Variation of the quantitative traits in a progeny test of Abies alba (Mill.) at the nursery stage

Abstract

Abstract Fifty-one full-sib families were created using 11 parents in a silver fir seed orchard and a half-diallel mating design. The seeds of control-pollinated families were sown in a nursery in autumn 2007. Growth and branches traits were measured during nursery testing, and genetic parameters were estimated at the ages of 3, 4, 5, and 6 years. The additive and dominance genetic variances were major sources of genetic variance. Dominance variance was greater than additive variance at these early ages for all traits. However, the ratio of SCA/GCA variance decreased from 23 to 14 for total height and from 36 to 19 for root collar diameter. Broadsense family heritability is higher than individual heritability. Height and root collar diameter are the most heritable traits in silver fir. The time trend of the five heritability estimates for total height increased with age. Significant trait-trait genetic correlations were obtained. Age-age genetic correlations were very high, and they displayed increasing trends with age. The selection of the most valuable parents and most valuable individuals within the best families could maximise genetic gain in the second breeding generation of silver fir.