Diallel crosses in <i>Picea abies</i> IV. Genetic variation and inheritance patterns in short-term trials

Abstract The complete diallel cross is the only mating design that provides estimates of variance components general combining (GCA), specific ability (SCA), maternal and reciprocal effects, in addition to heritabilities genetic correlations. To obtain such estimates, diallels were made among 10 trees each three natural Norway spruce populations from altitude 300 500 m southern Norway. Seedlings families open pollinations tested short-term tests on agricultural soil at one site 85 until age years seed. Tree height ages 7 diameter had strongly significant GCA within population. for SCA effects small not significant, indicating low levels non-additive variation. For days initiation cessation shoot elongation period dominating highest heritability two diallels. Estimates correlations between traits measured earlier nursery trials consistent values duration growth rate showed positive relationships with diameter. Strong present half-sib family means open-pollinated height, phenology traits. Progeny testing can be used selection candidates initial breeding populations.