| Popis: |
The development of long-term work on common carp selection for resistance to dropsy, a very serious infectious disease, is reviewed. The work was initiated at the Angelinka Experimental Fish Farm (Krasnodar Region, North Caucasus) in 1965. The selection was carried out on three common carp stocks; local mirror carp (L), a full-scaled Ropsha Carp (R), and a new hybrid line of Ukrainian-Ropsha scaled carp (UR). The 8th and 9th generations of these three stocks were produced from 1986 to 1990. Further mass selection of fish for resistance to dropsy and for high growth rate was carried out. The severity of selection was moderate (30–35%) and, in the case of selection for growth rate, the intensity of selection (i) was from 0.5 to 1.0. Differences in resistance to dropsy between the three stocks were detected; the UR stock appeared to be most resistant. Genetic differences between stocks in allelic frequencies of some protein loci progressively decreased during the course of selection. Numerous tests showed that selection for resistance was effective. The selected stocks, especially UR fish and reciprocal UR × L crosses, are currently reared on many fish farms of North Caucasus. The major goals of future selection work with Krasnodar carp are: breeding of a UR stock homozygous for the gene S (full scale cover) to prevent undesirable segregation; conversion to the more effective family method of selection; obtaining detailed data on heterosis in crosses; analysis of the inheritance of high resistance to dropsy and determination of heritability; and detection and cloning of major genes responsible for high resistance to dropsy. |
