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Estimation of fertility variation in forest tree populations K.-S. KANG1*, A.D. BILA2, A.M. HARJU3 AND D. LINDGREN4 1
Tree Breeding Division, Korea Forest Research Institute, 44-3 Omokchun, Kwonsun, Suwon, Kyonggi, 441-350, Republic of Korea 2 Department of Forestry Engineering, Eduardo Mondlane University, PO Box 257, Maputo, Mozambique 3 The Finnish Forest Research Institute, Punkaharju Research Station, 58450 Punkaharju, Finland 4 Department of Forest Genetics and Plant Physiology, SLU, SE 901 83, Umeå, Sweden * Corresponding author. E-mail:
[email protected]
Summary Forecasts of the effects of tree breeding and conservation operations require information on fertility variation. In most cases, however, the information does not exist or is highly unreliable. In this paper, published studies on flowering abundance, fruit and seed production were used to estimate and review fertility variation in 99 stands and 36 seed orchards. Fertility variations were described by the coefficient of variation (CV) and the sibling coefficient (Ψ). Both measures express how parents differ in fertility; the former focuses on the variance of fertility among individuals while the later focuses on probabilistic aspects. As expected, fertility varied considerably within and among populations. Only ~15 per cent in both stands and seed orchards indicated small variations in fertility. Fertility variation was higher in stands than in seed orchards. Differences in fertility were usually higher during poor flowering years and in young populations. In seed orchards, fertility differences were slightly larger on the male side than on the female side. For fertility predictions concerning objects that are neither juvenile nor characterized by poor flowering, we suggest, for seed orchards, a CV equal to 100 per cent with Ψ equal to 2 and, for stands, a CV equal to 140 per cent with Ψ equal to 3.
Introduction Forest tree species are usually propagated through sexual reproduction. In managed forests, seed trees left after harvesting assure natural regeneration to produce new forests. In general, seeds used in sowing and for planting are collected from good stands, seed production areas or seed orchards (Zobel and Talbert, 1984; Eldridge et al., 1993). In this review, tree fertility is broadly defined © Institute of Chartered Foresters, 2003
as the relative number of successful gametes of an individual (Gregorius, 1989). For monoecious and hermaphroditic species, fertility can be regarded as the number of offspring fathered or mothered by an individual relative to all the population (Devlin and Ellstrand, 1990). Variation in fertility among forest trees is well documented (e.g. Eriksson et al., 1973; Linhart et al., 1979; Xie and Knowles, 1992; Savolainen et al., 1993; Kang, 2001). Trees vary in reproductive phenology and output (El-Kassaby, 1995; Forestry, Vol. 76, No. 3, 2003
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Matziris, 1998). These variations determine, to a large extent, individual success in contributing genes to the progeny. Random mating, reproductive synchrony and equal gamete contribution are rarely observed, and a few genotypes often produce most seeds in seed orchards and stands (Chaisurisri and El-Kassaby, 1993; Burczyk and Chalupka, 1997; Kang and Lindgren, 1999). Variation in fertility has consequences in both tree breeding and gene conservation programmes. Unequal gamete contribution among trees influences the genetic composition of the offspring by over representing the most fertile genotypes. This leads to the accumulation of relatedness and inbreeding and a reduction in diversity (Gilpin and Soulé, 1986; Xie et al., 1994; Kjær, 1996). Differences in fertility within populations are important elements to consider when managing forest genetic resources; they should be quantified and their impacts in the population should also be evaluated and mitigated to retain genetic diversity. Predictions of conservation and breeding operations (e.g. germplasm collection, establishment and utilization of seed stands and seed orchards) require information on fertility variation. In most cases, however, the information does not exist or cannot be collected due to the young age of the populations concerned. To predict fertility variation, information based on mature stands and seed orchards can be applied. For the present study, we compiled published data on fertility variation within forest tree populations and estimated their magnitudes. Here we focus on differences in fertility, which are important when analysing the consequences of conservation and breeding operations. Factors influencing fertility variation in stands and seed orchards are also discussed.
Materials and methods
can be regarded as samples from a distribution, which can be described by a function with mean µ and variance σ2. A random sample of size N from the function has a mean of M. The fertility of an individual i is expressed as pi N M, where the sum of the pi values adds up to 1. Note that pi can be interpreted as the probability that a gamete originates from individual i. An estimate of the variance of the function can be calculated from a sample as J N2 N K !p i OO 2K N _ NMi K ! p i2 - i = 1 O N O K i =1 K O L P (1) E(σ2) = s2 = _ N - 1i Fertility variation can also be quantitatively described by a coefficient of variation (CV) as follows; J N N N KK N !p i2 - 1OO s L i =1 P CV = = (2) M N -1 Kang and Lindgren (1999) introduced the ‘sibling coefficient Ψ ’ and defined it as
Ψ=N
N
!p i2
(3)
i =1
where N is the number of parents and pi is the fertility of parent i. Note that Ψ has no dimension and expresses how much fertility varies among parents, as it gives the probability that sibs will occur when compared with no differences in fertility. The sibling coefficient Ψ cannot be smaller than 1. If Ψ = 1, all individuals have the same fertility. If Ψ = 2, it means that the probability that two individuals share a parent is double compared with the situation where fertilities are equal across the population. In a random sample, the relationship between Ψ and CV from equations (2) and (3) (cf. Kang and Lindgren, 1998) is _CV i _ N -1i +1 Ψ= N 2
Theoretical framework for quantifying fertility variation Each individual has a fertility value, which describes its ability to transmit genes to the offspring. Fertility can be expressed in absolute or in relative terms. In population studies, the relative values are more relevant. Fertility values
(4)
As formulated here, Ψ is not a descriptor of a function but is related to a parental population of limited size N and its offspring. CV values in this study refer to an imaginary large population (e.g. a large wild forest) and the populations observed
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in the studies are considered to be samples from such populations. Ψ can thus be predicted for a sample of size N using equation (4) with the relevant CV. But, the influence of population size (N) on Ψ will be smaller as the sample size N increases. When fertility information from both sexes is available, the data can also be used for calculating the total fertility variation among parents in a sample population. Total fertility is the average of female and male fertility. If there is no correlation between female and male fertility, the sibling coefficient is calculated according to Kang and Lindgren (1999) as N
2
seed cones were the main traits used in conifers, while fruit and seed production were used in broadleaves. Gender fertility was calculated from data of the respective reproductive trait. In most cases, the number of sampled trees, individual observations, and the mean and standard deviation were available, and thus equation (4) was used to calculate both female and male fertility variation. For seed orchards, the total fertility variation was estimated from equation (5).
Results Stands
f i + mi Ψ = N !f p 2 i =1
= 0.25(Ψf + Ψm – 2)
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N +1 N -1
(5)
where fi and mi are the female and male fertility of parent i, Ψf expresses the female fertility variation and Ψm is the male fertility variation. The sibling coefficient Ψ can be related with effective population size measures, such as status number (Lindgren et al., 1996) and variance effective population size (Kang and Lindgren, 1998). The effective number of parents (Np), as a function of fertility variation, is equal to Np = N/Ψ (Kang and Lindgren, 1999). Therefore, by knowing the magnitude of fertility variation within the population, the number of parents (e.g. the number of clones in a seed orchard or the number of seed trees in a stand) can be chosen to achieve satisfactory diversity. Populations studied Data on flowering abundance, fruit and seed production were used to estimate tree fertility. We assumed that individual fertility could be measured by counting reproductive structures, such as female and male strobili, seed cones, flowers, stamens, pollen, fruits and seeds. Fertility variation was estimated for 99 stands and 36 seed orchards. The population descriptions, species and reproductive traits used to estimate fertility variation are presented in Tables A1 and A2 in the Appendix. The full details with literature references were reported by Bila (2000). The number of female and male strobili and
A summary of fertility variation estimates for stands is shown in Table 1. The number of species and stands of conifer and broadleaved species was unbalanced; conifers accounted for 33 per cent of species and 75 per cent of stands. Female fertility variation was estimated for all stands, while male fertility was only calculated for six stands (i.e. five conifer and one broadleaved species). As expected, individuals varied widely in fertility and there were differences in fertility in most surveyed populations. The overall coefficient of variation ranged from 2 to 636 per cent (mean 141 per cent) and was higher in conifers (146 per cent) than in broadleaves (109 per cent). Sibling coefficients (Ψ) ranged from 1.00 to 41.67, and the overall mean was 4.33. Total fertility variation was higher in conifers (Ψ = 4.66) than in broadleaved species (Ψ = 2.38). The same tendency was observed for female fertility. The overall mean reflected mainly female fertility variation since male fertility observations were few. Flowering abundance had great impact on both CV and Ψ values. CV and Ψ were higher in poor flowering years and lower in good ones. For example, mean Ψ for 31 stands of Norway spruce in good, moderate and poor flowering years (Lindgren and Lindgren, 1976) were 2.14, 5.33 and 12.72 with a corresponding CV of 102, 184 and 350 per cent, respectively (Bila, 2000). There were a few observations with Ψ value close to 1 (Figure 1); only 15 per cent of observations had 1 ≤ Ψ ≤ 1.25, corresponding to a CV of the reproductive trait lower than 50 per cent. Almost half of Ψ estimates were 1.25 ≤ Ψ ≤ 3.20,
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Table 1: Mean, median and range of fertility variation estimates; coefficient of variation (CV) and sibling coefficient (Ψ ) in stands
Ψ
CV (%)
Female Conifers Broadleaved Conifers and broadleaved Male Conifers Broadleaved Conifers and broadleaved Female and male (pooled) Conifers Broadleaved Conifers and broadleaved
No. of species
No. of stands
Mean
Median
Range
Mean
Median
Range
11 20 33
74 25 99
150 109 144
113 92 108
2–638 33–286 2–639
4.79 2.38 4.43
2.18 1.80 2.13
1.0–41.7 1.1–8.80 1.0–41.7
3 1 4
5 1 6
75 113 81
67
27–140
1.73
1.43
1.07–2.9
71
27–140
1.81
1.48
1.07–2.9
11 20 33
74 25 99
146 109 141
109 93 108
2–638 33–286 2–638
4.66 2.38 4.33
2.18 1.82 2.13
1.0–41.7 1.1–8.80 1.0–41.7
35 30
Frequency (%)
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25 20 15 10 5 0 Ψ 1.0-1.25
1.25 - 2.0
2.0 - 3.2
3.2 - 5.0
5.0 - 7.2
7.2 - 9.9
9.9 - 13.1
13.1 - 16.8
> 16.8
CV(%) 0-50
50 - 100
100 - 150
150 - 200
200 - 250
250 - 300
300 - 350
350 - 400
> 400
Figure 1. Observations of Ψ values in stands. The corresponding coefficient of variation (CV, %) interval is also shown on the x-axis. Data from both conifers and broadleaved species.
i.e. a CV ranging from 50 to 150 per cent. Values higher than 3.20 were recorded in ~31 per cent of stands. The distribution of the sibling coefficient Ψ was skewed and a few extreme values had great impact on the average. Differ-
ences between the arithmetic mean and median were relatively higher where the variation was also higher (Table 1). Considering the distribution of Ψ, the overall mean of Ψ was estimated to be about 3 in stands.
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Table 2: Mean, median, range of fertility variation estimates; coefficient of variation (CV) and sibling coefficient (Ψ ) in seed orchards
Ψ
CV (%)
Female Conifers Broadleaved Conifers and broadleaved Male Conifers Broadleaved Conifers and broadleaved Female and male (pooled) Conifers Broadleaved Conifers and broadleaved
No. of species
No. of orchards
Mean
Median
Range
Mean
Median
Range
14 4 18
30 6 36
101 100 101
89 101 91
21–335 68–142 21–335
2.36 2.07 2.33
1.79 2.02 1.79
1.04–12.2 1.44–3.00 1.04–12.2
9 1 10
21 3 24
129 141 130
115 123 115
33–377 85–288 33–377
3.34 3.45 3.44
2.23 2.51 2.26
1.00–15.2 1.72–9.30 1.10–15.2
14 4 18
30 6 36
110 117 111
89 106 94
21–377 68–288 21–377
2.70 2.62 2.69
1.79 2.12 1.86
1.04–15.2 1.44–9.30 1.04–15.2
Seed orchards Fertility variation in seed orchards is presented in Table 2. The number of broadleaved seed orchards included in the survey was limited. There were only six seed orchards, three being of Betula pendula (Bila, 2000). The majority of seed orchards were relatively immature, and the age varied from 3 to 31 years, only two being over 20 years. Female fertility was estimated in all seed orchards, while male fertility variation was estimated in ~70 per cent of seed orchards. In most cases, observations were for only 1 or 2 years. There were three data sets collected over 3 and 5 successive years. In general, CV and Ψ were relatively lower in seed orchards than in stands, except for male fertility variation, which was lower in stands (Tables 1 and 2). As mentioned, the number of male fertility observations was limited in stands compared with seed orchards. Female, male and total fertility varied with ages and years. The amplitude of variation in the female Ψf value was 1.04–12.02, while the male Ψm value ranged from 1.10 to 15.21. Generally, high Ψ value was found in young seed orchards and in poor flowering years (e.g. Lindgren and Lindgren, 1976; Kang and Lindgren, 1999). The overall mean for Ψ was 2.69 and it was 2.70 in conifers and 2.62 in broadleaves. The mean of female fertility variation was 2.33 and that of male fertility was 3.44. Male fertility variation was also higher than
female fertility variation in both conifers and broadleaves. The distributions of the sibling coefficient for both male and female genders are shown in Figure 2. Similar to observations in stands, the distributions of Ψf and Ψm were skewed. The number of observations with lower fertility variation was limited. About 15 per cent and 7 per cent of female and male estimates (Ψf and Ψm) varied between 1 and 1.25, respectively. About 75 per cent of female Ψf values ranged from 1.25 to 3.20, while ~65 per cent of male Ψm values were in the same interval. The overall mean of Ψ was thus determined to be about 2 for mature seed orchards in good or normal flowering years.
Discussion Fertility variation was measured by a sibling coefficient (Ψ) and by the fertility coefficient of variation (CV). Based on our study, we recommend the use of Ψ. The advantage of the Ψ value is that it is related to the probability that gametes coming from the same parent or individuals in the progeny are sibs, while the dispersion parameters (e.g. CV) are not sensitive to this (Kang and Lindgren, 1999). Both of the measures indicate unequal contribution of genotypes to the next generation in forest tree populations as well as in seed orchards.
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Female fertility
40
Male fertility
35
Frequency (%)
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30 25 20 15 10 5 0 Ψ 1.0 - 1.25
1.25 - 2.0
2.0 - 3.2
3.2 - 5.0
5.0 - 7.2
7.2 - 9.9
9.9 - 13.10
13.1 - 16.8
CV(%) 0-50
50 - 100
100 - 150
150 - 200
200 - 250
250 - 300
300 - 350
350 - 400
Figure 2. Observations of Ψf and Ψm values in seed orchards. The corresponding coefficient of variation (CV) interval is also shown on the x-axis. Data from both conifers and broadleaved species.
A cumulative contribution curve has often been used to quantify fertility variation in forest populations (Griffin, 1982; El-Kassaby and Cook, 1994; Adams and Kunze, 1996). Trees are ranked by fertility and the proportion of parents is plotted against accumulative gamete contribution. In most cases, the observed curve deviates largely from the ideal situation in which trees contribute equally to the gamete pool (i.e. Ψ = 1), indicating that a few individuals within the population produce most gametes. For example, it has been reported that 20 per cent of clones produce 80 per cent of seeds in most clonal conifer seed orchards (El-Kassaby, 1995). Many other studies have also reported differences in gamete contribution in natural and managed stands (Xie and Knowles, 1992; Bila and Lindgren, 1998) and seed orchards (Chaisurisi and El-Kassaby, 1993; Savolainen et al., 1993; Burczyk and Chalupka, 1997). The reproductive episode may last for 2 years in most temperate conifers and broadleaves (Sedgley and Griffin, 1989) or some months in tropical broadleaves (Eldridge et al., 1993). It
involves several developmental stages and events, e.g. floral initiation, induction, enhancement and anthesis, in which plant fertility may be affected (Owens, 1995). It has been recognized that the genotype of the individual (Matziris, 1998; Gömöry et al., 2000), its environment (Matthews, 1963), and management practices influence tree fertility both in stands and seed orchards (Zobel and Talbert, 1984; Eriksson et al., 1998). Genotypes having consistent higher or lower fertilities have been observed in several seed orchards (Eriksson et al., 1973; Gömöry et al., 2000; Kang, 2001), natural stands (Linhart et al., 1979) and plantations (Bila and Lindgren, 1998). Xie and Knowles (1992) reported in their study using paternity analysis that <23 per cent of trees in a Norway spruce stand were contributing more than 50 per cent of male gametes to the seed sample. They concluded that floral phenology, pollen production and spatial distribution of male parents were the major factors causing the observed male fertility variation, and that the higher pollen producers were also more successful fathers.
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Environmental manipulation is common practice for seed production both in seed stands and seed orchards (Owens, 1995), which has a great impact on plant reproductive events. In seed orchards, growth is accelerated, the juvenile phase and the onset of flowering are reduced, and flowering is made more regular, while pollination, fertilization, and fruit and seed maturation are easy to monitor and influence (Bonnet-Masimbert and Webber, 1995; Ericksson et al., 1998). The stands and seed orchards included in the present study varied in terms of species, environment, age, developmental stage and management regime. For example, there are natural stands of tropical species such as Brachystegia speciformis, young seed stands of tropical fast-growing Leucaena leucocephala, mature stands of various temperate conifers such as Pinus sylvestris, Picea abies and Pseudotsuga menziesii grown for wood production, and several seed orchards of the same species (Bila, 2000). Those elements are important when analysing fertility variation within and among populations because such factors can affect differently the success of pollination and fertilization, and the production of offspring (i.e. reproductive success). In seed orchards, trees are widely spaced with well-developed crowns and limited height. Thinning is done to eliminate families or clones with low genetic values and those with low flowering and fruiting abilities (Varghese et al., 2000). Topping and pruning are sometimes performed to maintain a short wide crown, encourage the growth of lateral branches and thus increase the number of potential flower, fruit and seed production sites (Ho and Schooley, 1995). Irrigation, fertilizers and plant growth regulators may be used to induce and enhance flowering (Owens, 1995; Setiawati and Sweet, 1995). The effects of these practices are likely to make trees more similar in fertility, which corresponds well with the present results from seed orchards. It should be emphasized that fertility data for many seed orchards are based on clonal averages and are thus less variable compared with observations on individual trees in natural and managed stands. The management of natural forests or wood production stands is far less intensive compared with the seed orchards. In general, the initial density is higher to promote height growth, good form, natural pruning, and
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small dense crowns. Thinning is done mainly to control competition and to concentrate the site growth potential to a few individuals, the final crop (Zobel et al., 1988). Flowering is generally not considered when selecting trees for the main crop. As emphasized by Zobel and Talbert (1984), favourable conditions for vegetative growth may not coincide with the most productive in terms of flowering, fruiting and seed production. Therefore, lower fertility variation could be expected in seed orchards compared with seed stands. The tree age, size, growth and location have been recognized as affecting fertility in plants (Sedgley and Griffin, 1989; Crawley, 1997). In the northern hemisphere, seed orchards are in general located at lower latitudes or altitudes where conditions are considered more favourable for flowering and seed production (Zobel et al., 1988). Flower, fruit and seed set in young plants are sparse and sporadic, but increase with age and size (Matthews, 1963). Flowering and fruit production, e.g. in Tectona grandis, is usually confined to sunny crowns of the dominant and co-dominant trees (Hedegart, 1976), indicating that best competitors are also the most fertile trees in the population (Bila et al., 1999). If pollination is not a limiting factor, seed production is roughly a function of plant size in most tree species (Crawley, 1997). Reproductive success includes many components. Besides the flowering ability, the ability to set seed and the ability of progeny to survive and grow to a dominant tree are other important factors. Trees may compensate for less flowering with more growth, and these factors may compensate each other for reproductive success over the life cycle. To discuss evolutionary patterns, it is hardly relevant to limit the discussion to fertility but fertility is an important component. Early flowering and a poor flowering year are probably seldom of evolutionary significance, but might be more significant in breeding and for conservation. This review focuses on fertility variations, which are of interest for evaluating the ‘effective population size’ of seed crops and forest tree breeding operations. Evaluating the consequences of breeding operations, e.g. seed orchards and seed stands, requires predictions of fertility variation. Data cannot be collected for populations that are not established
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or not yet mature, and usually little information exists for similar populations. This review may be helpful in these cases. It is suggested that, for seed orchards, a CV value equal to 100 per cent with a Ψ value equal to 2 and, for stands, a CV value equal to 140 per cent with a Ψ value equal to 3 could be applied as typical values in the absence of other information. Generally speaking, therefore, for a given population size, the effective number of parents (Kang and Lindgren, 1999) is ~150 per cent larger in seed orchards than in stands. The values suggested are partly chosen as they are even and slightly above the mean, and can thus be regarded as a little conservative, which we think is desirable. For individual cases, they can be modified based on observations in the population themselves or on the most relevant information reported in this review. Acknowledgements Most of the work was done while Kyu-Suk Kang, Adolfo Bila and Anni Harju visited the Department of Forest Genetics and Plant Physiology, SLU-Umeå, Sweden. The Forest Research Institute of Korea, the Eduardo Mondlane University of Mozambique, the Swedish Research Council for Forestry and Agriculture, the Kempe Foundation of Sweden and the Research Council for Biosciences and Environment in the Academy of Finland financed this study and they are all gratefully acknowledged. The authors thank Dr Erik D. Kjær for his valuable discussion.
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seed crops in seed orchards. Ph.D. thesis. Swedish University of Agricultural Sciences, Umeå, Sweden. Acta Universitatis Agriculturae Sueciae, Silvestria 187, 75 pp. Kang, K.S. and Lindgren, D. 1998 Fertility variation and its effect on the relatedness of seeds in Pinus densiflora, Pinus thunbergii and Pinus koraiensis clonal seed orchards. Silvae Genet. 47, 196–201. Kang, K.S. and Lindgren, D. 1999 Fertility variation among clones of Korean pine (Pinus koraiensis S. et Z.) and its implications on seed orchard management. For. Genet. 6, 191–200. Kjær, E.D. 1996 Estimation of effective population number in a Picea abies (Karst) seed orchard based on flower assessment. Scand. J. For. Res. 11, 111–121. Lindgren, D. and Lindgren, K. 1976 The effective population size of Norway spruce. In Proceedings from the Conference on Forest Genetic Resources. The Department of Forest Genetics, Swedish College of Forestry, Stockholm, pp. 125–135. Lindgren, D., Gea, L. and Jefferson, P. 1996 Loss of genetic diversity monitored by status number. Silvae Genet. 45, 52–59. Linhart, Y.B., Mitton, J.B., Bowman, D.M., Sturgeon, K.B. and Hamirick, J.L. 1979 Genetic aspects of fertility differentials in ponderosa pine. Genet. Res. Camb. 33, 237–242. Matthews, J.D. 1963 Factors affecting the production of seed by forest trees. For. Abst. 24, 1–11. Matziris, D. 1998 Genetic variation in cone and seed
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characteristics in a clonal seed orchard of Aleppo pine grown in Greece. Silvae Genet. 47, 37–41. Owens, J.N. 1995 Constrains to seed production: temperate and tropical trees. Tree Physiol. 15, 477–484. Savolainen, O., Kärkkäinen, K., Harju, A., Nikkanen, T. and Rusanen, M. 1993 Fertility variation in Pinus sylvestris: a test of sexual allocation theory. Am. J. Bot. 80, 1016–1020. Sedgley, M. and Griffin, A.R. 1989 Sexual Reproduction of Tree Crops. Academic Press, London. Setiawati, Y.G.B. and Sweet, G.B. 1995 Increase of seed yield and physical quality in a Pinus radiata controlpollinated meadow seed orchard. Silvae Genet. 45, 91–96. Varghese, M., Nicodemus, A., Nagarajan, B., Siddappa, K.R.S., Bennet, S.S.R. and Subramanian, K. 2000 Seedling Seed Orchards for Breeding Tropical Trees. Scroll, Coimbatore, India. Xie, C.Y. and Knowles, P. 1992 Male fertility variation in an open-pollinated plantation of Norway spruce (Picea abies). Can. J. For. Res. 22, 1463–1468. Xie, C.Y., Woods, J. and Stoehr, M. 1994 Effects of seed orchard inputs on estimating effective population size of seedlots – a computer simulation. Silvae Genet. 43, 145–154. Zobel, B. and Talbert, J. 1984 Applied Forest Tree Improvement. John Wiley & Sons, NY. Zobel, B., Wyk, G. van and Ståhl, P. 1988 Exotic Forestry. John Wiley & Sons, New York.
Received 2 November 2000
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Appendix Table A1: Stand description (species, location), reproductive trait used to estimate fertility variation (CV and Ψ ) and reference Stand description Observed Age trees (N) (years)
CV Trait (%)*
Ψ*
Species
Location
Conifers Picea engelmannii c, d, g c, d, g
USA Niwot Ridge Niwot Ridge
13 13
138 138
FS1 MS1
24 28 Total
1.05 1.07 1.03
P. engelmannii c, d, h c, d, h
USA Niwot Ridge Niwot Ridge
19 19
245 245
FS1 MS1
18 27 Total
1.03 1.07 1.03
Picea lasiocarpa c, d, g c, d, g
USA Niwot Ridge Niwot Ridge
20 20
127 127
FS1 MS1
7 63 Total
1.00 1.38 1.10
P. lasiocarpa c, d, h c, d, h
USA Niwot Ridge Niwot Ridge
20 20
154 154
FS1 MS1
5 71 Total
1.00 1.48 1.13
Picea abies b, e c, e c, e c, e c, e c, e c, e c, e P. abies c, e c, e c, e c, e c, e c, e c, e c, e c, e c, e c, e c, e c, e c, e c, e c, e c, e c, e c, e c, e
Finland Vesijako Vesijako Vesijako Vesijako Vesijako Ruotsinkylä Ruotsinkylä Ruotsinkylä Sweden Simlångsdalen Osby Rörsbo Ljungby Hemse Sandbäckshult Buttle Bollebygd Målilla Fagered Allgunnen Vimmerby Segerstad Nävelsjö Ulricehamn Prästkulla Alvhem Svarteborg Åtvidaberg Remningstorp
525 437 270 109 207 428 113 66
40 80 100 100 110 90 110 110
SC1 SC1 SC1 SC1 SC1 SC1 SC1 SC1
54 34 10 29 71 59 76 28
1.29 1.11 1.01 1.08 1.49 1.35 1.57 1.08
CC1 CC1 CC1 CC1 CC1 CC1 CC1 CC1 CC1 CC1 CC1 CC1 CC1 CC1 CC1 CC1 CC1 CC1 CC1 CC1
214 153 91 280 109 117 220 266 150 126 123 129 140 103 211 308 199 204 198 172
Reference
Shea (1987)
Shea (1987)
Shea (1987)
Shea (1987)
Heikinheimo (1932)
27 39 27 43 28 37 31 24 22 37 40 23 32 38 46 31 28 36 39 25
Lindgren and Lindgren 11.24 (1976) 3.82 (estimates based on Nr) 1.94 11.72 2.19 2.74 7.20 10.00 3.28 2.79 2.53 3.11 3.43 2.10 6.47 13.18 5.51 5.85 6.90 4.64
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Table A1: Continued Stand description Species c, e c, e c, e c, e c, e c, e c, e c, e c, e P. abies c, e c, e j l i Abies balsam c, e P. mariana c, e Larix lariciana c, e Pinus sylvestris e e P. sylvestris c, d, l c, d, I P. sylvestris b, e b, e b, e b, e c, e c, e c, e c, e c, e c, e c, e Picea abies c, e Pinus resinosa e e Pinus densiflora e e e P. caribaea var. hondurensis b, f
Location
Observed Age trees (N) (years)
CV Trait (%)*
Ψ*
53 35 19 17 39 32 18 32 37
CC1 CC1 CC1 CC1 CC CC CC CC CC
187 288 160 129 208 161 146 277 211
27 43
CC1 CC1
195 301 184 102 350
Canada Long Harbour
80
CC1
47
Long Harbour
82
CC1
57
1.32
Long Harbour Finland
28
CC1
8
1.01
25 25
SC2 PP2
148 132
3.10 2.68
44 40
SC1 SC1
16 200
1.02 4.90
SC1 SC1 SC1 SC1 SC1 SC1 SC1 SC1 SC1 SC1 SC1
47 98 77 4 94 41 65 58 23 106 113
1.22 1.95 1.59 1.00 1.88 1.17 1.42 1.58 1.04 2.11 2.27
(FS) CC1 138
2.89
Snavlunda Malexander Västerås Röskär Kårsta Styckebruk Åmål Strängstorp Arvika Sweden Skinnskatteberg Filipstad
Finland Ylläs Ylläs Finland Vesijako Ruotsinkylä Ruotsinkylä Punkaharju Vesijako Kivalo Pohjankangas Ruotsinkylä Ruotsinkylä Ruotsinkylä Vesijako Finland
Reference
4.79 13.28 4.29 3.09 8.05 4.75 3.35 12.71 5.84 Lindgren and Lindgren 5.58 (1976) 15.83 5.33 2.14 12.72 Sidhu and Staniforth 1.22 (1986)
Kärkkäinen (1990)
Harju et al. (1996)
Heikinheimo (1932) 299 167 76 52 292 140 104 174 5 394 95
50 55 55 75 80 80 90 95 95 100 110
Malmivaara (1971) 99
Stiell (1988) 28 28 Korea Kwanak Dobong Hongneung Nigeria Ibadan
18 32
FS1 FS1
74 60
1.53 1.35
SC3 SC3 SC3
99 107 61
1.94 2.07 1.36
CC1
125
Okoro and Okali 2.42 (1987)
Kang (1999) 21 16 31 11
17
Continued overleaf
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Table A1: Continued Stand description Species a, f a, f Pseudotsuga menziesii f Broadleaf Acacia farnesiana c, d Bauhinia ungulata c, d Cochlospermum vitifolium c, d Grilicidia sepium c, d Spondias purpurea c, d Crescentia alata c, d Milletia stuhlmannii c, d Brachystegia boemii c, d Brachystegia spiciformis c, d Gliricidia sepium a, f Leucaena diversifolia a, f Leucaena pallida a, f Leucaena pallida a, f Leucaena trichandra a, f Leucaena trichandra a, f Leucaena leucocephala a, f Milletia stuhlmannii c, f Tectona grandis c, f
Hybantus prunifolius c, d Turnera panamensis c, d Rinorea sylvatica c, d
Location
Observed Age trees (N) (years)
Ngow 11 Ikom 12 Canada British Columbia 621
CV Trait (%)*
Ψ*
11 5
CC1 CC1
75 67
1.51 1.41
18–24
CC1
193
5.12
Reference
El-Kassaby et al. (1989)
Costa Rica Canas
10
FC2
112
2.13
Rockwood (1973)
Canas
10
FC2
72
1.47
Canas Costa Rica Canas
10
FC2
110
2.09
10
FC2
129
2.50
Canas
9
FC2
204
4.70
Canas Mozambique Inhassoro
8
FC2
86
1.65
50
SC1
71
1.49
Inhassoro
50
SC1
93
1.85
Inhassoro Nigeria Ibadan Kenia Machako
50
SC1
117
2.34
20
2
SC2
93
1.82
20
2
SC2
91
1.79
Machako
20
2
SC2
207
5.07
Muguga
20
2
SC2
286
8.77
Machako
20
2
SC2
33
1.10
Muguga Mozambique Maputo
20
2
SC2
46
1.20
45
0.5
SC1
129
2.63
Maputo Mocambique Namaacha
100
60
SC1
74
1.54
154 154
65 65
FC1 ST1
113 113 Total
2.27 2.28 1.65
Rockwood (1973)
Bila and Lindgren (1998)
Sumberg (1983) Were et al. (1998)
Bila and Lindgren (1998)
Bila et al. (1998)
Panama Barro Colorado
20
SC1
91
1.78
Augspurger (1983)
Barro Colorado
20
SC1
76
1.55
Barro Colorado
20
SC1
85
1.69
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Table A1: Continued Stand description Species Psychotria horizontalis c, d Erythrina costaricensis c, d Pentagonia macrophylla c, d
Location
Observed Age trees (N) (years)
CV Trait (%)*
Ψ*
Barro Colorado
20
SC1
128
2.56
Barro Colorado
20
SC1
83
1.65
Barro Colorado
20
SC1
78
1.57
Reference
a, juvenile; b, intermediate; c, mature; d, natural stand; e, managed stand; f, plantation; g, wet site; h, dry site; i, poor flowering year; j, moderate flowering year; l, good flowering year. CC, cone crop; FC, fruit crop; FS, female strobili; MS, male strobili; SC, seed crop; PP, pollen production; ST, stamens. 1 Number per tree; N , relative effective population size; 2 gram per tree; 3 number per cone. r * Averaged values. Table A2: Seed orchard description (species, location), reproductive trait used to estimate fertility variation (CV and Ψ ) and reference Seed orchard description Species Conifers Picea abies a
P. abies
Location
Observed Age genotype (years)
Sweden Röskär Stockolm Sweden Jung
CV Trait (%)*
Ψ*
Reference
Eriksson et al. (1973) 20
11
FS5 MS5 Total
99 115
1.93 2.26 1.58
40
6–13
FS5 MS5 Total
197 156
5.98 2.62 2.69
100
10
Total
65
1.42
24 24 24
28 29 31
Total Total Total
94 85 61
1.85 1.69 1.36
P. abies a
Denmark
P. abies a
Denmark
Picea glauca a
Canada Ontario
12
12
SC9 MS9 Total
49 151
1.24 3.29 1.69
P. glauca a
Canada Ontario
33
11–12
FS9 MS9 Total
125 150
2.68 3.24 2.10
P. glauca
Canada Central Plateau
15
9
CC3 PC3
78 115
1.57 2.23 1.46
Lindgren and Lindgren (1976) (estimates based on Nr) Kjaer and Wellendorf (1997) (estimates based on Ns) Kjær (1996) (estimates based on Ne(i)) Denti and Schoen (1988)
Schoen et al. (1986)
Ross (1992)
Continued overleaf
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Table A2: Continued Seed orchard description Species
P. glauca
Location
Canada Bulkley Valley
Observed Age genotype (years) 9
CC3 PC3
156 168
3.27 3.63 2.26
15
8
CC3 PC3
92 78
15
8
CC3 PC3
136 117
1.79 1.57 1.35 2.73 2.28 1.77
12
6 9
CC9 CC9
64 45
17–19
CC1
88
13
FS9 MS9 Total
57 120
Picea sitchensis
Canada British Columbia 22 Canada Ontario 12
Pinus contorta a
Sweden Bogrundet Sundsvall
40
13
FS3 PP3 Total
56 89
P. contorta a
Sweden Bogrundet Sundsvall
20
12–19
FS3 MS3 Total
100 53
Pinus densiflora b
Korea Anmyun
99
20
FS1 MS1 Total
94 64
Pinus thunbergii b
Korea Anmyun
60
18
FS1 MS1 Total
36 57
Pinus koraiensis a
Korea Gomae
180
8–12
FS1 MS1 Total
118 321
Pinus nigra a
Spain Guadalajara Guadalajara Australia Gippsland
30 228
3–7 3–7
FS9 FS9
101 190
30
8
SC2 CPA Total
77 50
41
13–15
CC5
94
32
18
CC1
21
Pinus sylvestris P. sylvestris b
USA Nebraska Poland Gniewkowo
Reference
Ross (1992)
USA Wisconsin
Pinus radiata b
Ψ*
15
P. glauca Juvenile
Picea mariana a
CV Trait (%)*
Nienstaedt and Jeffers 1.41 (1970) 1.20 Chaisurisri and 1.83 El-kassaby (1993) O’Reilly et al. (1982) 1.30 2.32 1.44 Yazdani and Fries 1.31 (1989) 1.79 1.28 Fries (1994) 2.15 1.30 1.54 Kang and Lindgren 1.87 (1998) 1.41 1.32 Kang and Lindgren 1.13 (1998) 1.32 1.11 Kang and Lindgren 2.42 (1999) 11.54 4.01 Climent et al. (1997) 2.05 4.78 Griffin (1982) 1.59 1.25 1.22 Boes et al. (1991) 1.90 Burczyk and Chalupka 1.04 (1997)
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Table A2: Continued Seed orchard description Species
Location
P. sylvestris a
Sweden Långtora Enköping
P. sylvestris c
Finland Viitaselkä
P. sylvestris b
Finland
P. sylvestris c
P. sylvestris c
Observed Age genotype (years)
CV Trait (%)*
Ψ*
PP2 Total
56
1.32 1.09 Jonsson et al. (1976)
36
12
FS1 MS1 Total
93 72
1.87 1.53 1.36
24
31
SC PP2 Total
43 53
1.17 1.27 1.11
25 25
21–22 21–22
PP2 PP2
64 116
1.39 2.29
Finland Viitaselkä
25
31
CC7 PP6 Total
76 57
1.58 1.32 1.24
Finland Vihelminmäki
28
27
CC7 PP6 Total
103 136
2.06 2.85 1.75
14
7
CC5
106
2.12
18
10–12
FS9
114
2.33
Pinus nigra b Pinus halepensis a P. halepensis a Pseudotsuga menziesii a P. menziesii
52
11–13
CC1
65
1.44
55
4–10
FS1
52
1.28
60
8–9
FSE1
34
1.12
21
13
SC1
27
1.07
FSE1
P. menziesii
55
1.29
Broadleaf Acacia mangium a Acacia auriculiformis a Betula pendula
B. pendula
Kärikkäinen and Savolainen (1992)
Koski (1981)
Pinus taeda P. taeda
Reference
Muona and Harju (1989) Savolainen et al. (1993)
Muona and Harju (1989) Savolainen et al. (1993)
Bergman (1968) USA South Mississippi Greece Peloponnesos Greece Amphilochia Greece Amphilochia USA Washington Canada Saanichton Canada Pacific Forest
Indonesia Sabah
Schmidtling (1983) Matziris (1993) Matziris (1997) Matziris (1998)
19 35
19
FSE1
104
2.05
24
1
FC9
80
1.61
Erickson and Adams (1989) El-Kassaby and Thomson (1996) El-Kassaby and Cook (1994)
Griffin et al. (1992)
Sabah Finland Punkaharju
25
1
FC9
131
2.65
10
3–4
114 207
Punkaharju
10
3–4
SCK5 MCK5 Total SCK5 MCK5 Total
2.32 5.94 2.74 2.29 2.19 1.69
108 107
Viherä-Aarnio and Ryynänen (1995)
Continued overleaf
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Table A2: Continued Seed orchard description Species
Location
Observed Age genotype (years)
CV Trait (%)*
Ψ*
SCK5 90 MCK5 110 Total
1.84 2.22 1.57
Reference
B. pendula
Tectona grandis b
Punkaharju
10
3–4
India Dehra Dun
20
9
Rawat et al. (1992) FC2
68
1.44
a, Juvenile; b, intermediate; c, mature; d, indoor seed orchard; e, seedling; f, micropropagated plant; g, homoplastic graft; h, heteroplastic graft; i, poor flowering year; j, moderate flowering year; l, good flowering year. CC, Cone crop; CPA, clone pollen abundance; FC, fruit crop; FS, female strobili; MS, male strobili; SC, seed crop; FSE, filled seed; PC, pollen cone; PP, pollen production; SCK, seed caktins; MCK, male caktins; Nr, relative status number; Ns, status number; Ne(i), inbreeding effective number. 1 Number per clone; 2 gram per clone; 3 number per graft; 4 gram per graft; 5 number per tree; 6 gram per tree; 7 litre per tree; 8 number per family; 9 number per ramet. * Averaged values.
