Microsatellites used to establish full pedigree in a half-sib trial and correlation between number of male strobili and paternal success

• Paternity was established in a field trial of Abies nordmanniana with open-pollinated (OP) offspring from a clonal seed orchard (CSO) comprising 23 clones. • The purposes were to: (1) investigate the violation of the assumption of true half-sibs in OP progeny trials; (2) assess the value of male strobili scorings to predict paternal contributions in CSOs; and (3) study the bias in breeding values and heritabilities obtained in breeding with OP family trials due to unknown paternity. • The paternal contribution to the offspring varied a lot among the clones, but the resulting violation of the assumption of true half-sibs in the progeny trial was only modest. • On average 84% of the relationships among the offspring were true half-sib, resulting in an average genetic correlation of 0.29 (range 0.26 to 0.33). • Male strobili scorings from the seed harvest year did well in forecasting the paternal contribution to the offspring. The linear regression of sired progeny on the estimated clonal proportion of male strobili explained 76% of the variation. • The large variation in siring success and existence of other types of relationships than true half-sibs among the offspring only gave minor bias in estimated genetic parameters