by
K.A. Golovinskaya
All Union Pond Fishery Institute
Moscow, U.S.S.R.
Efforts to create a mid-Russian carp breed have been carried out since 1960 at Yakots Experimental Fish Farm of the Institute of Pond Fishery, in the suburb of Moscow. The new breed is intended for the central areas of the U.S.S.R.
The structure of this breed is planned to be a combination of several breeding lines similar in their productive properties but different in their features and characters. The breeding lines under formation are supposed to be utilized in commercial double-cross breeding (Shaskolsky, 1954), which is recommended now in carp culture with a view to avoiding close inbreeding and to obtain heterozygous combinations (Golovinskaya, 1962).
Four groups of spawners, different in origin, were used as initial material for selection. When preparing the pedigree stock we tried first of all to increase genetic variability of the breeding lines (Kirpichnikov, 1966). Therefore, the first step in our work was the formation of the double-crossed lines by means of selecting parents of different origin. Having in our possession a stock of the double-crossed lines, we could go on to the next stage of creation of more complicated three-way and four-way crossed lines designed for moulding a nucleus of pedigreed stock for future breeding.
The experiments of the first stage are comprehensively described in a cooperative report to be published in the transactions of the Institute of Pond Fishery (Vol.16 - Golovinskaya et al., in press). The second phase started in 1966 and is still very far from completion.
The breeding lines obtained represent good material for further work. Therefore we did not set out to study them in detail. In recent years, however, new evidence has been obtained which characterizes some features and differences of the pedigreed groups depending on their origin. This has provided us with certain starting points for further selection work and allowed us to outline in the first approximation what the composition of the initial pedigreed nucleus of a future strain should be.
The general extent of our work was conditioned mainly by the facilities available at the experimental station. Yakots fish farm is not, unfortunately, a specialized pedigree-selection station. It is intended for various kinds of investigations envisaged by the long-term subject plan of the Institute. Therefore we had to confine ourselves to a lesser volume of experimental work on crossings and to keep only a part of the forms obtained for further breeding.
Two groups of spawners were represented by pure carp without any trace of inheritance of wild carp. This property was considered of great importance for the experiments.
It is known that an exaggerated interest towards hybridization of cultured carp with its wild counterpart (mostly Amur wild carp) had led to a situation that made it almost impossible to find pure carp in the cultivated stocks, at least within the Russian Federation. A group of pure carp was introduced to Yakots from the Ukraine (Ostrozhany fish farm, Cherkass District) and a second group of carp was brought from Niva fish farm (Voronezh District). The latter were derived from the local stock which recently has been replaced completely by hybrid Kursk carp (a few of the local stock have been preserved in an affiliated station).
Kursk carp are also among the four parental groups. They were introduced into Niva station for trials, but we do not possess precise data on the origin of this carp in order to establish the degree of Eastern carp's heritage in them. In the life history of this breed-group there are records of back crossings of F hybrids with Eastern wild carp, and crosses of these hybrids with each other. The intermixing of carp stocks in the years of the war is also of importance, particularly in fish farms of Kursk District where this group was formed (Golovinskaya, Panina and Shaskolsky, 1947).
The similarity in body structure of Kursk spawners (including specimens studied in some fish farms of Kursk District) to northern Ropsha carp leads us to believe that the share of Eastern wild carp's heritage in Kursk carp should constitute about 70–80 percent.
The fourth group of the parental stock consisted of Zagorsk carp reared on an experimental fish breeding farm at Zagorsk (Moscow Area). The presence of wild carp's features is not ruled out, because crossings with Eastern carp and earlier with Volga wild carp, had been widely practised in the Moscow Area.
Among the four groups, the Ukrainian and Kursk spawners showed a greater difference in their appearance. The Ukrainian had the most noticeable carp-like body conformation, although they did not represent the elite of the Ukrainian selected breeds. They were noted for a high and comparatively short body. Kursk carp with long bodies constitute the other extreme group representing a wild-carp-like body structure.
The following are some comparative characteristics of Ukrainian and Kursk carp (measurements taken in 1963):
| Ukrainian | Kursk | |||
| females | males | females | males | |
| Weight in kg | 5.9–9.2 | 5.3–5.9 | 4.7 | 3.9 |
| Body length in cm | 52.5–63.0 | 54.5–55.0 | 56.0 | 57.0 |
| Condition factor | 3.7–4.1 | 3.2–3.6 | 2.7 | 2.1 |
The Niva and Zagorsk spawners occupied an intermediate position and did not differ significantly from each other in body conformation.
One female and one male of Kursk carp (both scaled) have proved to be homozygous (SS), although carp with scattered scales are encountered quite regularly in Kursk stocks; hence, heterozygosity of scaled Kursk carp is not ruled out. Niva carp are represented by one scattered carp (ss), although scaled carp also occurred in Niva foundation stock.
The Ukrainian spawners (2 ♀♀ and 2 ♂♂) consisted solely of scaled carp (specimens with scattered scales were introduced, but they did not endure transportation). The analysis of the progeny showed that all our Ukrainian scaled spawners were heterozygous (Ss). Therefore, we now possess scattered carp of that group also. The Zagorsk strain was represented both by scaled (all of them heterozygous Ss) and scattered carp.
The work was started by obtaining the single-crossed lines for reproduction of the parental groups. Later we proceeded to the formation of the double-crossed lines.
The first line was obtained with the Kursk carp. This was necessary because of the availability of only a single pair of spawners (due to sanitary regulations the possibility of new arrivals was excluded). Besides, we hoped to trace signs of heterosis in the progeny resulting from such crosses. It was also of interest to watch the development of the wild carp's characters in crosses of various combinations. The same factors were considered in crossing Ukrainian carp. In the beginning the crossings were carried out only by natural spawning which considerably delayed our work, especially when the number of spawners was limited. Later we used artificial fertilization making the eggs non-adhesive by washing in solutions of salt and urea and hatching them at the plant.
The lines obtained were denoted according to their origin by the first letters
of the names of the parental groups; K for Kursk, N for Niva, U for Ukrainian, Z for
Zagorsk. Thus, for example, the double-crossed lines N-K and Z-K were obtained by
crossing Niva and Zagorsk females with male Kursk carp. Fractions were used for
designating additional strains. For instance, the four-way cross 
originates from
the selection of the spawners of the double-crossed lines N-K
and Z-U; females are always designated in the numerator and males in the denominator.
The number of fishes raised in each line was different, and was determined chiefly by the nursery facilities. In the process of rearing, the number of specimens declined when a part of the yearlings was transferred for fattening and later when the fish were older (at the time of maturation).
It has to be emphasized that selection (mass) was performed to a very limited extent. We tried our best to preserve the stocking material in its whole diversity. For example, yearlings intended for further breeding were grouped under the principle of selection of the mean sample, discarding defective fish only. Two-summer-olds were selected by weight in a few breeding lines (not exceeding 25 percent). Young spawners were selected on the basis of general condition or sexual expressiveness rather than by weight.
Survival of fingerlings varied within a wide range, declining sharply when fingerlings were reared with adults. Survival rates of two-summer-olds and the replenishing stock of older fish were quite high and did not vary considerably.
Distinct differences pertaining to the origin of the hybrid lines were not observed here. The loss of some Niva three-year-olds was due to infection by Khavio sinensis; in the three-year-olds of Kursk origin stocked in the same pond, no loss was recorded.
Differences in weight can hardly be attributed to inborn features of the hybrid lines; they result chiefly from different feeding conditions. The fluctuations in weights of yearlings are rather noticeable and directly related to stocking density. Mean weights of the two-year-olds are more even, attributable to more uniform conditions of rearing. The density of stocking and food ration were calculated for the two-year-olds assuming a 700 g weight increment.
At older ages the fluctuations in weight were more conspicuous than in the two-year-olds. Starting from the age of three the Ukrainian specimens have greatly surpassed their counterparts derived from crosses K-U and Z-K, although the latter were raised in the same pond.
In hybrids with Kursk carp the heterosis effect has not been observed. The hybrid line K-U has proved to be the most inferior in growth and greatly susceptible to infection by Ichthyophthirius which affected many fish farms including Yakots in the summer of 1964.
More distinct and definite differences were established in the peculiarities of the air bladder structure and conformation characteristics. In this respect, all hybrid forms of single and double crosses were clearly distributed into two groups which differed in origin. The first data on the morphometry of air bladder were obtained from the fall survey in 1963 (Golovinskaya, 1965). Both chambers of the air bladder were measured and three factors calculated; they show the ratio between the length of the posterior chamber and the length of the anterior chamber, and the ratio of the length of each chamber to the body length. The distinction between these indices has proved to be very marked, especially between pure Ukrainian and Niva carp and Kursk carp. The scattered Ukrainian carp group have the posterior chamber shorter than the anterior, whereas in Kursk carp the posterior chamber is the longer. This fact makes them closer to Amur wild carp. The mean readings for the three factors are given below:
| Ukrainian carp with scattered scales | Kursk carp | |
| Length of posterior chamber | 81.2 ± 4.45% (from 59 to 103%) | 118.0 ± 6.23% (from 104 to 144%) |
| Length of anterior chamber | ||
| Length of anterior chamber Body length | 20.1% | 18.0% |
| Length of posterior chambe Body length | 16.2% | 20.7% |
The double-crossed hybrids occupied the intermediate place, showing a clear tendency toward hybrids obtained from the crosses with Kursk carp (it was particularly conspicuous in the K-U cross where the female was of Kursk origin).
Most of the hybrid groups were examined a second time in 1964, and some additional data were received on groups which had not been investigated earlier. Carp from two Zagorsk groups (scaled and, particularly, scattered) were found to be clearly of the carp type, like the Z-U group. The division of groups, according to the structure of the air bladder, generally remained the same, except that the U-K group was closer to the carp type than to the hybrid type, unlike the K-U group (from reciprocal crossing). The ratio of the length of the posterior chamber to the length of the anterior chamber in the first case averaged 94.7 percent (ranging from 74 to 120 percent) and 118.0 percent ± 2.6 percent (range 103–144 percent) in the second case. It is presumed that this is due to matroclinal inheritance which is common in such hybrids.
The carp type, with a relatively short and high body, has a longer anterior chamber whereas the longer posterior chamber is characteristic of the hybrid type (crosses with Amur wild carp) which has a long body.
Comparison of the above ratios with body conformation factors showed that carp and hybrid groups are distinguishable not only on the basis of the morphometry of the air bladder but also with respect to body characters. These are especially distinct in the two extreme groups - Ukrainian and Kursk.
It appeared possible to gain a better knowledge of the nature of inheritance in hybrid groups on the basis of bladder characters than of body conformation characters. Thus, for example, Niva and Zagorsk carp, according to the type of the air bladder, were closest to Ukrainian carp with scattered scales; whereas their body features showed a less pronounced carp type. Well growing two-year-olds of the N-K group had the absolutely carp-like conformation, and only indices of the air-bladder pointed to their hybrid origin. The expressiveness of body features undoubtedly depends greatly on age and general condition of fishes, although hereditary properties can manifest themselves here quite clearly.
Relative length of intestines can also be considered a diagnostic character for distinguishing pure carp and hybrid groups (though this character is not so stable as that of the air bladder) as observed recently in carp of Niva and Kursk groups (Popova, 1967).
Towards the end of the first stage of our work we had single lines of each initial group and a number of double-crossed lines. Among them were a pure carp group N-U (scaled Ss and scattered), carp group Z-U (scaled SS and Ss and scattered) and four hybrid groups Z-K (scaled Ss), N-K (scaled Ss), K-U (scaled SS and Ss) and U-K (scaled SS and Ss). But it was not possible, nor expedient, to create and test all the numerous combinations that are possible from such a diversity of material.
Two carp lines (N-U, Z-U) and two hybrid groups (Z-K, N-K, which were the best varieties, were preserved for the second stage of experiments.
The stock of single and double-crossed lines allows us at this stage to have two categories of combinations of four initial groups. The first category is composed of the three-way crossed lines, in which the heredity share of one group constitutes 50 percent and the other two 25 percent each. The other category comprises of the four-way crossed lines in which inheritance of the four groups is represented equally, being 25 percent each.
The three-way crossed lines were obtained in 1966 and 1967 (Table I). It is seen
from the table that the heredity share of the Kursk group reaches 50 percent in one
line (cross No. 3 
); in all other groups it reaches 25 percent, with 50 percent
inheritance of Ukrainian and Zagorsk carp.
Under the conditions prevailing in the middle region of Russia it was not considered necessary to produce a greater number of lines with a large share of Eastern wild carp's heredity transmitted by Kursk carp. Experience has shown (investigations carried out at Para fish farm, Ryazan District) that best results are obtained when the share of Eastern carp's heredity is 25 percent. We believe that this limit is to be observed for our breed. Niva group does not play a leading part in the formation of complex lines. This group is of pure carp origin, though it proved to be less resistant to diseases and not sufficiently tolerant. We limited its inheritance in three-way crossed lines, and we preferred Ukrainian and Zagorsk carp in appropriate combinations.
The four-way crossed lines were obtained in 1967 from two combinations of crossing spawners of the N-K and Z-U lines (crosses 5 and 6, Table I).
We regard all these complex lines as first hand material for formation of a nucleus of a future pedigree breed. We missed several lines that were free of Kursk carp's participation, and hope to obtain them in 1968 by means of two crossing combinations of females from the Z-U line with males of the N-U line. The N-U line is the youngest, and in the next year only males can be used for crossings. We plan to arrange one combination of scaled spawners and the other of scattered carp.
The structure of the future pedigreed nucleus may be visualized as a combination
of eight lines: four of them will be composed of scaled carp (SS and Ss) and the other
four of carp with scattered scales (ss). The list of lines, with indication of
heredity shares of parental groups, is set out in Table II. The table is arranged so
as to emphasize the differences in genotypic structure of the breeding lines, starting
with the three-way crossed line of scaled carp (where the heredity share of Kursk
carp and, consequently, that of Amur wild carp is largest) and ending with the three-way
crossed lines of scattered carp with prevaling inheritance of Ukrainian carp.
Future work will be devoted to selection within the lines and, first of all, to detection of homozygosity of scaled carp on a progeny basis. Along with this, the comprehensive studies of the lines' characteristics (including determination of heritability) and estimation of their productive properties will be conducted.
Table I
Data on origin and composition of complex breeding lines created in 1966/1967
| Numbers and years | Selection of spawners by origin and by scale pattern | Heredity share of spawners in breeding lines | Segregation in breeding lines rounded in percent | Included into the composition of pedigree stock for eventual breeding | |||||
| Females | Males | Kursk; | Zagorsk; | Niva; | Ukrainian | Scaled | Scattered | ||
| 1 1966 | U SS1 | N-K Ss | 25 | - | 25 | 50 | 50 | 50 | scattered ss |
| 2 1966 | Z ss | N-K Ss | 25 | 50 | 25 | - | 50 | 50 | scattered ss |
| 3 1967 | Z-K Ss | Z-U SS | 25 | 50 | - | 25 | 100 | - | scaled SS and ss |
| 4 1967 | Z-K Ss | N-K Ss | 50 | 25 | 25 | - | 75 | 25 | Scaled SS and ss |
| 5 1967 | N-K Ss | Z-U Ss | 25 | 25 | 25 | 25 | 75 | 25 | scaled Ss and ss |
| 6 1967 | Z-U ss | N-K Ss | 25 | 25 | 25 | 25 | 50 | 50 | scattered ss |
1 ss - scattered
SS and Ss - scaled
Table II
Initial composition of pedigree stock for creating Mid-Russian carp breed
| Nos and year of origin1 | Breeding lines | Scale covering | Heredity share of initial spawners (in percent) | |||
| Kursk | Zagorsk | Niva | Ukrainian | |||
| 4 1967 | | scaled SS and Ss | 50 | 25 | 25 | - |
| 3 1967 |  | scaled SS and Ss | 25 | 50 | - | 25 |
| 5 1967 | | scaled SS and Ss | 25 | 25 | 25 | 25 |
| 7 Plan for 1968 |  | scaled SS and Ss | - | 25 | 25 | 50 |
| 2 1966 |  | scattered ss | 25 | 50 | 25 | - |
| 6 1967 |  | scattered ss | 25 | 25 | 25 | 25 |
| 1 1966 |  | scattered ss | 25 | - | 25 | 50 |
| 8 Plan for 1968 | | scattered ss | - | 25 | 25 | 50 |
1 Numbers according to Table I.
Changes in the backbone of the pedigree stock can certainly occur, but they must not be radical, and should be directed at decreasing, not increasing, the number of lines.
In the event of a necessary alternation (for example, when emergency arises to change the proportion of heredity shares of parental forms) we possess a stock of lines which is replenished regularly. There are good breed-groups in that stock, such as Zagorsk scaled carp, from which homozygous spawners could be selected.
One can visualize a very wide programme of investigations connected with the creation of a new breed, but we are still in the second phase of experiments which can be considered completed when the breeding lines are represented by adult, mature fishes.
Golovinskaya, K.A., 1962 Breeding in pond fish culture. Rybovod i Rybolov., (10):7–10
Golovinskaya, K.A., 1965 On selection significance of air bladder of carps. Trud.vsesoiuz. nauch.-issled.Inst.prud.ryb.Khoz., 13:97–103
Golovinskaya, K.A., K.A. Panina and D.V. Shaskolsky, 1947 Stock of spawners and replenishing fishes in carp breeding farms of the Russian Federation. Trud.vseross. nauch.-issled.Inst.prudov.ryb.Khoz., 4:115–41
Golovinskaya, K.A., et al., 1969 Formation of carp pedigree stock at “Yakots” fish breeding station and some peculiarities of its composition. Trud.vsesoiuz.nauch.-issled.Inst.prud.ryb.Khoz., 16 (In press)
Kirpichnikov, V.S., 1966 Goals and methods of carp selection. Izv.gosud.nauchno.-issled. Inst.ozer.rech.ryb.Khoz., 61:7–27
Popova, A.A., 1967 Variations in relative length of intestines of “Kursk” and “Niva” carps. Thesisy konfer.molod.-spezialist.prudov.ryb.Vsesoiuz.nauch.-issled.Inst. prudov.ryb.Khoz., Rybnoe: 53–4
Shaskolsky, D.V., 1954 On close breeding of carp at commercial fish farms. Trud.vseross. nauch.-issled.Inst.prudov.ryb.Khoz., 7:22–33
