Genetic variation and parental performance under inbreeding for growth in Eucalyptus globulus

Silva, João Costa e; Hardner, Craig; Potts, Brad M.

doi:10.1051/forest/2010019

Cited by 29 publications

(20 citation statements)

References 28 publications

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“…Self-families of E. globulus have been shown to differ in ID (Costa e Silva et al, 2010b). In the present study, selffamilies differed significantly in their diameter growth at both sites and their performance was highly stable across sites (as indicated by high across-site family correlation estimates).…”

Section: Discussionmentioning

confidence: 45%

“…Total genetic variance may increase when dominance effects that arise under inbreeding are important (Kelly, 1999;Moorad and Wade, 2005), hence augmenting variation both among and within families after inbreeding. Plant studies have indicated that significant ID was generally accompanied by an important contribution to genetic variance of dominance effects that arise with inbreeding, such as the variance due to homozygous dominance deviations (Shaw et al, 1998;Kelly and Arathi, 2003;Costa e Silva et al, 2010b). In addition, when studying the effects of inbreeding on the variation due to rare recessive alleles, Robertson (1952) observed that the additive component of the genetic variance can be enhanced within inbred lines after inbreeding, increasing to a maximum value when f is close to 50% (and then declining to zero when inbreeding is complete).…”

Section: Discussionmentioning

confidence: 99%

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The effects of age and environment on the expression of inbreeding depression in Eucalyptus globulus

Silva¹,

Hardner

Tilyard

et al. 2011

Heredity

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Inbreeding adversely affects fitness traits in many plant and animal species, and the magnitude, stability and genetic basis of inbreeding depression (ID) will have short-and longterm evolutionary consequences. The effects of four degrees of inbreeding (selfing, f ¼ 50%; full-and half-sib matings, f ¼ 25 and 12.5%; and unrelated outcrosses, f ¼ 0%) on survival and growth of an island population of Eucalyptus globulus were studied at two sites for over 14 years. For selfs, ID in survival increased over time, reaching a maximum of 49% by age 14 years. However, their inbreeding depression for stem diameter remained relatively stable with age, and ranged from 28 to 36% across years and sites. ID for survival was markedly greater on the more productive site, possibly due to greater and earlier onset of inter-tree competition, but was similar on both sites for the diameter of survivors. The deleterious trait response to increasing inbreeding coefficients was linear for survival and diameter. Nonsignificant quadratic effects suggested that epistasis did not contribute considerably to the observed ID at the population level. Among-and within-family coefficients of variation for diameter increased with inbreeding degree, and the variance among the outcrossed families was significant only on the more productive site. The performance of self-families for diameter was highly stable between sites. This suggests that, for species with mixed mating systems, environmentally stable inbreeding effects in open-pollinated progenies may tend to mask the additive genotype-by-environment interaction for fitness traits and the adaptive response to the environment.

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Section: Discussionmentioning

confidence: 45%

Section: Discussionmentioning

confidence: 99%

The effects of age and environment on the expression of inbreeding depression in Eucalyptus globulus

Silva¹,

Hardner

Tilyard

et al. 2011

Heredity

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“…Thus, seeds for conservation genetics, progeny tests and reforestation must be collected from a large number of seed-trees to retain an evolutionarily effective population size (for example, 150). Our results also indicate that the estimation of genetic parameters in a progeny test must consider deviation from random mating to obtain accurate estimates of heritability and genetic gains of quantitative traits, as related by Costa e Silva et al (2010) in Eucalyptus globulus.…”

Section: Correlated Paternity Among and Within Fruits And Effective Nmentioning

confidence: 64%

Mating system parameters at hierarchical levels of fruits, individuals and populations in the Brazilian insect-pollinated tropical tree, Tabebuia roseo-alba (Bignoniaceae)

et al. 2011

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For many tree species, mating system analyses have indicated potential variations in the selfing rate and paternity correlation among fruits within individuals, among individuals within populations, among populations, and from one flowering event to another. In this study, we used eight microsatellite markers to investigate mating systems at two hierarchical levels (fruits within individuals and individuals within populations) for the insect pollinated Neotropical tree Tabebuia roseo-alba. We found that T. roseo-alba has a mixed mating system with predominantly outcrossed mating. The outcrossing rates at the population level were similar across two T. roseo-alba populations; however, the rates varied considerably among individuals within populations. The correlated paternity results at different hierarchical levels showed that there is a high probability of shared paternal parentage when comparing seeds within fruits and among fruits within plants and full-sibs occur in much higher proportion within fruits than among fruits. Significant levels of fixation index were found in both populations and biparental inbreeding is believed to be the main cause of the observed inbreeding. The number of pollen donors contributing to mating was low. Furthermore, open-pollinated seeds varied according to relatedness, including half-sibs, full-sibs, self-sibs and self-half-sibs. In both populations, the effective population size within a family (seed-tree and its offspring) was lower than expected for panmictic populations. Thus, seeds for ex situ conservation genetics, progeny tests and reforestation must be collected from a large number of seed-trees to guarantee an adequate effective population in the sample.

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“…and Eucalyptus nitens (Deane & Maiden) Maiden, comparisons of genetic parameters estimated from OP and CC progenies of the same genetic origin have been published (e.g. Costa e Silva et al, 2010;Griffin and Cotterill, 1987;Hodge et al, 1996;Jordan et al, 1999). In contrast to observations made on spruces and pines, additive genetic variances estimated from Eucalypt OP progenies were frequently four times as large as additive genetic variances estimated from progenies generated by controlled crosses given that the classical assumption of true half-sibs was made.…”

Section: Genetic Correlations Between Op and CC Trialsmentioning

confidence: 99%

“…Studies based on this type of comparison between the methods of progeny generation have hitherto been few in number, and most have used Eucalyptus spp (e.g. Costa e Silva et al, 2010;Griffin and Cotterill, 1987;Hodge et al, 1996). To our knowledge there are no published studies on conifers comparing genetic parameters estimated from OP and CC progenies of the same parents.…”

Section: Introductionmentioning

confidence: 99%

Genetic information from progeny trials: a comparison between progenies generated by open pollination and by controlled crosses

Hallingbäck

Jansson

2013

Tree Genetics & Genomes

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When conifer progenies generated by open pollination are assessed in field tests, it is usually assumed that all progenies of the same mother are true half-sibs. This assumption may be invalid, leading to overestimation of additive genetic variation and heritability and to biased breeding values. From one Scots pine (Pinus sylvestris) and one Norway spruce (Picea abies) seed orchard, containing 28 and 36 parent clones respectively, progenies generated by open pollination (OP) and by controlled crosses (CC) were planted in adjacent trials at two to three sites in southern Sweden. The tree height and diameter at breast height were measured and genetic parameters based on these traits were estimated for OP and CC progenies separately, in order to enable comparisons. Narrow sense heritability estimates for Scots pine and Norway spruce OP progenies (in the ranges 0.04-0.13 and 0.15-0.38, respectively) did not differ significantly from CC estimates (0.07-0.12 and 0.23-0.30), suggesting that OP-based heritability values were not overestimated to any great extent. Similarly, genetic correlations between OP and CC progenies were in the ranges 0.87-0.88 and 0.74-0.77 for Scots pine and Norway spruce, respectively, being significantly lower than unity only in the case of Norway spruce. OP-based breeding values for both species should therefore correspond well with those predicted from CC progenies, albeit not perfectly for Norway spruce. In conclusion, the assumption of true half-sibs for OP progenies was not violated to the extent that genetic parameter estimates or breeding value predictions were seriously biased.

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Genetic variation and parental performance under inbreeding for growth in Eucalyptus globulus

Cited by 29 publications

References 28 publications

The effects of age and environment on the expression of inbreeding depression in Eucalyptus globulus

The effects of age and environment on the expression of inbreeding depression in Eucalyptus globulus

Mating system parameters at hierarchical levels of fruits, individuals and populations in the Brazilian insect-pollinated tropical tree, Tabebuia roseo-alba (Bignoniaceae)

Genetic information from progeny trials: a comparison between progenies generated by open pollination and by controlled crosses

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