dogs, especially since they may recognize breeds which require occasional out crossing to maintain the breed.. ....and so not exactly pure-bred....

Implications of in-breeding:

....Most cannabis breeders are well aware of potential pitfalls associated with inbreeding although it is very tempting for a novice to continue to use one or two closely related lines in order to preserve or improve a strain. Breeding to an unrelated line of the same strain (wherever possible) or out crossing to another variety (wherever permissible) can certainly ensure vigor. Despite the risk of importing a few undesirable traits which may take a while to successfully breed out, and here the skill and patience of the breeder comes much into play....

...OUT-CROSSING: can prevent a breed from stagnating by introducing fresh genes into the gene pool. It is important to outcross to a variety of different plants, considered to be genetically 'sound' .....(do any of their previous offspring exhibit undesirable traits?) .....and preferably not closely related to each other. 

How can you tell if a breed/strain or line is becoming too closely inbred?

..One sign can be that the variety or strain gets more prone too disease..... Mutations such as whorled philotaxy, unusual leaf shape and plant size (dwarfism or gigantism) and reduced calyx production/size can also effect fertilization and procreation as well as growth. There can also be an up-side where the plants can exhibit new and interesting colors/yeilds etc......you never can tell exactly what the plants will show through mutation.......it could be something that a breeder is looking for and is actually quite happy to find....

.....and back to dogs:....Small litter sizes and high puppy mortality on a regular basis indicates that a breed of dog could be becoming too closely related. The loss of a large proportion of dogs to one disease indicates that the dogs are losing/have lost what is called 'Immune System Diversity'. ....If 50% of individuals in a breeding program die of a simple infection, there is naturally much cause for concern for the dog breeder.... 

Highly inbred plant species also display abnormalities on a regular basis as 'bad' genes become more widespread. These abnormalities can be simple undesirable characteristics such as susceptibility to pests or lack of vigour to much more serious mutated deformities........

Sometimes a fault can be traced to a single male or female which should be removed from the breeding program even if it does exhibit exceptional type. If its previous progeny are already breeding it is very tempting for many breeders to think 'Pandora's Box' is quite obviously already open and the damage done so I'll turn my back on the truth!.......this is not good...

Ignoring the fault and continuing to breed from the plant will cause the faulty genes to become even more widespread in the line, causing problems later on if its descendants are bred together and the negative traits are not successfully bred out. 

Talking of cats, one breed which was almost lost because of inbreeding is the American Bobtail Cat..... Inexperienced breeders tried to produce a color-point Bobtailed cat with white boots and a white blaze that bred true for it's type and also color, but only really succeeded in producing unhealthy inbred cats with very poor temperaments.... 

....a bit later on... a breeder had to outcross the small fine-boned cats she had, at the same time abandoning the rules governing color and pattern, in order to reproduce the larger, robust cats required that were true to breed and once again get the breed on a sound genetic footing.......

Conclusion.....:

...Inbreeding is what you might call a two-edged sword. Upon reflection and on the one hand a certain amount of inbreeding can most definitely fix and improve a variety/strain or breed tremendously to produce excellent quality plants or even animals........On the other hand, excessive inbreeding can limit the gene pool so that the breed loses any vigor what-so-ever. 

....Strains in the early stages of development are most vulnerable as populations can be small and the plants may be closely related to one another. It is up to the responsible breeder to balance inbreeding against various crossings with unrelated plants in order to maintain the overall health of the line/strain or breed concerned........

...Inbreeding can produce outstanding results initially....but eventually to maintain distinct vigor it is absolutely necessary to introduce new genetic material to prevent in-breeding depression and eventual extinction of the line.......Once again here the skill of the breeder comes into play to try and preserve the line by introducing plants that mostly have recessive traits that will not dominate when paired with the in-bred line....


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## Blazed763 (Apr 1, 2009)

Hi,

Thank you for this article.

If i took two bad quality unrelated seeds and keep breeding them with eachother under optimal growing conditions will the genes improve continously or will it hit the roof eventually?

Thank you


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## Grubs (Apr 16, 2009)

All genes available to you are in the seeds you start with (mutants not withstanding). With breeding you are just trying to pick out the best genes and get them together in the same plant. Some are "hidden" and some show (in the parent plant).


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## Grubs (Apr 16, 2009)

The article is pretty down on inbreeding, but keep in mind, that's you need some to create a new strain or breed.


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## desert fox (Apr 17, 2009)

very good reading. I am curious about IBL and different breeders.

Lets take bubblegum for example. Serious Seeds and TH Seeds carry bubblegum. Is one considered better, or are they pretty much the same quality? 

Or a better example would be Afghani. A few breeders carry it.....Is one nessarily better or worse? After all it is a landrace strain. Price is definitely different.


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