Impacts of genetic selection on Sequoia sempervirens mini-cutting rooting and initial growth in the field

Background: Vegetative propagation from superior individuals allows multiple copies of plants that are genetically identical to the parent plant to be obtained. However, vegetative propagation success varies among individual genotypes, with some clones having more difficulty forming roots than others. The aim of this study was to evaluate the genetic gain in Sequoia sempervirens (D.Don) Endl. clones using parameters describing vegetative propagation success and initial growth in field. Methods: Vegetative propagation success was quantified for 16 clones in a completely randomised design consisting of 10 replications, each containing 10 mini-cuttings. At 90 days, rooting (RT), survival (SV) and the number of new shoots (NS) were evaluated. Performance after planting in the field was assessed using 13 clones from the previous experiment, arranged in linear parcels of 10 plants with 8 replicates. After 18 months, survival (SV), stem diameter (SD), height (H) and dominance breakdown (DB) were assessed. Estimates of variance components, heritability and genetic correlations were obtained using the Selegen-REML/BLUP software. Results: The mini cuttings of the 16 clones had a coefficient of genetic variation (CVgi%) of 32.32% for RT, 5.44% for SV and 5.35% for NS. The heritability of the total genetic effects (H2 g) for RT was 0.68. The clones with the best predicted genotypic classifications for the characteristics evaluated in the field were A116, A140 and A138 for SV, A126, A140 and A138 for SD, A138, A140 and A117 for H and A138, A228 and A116 for DB. Conclusions: In general, it was possible to obtain high genetic gain for rooting and medium gain for dendrometric variables in the field.