Trends in genetic and environmental parameters, genetic correlations, and response to indirect selection for 10-year volume in a Norway spruce clonal experiment

Abstract

Seventy-five clones of Norway spruce (Piceaabies (L.) Karst.) were tested for height, diameter, and volume at two locations in southern Sweden. Total height was measured at seven ages from age 1 to 10 years, whereas diameter at breast height was measured and volume index calculated only at age 10. Clone effects were consistently significant for all traits, whereas clone × location interaction effects only showed significance for diameter at breast height at age 10, volume index, and height at age 3. Location effects for height were small and error effects large, up to age 6. Between ages 7 and 10, location effects increased considerably, while error effects decreased correspondingly. Clone-mean heritability for height remained stable from years 3 to 10, but was slightly higher at age 1. Genetic correlations between traits were generally large, which made efficient selection for height possible as early as age 4. The correlated response in volume index at age 10, when selecting for height at age 4 or later, was exceptionally good, and it provided gain estimates in volume that were as large as or larger than estimates from direct selection for volume index at age 10.

Advantage of clonal deployment in Norway spruce (Picea abies (L.) H. Karst)

“…Estimates of h 2 for tree height were lower (0.04-0.07) than the values of other published results with seedlings using joint-site models for Norway spruce (Chen et al 2015(Chen et al , 2017Skrøppa et al 2015). Estimates of H 2 for tree height were in the range 0.12-0.16 which is comparable with other studies, such as 0.13 for tree height at age 6 (excluding G × E) (Karlsson and Högberg 1998), 0.17-0.29 for tree height at age 9 (including G × E) (Högberg and Karlsson 1998), 0.25-0.29 for tree height at ages 3 to 10 years (Bentzer et al 1989), and 0.09-0.43 for tree height at ages 9 to 18 years (including G × E) (Högberg and Dutkowski 2010), and 0.10-0.22 for height at age 17 (including G × E). Compared with those published studies with high prior intense selection in the nursery, the difference here may be that only a slight prior selection was performed and that may produce less bias in the estimation of h 2 and H 2 .…”

“…The Swedish breeding program for Norway spruce has been focused on growth, survival, branch quality, and wood density (Rosvall et al 2011). Genetic parameters have been estimated for many full-sib and half-sib seedling progeny trials (Hannrup et al 2004;Kroon et al 2011;Chen et al 2014) and also for clonal trials, but without family structure (Bentzer et al 1989;Karlsson et al 2001;Högberg and Dutkowski 2010;Isik et al 2010). A most recent study of Norway spruce in clonal trials included family structure (Berlin et al 2019), but considered just growth properties.…”

Genetic Control and Nursery-Plantation Genotypic Correlations for Growth Characteristics of White Spruce Somatic Clones

“…In clonal tests of balsam fir (Picea abies [L.] Karst) produced from rooted cuttings, Isik et al (2010) also observed that height at 5 yr was highly correlated with that at 3 yr (r G = 0.85). Genotypic correlations between height at 4 yr of age Norway spruce clones and heights at later ages all equaled or exceeded 0.95 (Benzer et al, 1989). These authors provided that the early selection for height at age 4 was good predictor of larger volume index at age 10.…”

“…The H c 2 values in the nursery are similar to the clonal heritabilitie for the height of on1-yr-old Norway spruce (Picea abies [L.] Karst.) grown from cuttings (H c 2 = 0.40; Benzer et al, 1989). On both two planting sites, the clonal heritabilities for height-calculated at 1, 2, 3, and 4 yr after outplanting in the present study-are lower than the individual heritabilities (h 2 = 0.40 to 0.65) of 9-yr-old plantation-grown white spruce in different regions of Ontario (Lake Tomahawk, Wabeno, Moran; Nienstaedt & Riemenschneider, 1985).…”

“…However, selection of only the very best clones may make the process long and costly depending on the species and specific characteristics that are being sought (Benzer, Foester, Hellberg, & Podzorski, 1989;Carter, Adams, Greenwood, & Nitschke, 1990;Baltunis, Wu, Dungey, Mullin, & Brawner, 2009;Isik, Kleinschmit, & Steinner, 2010). Selection for desired genetic characteristics at a very young age, when the plants are still in the nursery and being grown under optimal cultural (e.g., irrigation and fertilization) and uniform environmental conditions, permits the poorest performing genotypes to be eliminated and the elite genotypes to be tested over the longer term for the targeted characteristics (e.g., good form, height growth, fewer branches, good root development, needle length, rootability of cuttings, resistance to insects and environmental stress, photosynthetic capacity, etc.).…”