Inheritance of blackspot bruise resistance in potato

Inheritance of blackspot bruise reaction in tetraploid potato was studied using a five-parent half-diallel, including parental selfs. The parents were chosen to represent the full range of blackspot reactions. Four 12-plant replications of each family were grown at Aberdeen, Idaho and at Prosser, Washington. The abrasive-peel method was used to evaluate the blackspot reaction. Highly significant general combining ability (GCA) effects and specific combining ability (SCA) effects were observed for this trait. The GCA and SCA variances represented 59% and 9%, respectively, of the total variance. GCA effects are presented for the parents. The narrow sense heritability was 0.85. These results indicate that breeding for resistance to blackspot should be successful if resistant parents are used; backcrossing may be needed.