# Performance and Phenotypic Stability of Norway Spruce Provenances, Families, and Clones Growing under Diverse Climatic Conditions in Four Nordic Countries

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Materials and Methods

#### 2.1. Materials, Trials, and Measurements

#### 2.2. Measures of Phenotypic Stability

^{2}) [1]. These two measures are strongly related, and the latter will be used here. Both b and R

^{2}are independent of the units of measurements.

#### 2.3. Calculations and Statistical Analyses

#### 2.3.1. Provenance Data

_{ijk}= µ + P

_{i}+ S

_{j}+ PS

_{ij}+ B

_{jk}+ E

_{ijk}

_{i}is the fixed effect of provenance i, S

_{j}is the fixed site effect, PS

_{ik}is the interaction between provenance and site, B

_{kl}is the random block effect within site, and E

_{ijk}is the random error term.

#### 2.3.2. Family Data

_{ijkl}= µ + F

_{i}+ M

_{j}+ FM

_{i}

_{j}+ S

_{k}+ FS

_{ik}+ MS

_{jk}+ FMS

_{ijk}+ B

_{kl}+ E

_{ijkl}

_{i}is the effect of female parent i, M

_{j}that of male parent j, FM

_{ij}is the interaction between female parent i and male parent j, S

_{k}is the site effect, FS

_{ik}, MS

_{jk}, and FMS

_{ijk}are the three interactions with parents and site, B

_{kl}is the block effect within site, and E

_{ijkl}is the random within plot error term. All effects, except S

_{k}, are assumed to be random with expectations 0 and respective variance components. The analyses were made across all sites and with the two most extreme sites Lappkuliden and Imatra excluded.

#### 2.3.3. Clonal Data

_{ijkl}= µ + FA

_{i}+ C

_{ij}+ S

_{k}+ FAS

_{ik}+ CS

_{ijk}+ B

_{kl}+ E

_{ijkl}

_{i}is the effect of full-sib family i, C

_{ij}that of clone within family, S

_{k}is the site effect, FAS

_{ik}is the interaction between family and site, CS

_{ijk}is the interaction between clones (within family) and site, B

_{kl}is the block effect within site, and E

_{ijkl}is the random error term. All effects, except S

_{k}, are assumed to be random with expectations 0 and respective variance components. Analyses of variance within each site were based on similar models, but with the site effect and genetic entry by site interactions excluded. The narrow sense heritability in the family trials was calculated for the N × N and E × E families as twice the sum of the female and male variance components divided by the total phenotypic variance that was the sum of all the other variance components, except the block components. The broad sense heritability in the clonal trial was similarly calculated as the sum of the family and clone components divided by the total phenotypic variance. The standard errors of the heritabilities were calculated by the Taylor expansion for variances of ratios [15].

_{ij}= µ + F

_{i}+ M

_{j}+ E

_{ij}

_{ik}= µ + FA

_{i}+ C

_{ikk}

_{ij}and Z

_{ik}are the regression coefficients for family

_{ij}and clone

_{ik}, respectively, and F and Mj are the parental effects in the factorial cross, E

_{ij}is the interaction between the two parents, and FA

_{i}and C

_{ik}are the family and clone within family effects.

## 3. Results

#### 3.1. Mortality and Stem Defects

#### 3.2. Height

#### 3.3. Relationships to Phenology Traits

#### 3.4. Phenotypic Stability Parameters

^{2}values from 0.81 to 0.99. Figure 3a shows the plots of the regression lines and the corresponding values for three of the provenances studied: Åland, Finland (b = 0.69, R

^{2}= 0.86), Harz, Germany (b = 1.27, R

^{2}= 0.87), and Emmaboda, Sweden (b = 0.85, R

^{2}= 0.81). The Åland provenance showed inferior growth at all sites and the lowest values of the regression coefficient. The Harz provenance has a steep regression line with poor growth at the climatic most severe sites and superior performance at the sites with the best growth conditions, particularly at Ølve on the west coast of Norway. When the provenances were grouped in four regions, the Nordic region had the lowest mean regression coefficient of 0.87, the Eastern European had 1.01, the Carpathian Mountains 1.22, and Harz 1.15.

^{2}= 0.72 and ranged between 0.49 and 0.99. The mean regression coefficients were 0.97 and 1.02 in the N × N and E × E family groups, respectively, and with mean R

^{2}values of 0.81 and 0.90.

^{2}= 0.95).

^{2}showed significant variation both among the female (p = 0.02) and male parents (r = 0.002), and with 9% and 21%, respectively, of its variation due to the two types of parents.

^{2}of 0.72 compared to 0.86 in the regressions based on the total site mean). The families contributed very differently to the top 10% in the index, varying from 0 to 15 trees in each trial. One family was not represented at all in any of the indices across the seven trials, and one family was represented by 48 trees. No further analyses were done using this index.

^{2}values equal to 0.47 and 0.32, respectively. This shows that temperature is not the only environmental factor causing differences in performance of the genetic materials at these sites.

^{2}values from 0.46 to 0.99. For the 20 families, mean regression coefficients varied from 0.78 to 1.20. An example of the variation among the clones in one family is presented in Figure 3c. Clone 51 (b = 1.29) had the best height growth at seven sites and was superior at the two most productive sites. When the total variation of the regression coefficients was partitioned into two components, assuming unrelated families, 25% was among families (p = 0.04) and 75% among clones within families. Most likely a substantial part of the large variation among clones is caused by a high experimental error of the clonal means at each site.

^{2}; families with the lowest value for the regression coefficient showed the largest deviation from the regression line.

## 4. Discussion

^{2}) also has a genetic component. Genotypes with a late initiation of shoot elongation generally had the best growth at the productive sites with a steep regression line. Therefore, there are positive relationships between height, Day1, and the regression coefficient, particularly evident in the N × N family group, being more variable in phenology. This shows that the regression coefficient, as a stability parameter, to a large extent is related to these traits.

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 1.**The field test sites in four Nordic countries with the annual temperature sum for mean daily temperature above 5 °C in brackets.

**Figure 2.**Plot of the relationships between the percentage of trees with stem defects (

**a**,

**c**) and tree height (

**b**,

**d**) with the day for shoot growth initiation (Day1) (

**a**,

**b**) and shoot growth cessation (Day2) (

**c**,

**d**) at the family-mean level (site 1–7). The material is grouped in N × N (blue) and E × E families (orange).

**Figure 3.**Estimated regressions lines for the genetic entries’ height increment as a function of the average increment of the trials shown for (

**a**) three selected provenances (sites 1–7), (

**b**) families (sites 1–7), and (

**c**) clones within family 83 (sites 11–18).

**Figure 4.**Plot of regression coefficients estimated for families against the days of shoot growth initiation (Day1) (

**a**) and cessation (Day2) (

**b**), day number after May 1 (sites 1–7). N × N families are blue and the E × E families are orange.

**Table 1.**Locations of field trials with average survival (%), tree height, and proportion of trees with stem defects. Trials 1, 2, 11, and 12 are in Norway; trials 3, 4, 13, and 14 in Sweden; trials 5, 6, 7, 16, 17, and 18 in Finland; and trial 15 is in Denmark. Trials 1 to 7 comprise provenances and families, while trials 11 to 18 comprise clones propagated from 20 of the families. The average values are obtained from measurements nine growing seasons after planting in trials 17 and 18 (*), eleven in trials 1 and 4 (**), and ten in the remaining trials.

Trial and Location | Latitude °N | Longitude °E | Altitude M | Mortality % | Height cm | Stem Defects % |
---|---|---|---|---|---|---|

1 Ølve | 60°00′ | 5°50′ | 50 | 10.2 | 260 ** | 8.9 |

2 Skiptvedt | 59°28′ | 11°11′ | 100 | 24.8 | 224 | 15.5 |

3 Rostorp | 57°47′ | 15°47′ | 165 | 66.0 | 235 | 18.1 |

4 Lappkuliden | 64°16′ | 19°37′ | 190 | 52.8 | 174 ** | 19.3 |

5 Paimio | 60°27′ | 22°44′ | 40 | 4.1 | 279 | 21.7 |

6 Janakkala | 61°00′ | 24°45′ | 130 | 27.6 | 178 | 16.0 |

7 Imatra | 61°10′ | 28°53′ | 80 | 42.9 | 152 | 26.9 |

11 Kaupanger | 61°11′ | 7°05′ | 80 | 8.0 | 183 | 10.0 |

12 Nannestad | 60°19′ | 11°05′ | 200 | 22.1 | 256 | 14.5 |

13 Ribbingelund | 59°19′ | 16°42′ | 50 | 31.9 | 206 | 11.5 |

14 Lappkuliden | 64°1′ | 19°37′ | 190 | 33.2 | 147 | 37.0 |

15 Hørsholm | 55°52′ | 12°04′ | 50 | 14.7 | 377 | 31.9 |

16 Finström | 60°15′ | 19°57′ | 5 | 24.3 | 227 | 27.4 |

17 Paimio | 60°27′ | 22°44′ | 40 | 4.5 | 257 * | 36.1 |

18 Imatra | 61°10′ | 28°53′ | 80 | 28.9 | 126 * | 39.0 |

**Table 2.**The 100 factorial crosses made between 10 Norwegian (N) and 10 Eastern European (E) parents. The N × N and E × E families are indicted as shaded squares. The 20 families that were propagated by rooted cuttings are denoted by X.

Famale Parents | Male Parents | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|

Norwegian (N) | Eastern European (E) | ||||||||||

11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | ||

Norwegian (N) | 1 | X | X | X | X | X | X | X | X | X | X |

2 | X | X | X | X | X | X | X | X | X | X | |

3 | X | X | X | X | X | X | X | X | X | X | |

4 | X | X | X | X | X | X | X | X | X | X | |

5 | X | X | X | X | X | X | X | X | X | X | |

Eastern European (E) | 6 | X | X | X | X | X | X | X | X | X | X |

7 | X | X | X | X | X | X | X | X | X | X | |

8 | X | X | X | X | X | X | X | X | X | X | |

9 | X | X | X | X | X | X | X | X | X | X | |

10 | X | X | X | X | X | X | X | X | X | X |

**Table 3.**Estimates of variance components and narrow sense heritabilities (h

^{2}) for height of 100 families after ten or eleven growing seasons at seven sites (sites 1–7) for each crossing type separately. In parentheses, p-values of variance components and standard error of the heritability.

Source/Cross | N × N | N × E | E × N | E × E |
---|---|---|---|---|

Mean Height (cm) | 205 | 221 | 209 | 219 |

F | 215.5 (0.0002) | 81.3 (0.0002) | 0.0 | 0.0 |

M | 476.8 (<0.0001) | 59.5 (0.007) | 423.3 (<0.0001) | 105.2 (0.001) |

F × M | 38.5 (0.07) | 73.5 (0.0012) | 22.3 (0.20) | 26.0 (0.05) |

F × S | 0.0 | 69.5 (0.0009) | 88.8 (<0.0001) | 66.3 (<0.0001) |

M × S | 71.9 (0.01) | 114.7 (<0.0001) | 117.5 (<0.0001) | 47.7 (0.004) |

F × M × S | 101.2 (0.002) | 2.7 (0.54) | 0.0 | 0.0 |

Error | 5926.4 | 6559.1 | 6066.1 | 5861.8 |

h^{2} | 0.20 (0.15) | 0.03 (0.04) |

**Table 4.**Means and estimates of variance components and the broad sense heritabilities (H

^{2}) for height of clones within families after ten growing seasons at eight sites (sites 11–18). In parentheses, p-values of variance components and standard error of the heritability.

Source | N × N | N × E | E × N | E × E |
---|---|---|---|---|

Mean height (cm) | 169 | 178 | 194 | 187 |

Family | 768.3 (<0.0001) | 651.2 (<0.0001) | 191.8 (0.05) | 269.6 (0.003) |

Family × site | 164.3 (<0.0001) | 84.5 (0.01) | 279.0 (<0.0001) | 200.5 (<0.0001) |

Clone (family) | 503.5 (<0.0001) | 462.3 (<0.0001) | 755.1 (<0.0001) | 373.1 (<0.0001) |

Clone (family) × site | 141.7 (0.01) | 292.9 (<0.0001) | 174.1 (0.04) | 131.6 (0.04) |

Error | 3291.8 | 3451.2 | 4221.4 | 3333.1 |

H^{2} | 0.26 (0.20) | 0.15 (0.11) |

**Table 5.**Estimates of regression coefficients for annual height increment of 100 full-sib families planted at seven sites (sites 1–7). The regression coefficients of the N × N and E × E families are shaded.

Male Female | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | Mean |
---|---|---|---|---|---|---|---|---|---|---|---|

1 | 1.05 | 0.94 | 1.03 | 0.88 | 0.98 | 1.00 | 0.93 | 0.86 | 1.14 | 0.75 | 0.96 |

2 | 1.09 | 1.19 | 0.94 | 0.67 | 1.03 | 1.00 | 1.15 | 1.22 | 0.89 | 0.92 | 1.01 |

3 | 0.75 | 0.82 | 0.91 | 0.85 | 0.82 | 0.74 | 0.86 | 0.98 | 1.03 | 0.79 | 0.86 |

4 | 1.17 | 1.11 | 1.06 | 0.83 | 1.01 | 0.94 | 1.02 | 1.20 | 1.19 | 1.04 | 1.06 |

5 | 0.98 | 1.12 | 0.97 | 1.05 | 0.90 | 0.69 | 1.05 | 1.15 | 0.87 | 1.04 | 0.98 |

6 | 0.93 | 0.77 | 0.99 | 1.01 | 0.79 | 0.81 | 0.64 | 1.19 | 0.97 | 0.96 | 0.91 |

7 | 1.07 | 1.05 | 0.85 | 0.97 | 0.99 | 0.98 | 1.14 | 1.25 | 1.04 | 1.05 | 1.04 |

8 | 1.20 | 1.06 | 0.88 | 1.07 | 0.98 | 0.98 | 1.02 | 1.23 | 1.00 | 1.06 | 1.05 |

9 | 1.44 | 1.36 | 1.01 | 1.20 | 1.01 | 1.08 | 0.99 | 1.19 | 1.11 | 1.03 | 1.14 |

10 | 1.23 | 1.07 | 0.96 | 0.89 | 0.78 | 0.83 | 0.99 | 1.04 | 1.02 | 0.91 | 0.97 |

Mean | 1.09 | 1.05 | 0.96 | 0.94 | 0.93 | 0.90 | 0.98 | 1.13 | 1.02 | 0.96 | 1.00 |

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**MDPI and ACS Style**

Skrøppa, T.; Steffenrem, A. Performance and Phenotypic Stability of Norway Spruce Provenances, Families, and Clones Growing under Diverse Climatic Conditions in Four Nordic Countries. *Forests* **2021**, *12*, 230.
https://doi.org/10.3390/f12020230

**AMA Style**

Skrøppa T, Steffenrem A. Performance and Phenotypic Stability of Norway Spruce Provenances, Families, and Clones Growing under Diverse Climatic Conditions in Four Nordic Countries. *Forests*. 2021; 12(2):230.
https://doi.org/10.3390/f12020230

**Chicago/Turabian Style**

Skrøppa, Tore, and Arne Steffenrem. 2021. "Performance and Phenotypic Stability of Norway Spruce Provenances, Families, and Clones Growing under Diverse Climatic Conditions in Four Nordic Countries" *Forests* 12, no. 2: 230.
https://doi.org/10.3390/f12020230