The study was carried out in the pedigree herd of 41 boars of the Polish Landrace breed kept at the Breeding and Insemination Station. During the reproduction period 3388 eiaculates were taken and subject to analysis and assessment and the semen concerned was used to inseminate sows serviced by the station. The PCR-RFLP method was used to determine the frequency of mutation 1843C→T in gene RYR1, the said mutation being responsible for stress susceptibility of pigs. In the herd concerned genotype RYR1^NRYR1^N occurred at the frequency of 0.7317, genotype RYR1^NRYR1ⁿ at the frequency of 0.2683, whereas genotype RYR1ⁿRYR1ⁿ (animals susceptible to stress) was not found. Relations between RYR1 (RYR1^NRYR1^N and RYR1^NRYR1ⁿ) genotypes and qualitative and quantitative characters of semen such as eiaculate volume, concentration of sperm cells, a share of normozoospermia, the number of sperm cells in a dose and the number of insemination doses. The analysis of relations between RYR1 genotypes and the boar semen traits showed the clear and statistically significant (p = 0.01) predominance of the boars of RYR1^NRYR1^N genotype over the ones exhibiting RYR1^NRYR1ⁿ genotype in terms of eiaculate volume, share of normozoospermia, the number of normozoospermia in an eiaculate and the number of obtained insemination doses.

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