On the Evaluation of Koi
from A Genetic Point of View.
by: Dr. Mao-Lin Tsai, Nishikigoi Society of Taiwan
Assisted by Ronnie Watt, S.A.K.K.S.
From an article published in KOISA magazine.
Tsai's Three Laws of The Genetics of Koi
Law 1: The greater the genetic potential to achieve Jumbo Size, the less the genetic potential to achieve good quality and pattern.
Law 2: Hi and Sumi are genetically speaking in competition with one another.
Law 3: Hi is genetically stronger in the anterior (front part) of the body and sumi is genetically stronger in the posterior (back).
The evaluation of Koi is no simplistic matter and even the most experienced of Koi keepers can err.
The system of evaluating the true qualities of a Koi is not confined to assessing the immediate and obvious factors - for proper evaluation one has to bring into consideration the following:
* the price which equivalent quality fish has achieved in the past.
* the economic status of the breeder,
* national socio-economics,
* the potential of the fish as a show winner,
* the sex and age of the fish,
* the condition of finish of the fish,
* past history of the fish,
* availability of variety, patterns and quality and,
* the potential of the fish to grow to jumbo size.
The economic factors mentioned are ever changing and can be
influenced. What can not be changed and which must therefore have priority in
the evaluation of a fish, are hereditary factors of the fish. Heredity will
influence quality, pattern and Jumbo-potential and such potential will be
passed on by the parent fish.
The present-day Koi has been much refined and Koi keepers tend to
forget that the Koi's roots are in the true carp. The true carp has the
potential to grow to jumbo size. If a true carp is bred with a modern Koi, 95%
of the fry will have true carp characteristics. Unfortunately, there are only a
few breeders who breed their Koi from parent stock which are genetically close
to the true carp and which, therefore, will breed off spring with the true
carp's qualities of the potential to grow to Jumbo size.
In Taiwan the true carp has itself undergone some change - it has
become fat and short in body shape. In the process of breeding and refining
varieties of Koi, we have striven to increase the quality of the Koi - but in
the process we often sacrifice the true carp quality of potential Jumbo size.
When the breeder strives to breed Koi with Jumbo size, he might sacrifice
quality but gain Jumbo offspring.
Beautifully balanced patterned Kohaku will produce 2-step 3-step,
4-step and 5-step offspring. Such offspring will boast high quality, but will
genetically be far removed from the true carp and therefore lack the potential
to grow to Jumbo size. If such offspring do grow to Jumbo size, their quality
will greatly diminish. The higher the quality of a Koi, the more distant the
genetic relation with the true carp.
The challenge lies in securing Koi with Jumbo potential
(genetically closer to the true carp) but at the same time securing quality.
If the genetic potential of a Koi is being evaluated, it must be
done according to the genetic qualities associated with the true carp.
* As regards Jumbo potential:
The closer the Koi's genetic source is to that of the true carp, the greater the potential; for a Koi to grow to Jumbo size. However, the quality and pattern of such a Koi will not be of a high standard.
* As regard competition between the hi (red) and sumi (black):
Both hi and sumi have a genetic tendency to dominate the other.
Therefore, we must assume that better the balance between the presence
(quality) and the pattern (distribution) of the hi and sumi, the poorer the
genetic quality of the hi and sumi will be.It is near impossible to find a Jumbo Koi with equal quality of hi
and sumi. In some smaller Koi one will indeed find equal quality of hi and sumi
- but this is achieved through the finishing technique (slow growth and early
maturation) and must therefore be considered unstable.
* As regards strength of the hi (red) and sumi (black):
Hi is stronger in the anterior (front part of the body and the sumi is stronger at the posterior (back),
What do these inherent genetic qualities imply?
* Jumbo parent stock are genetically related to the true carp. They have the genetic potential to produce Jumbo offspring but the percentage of offspring with good quality and pattern will be small.
* Parent stock with very high-quality good pattern have the genetic potential to produce a large percentage of offspring with good quality and pattern but the offspring will have less potential of developing into Jumbo Koi.
* The best quality of hi and sumi are those which do not have an
absolute even balance - one of the two must tend to dominate as an indication
of it's genetic strength.
In conclusion, the evaluation of a Koi must specifically focus on
inherent genetic potential. If a young Koi shows little of the genetic
qualities which can be traced back to the true carp (quality, colour, pattern,
growth potential) it will not grow into a quality sized Jumbo Koi.
The young Koi must reveal the potential of quality of hi and sumi and a strength of hi and sumi. These can be determined from the viewing of the young Koi. Just as important is to enquire about the qualities of the parent stock: their size and quality. If the parent stock is of jumbo size, the young Koi has the potential to grow to the same size but the quality will be difficult to achieve. If the parent stock is smaller but can be noted for high quality but not for size, the offspring will most likely reflect the same characteristics