Group coancestry-controlled selection in a Pinus sylvestris L. breeding program

Andersson, Erik; Rodriguez, Leopoldo Sanchez; Andersson, Bengt

doi:10.1007/s001220051210

Cited by 5 publications

(3 citation statements)

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“…Many studies on tree breeding theory considered the effects of selection on gain estimates and genetic diversity in the form of an effective population size for breeding and production populations (Wei andLindgren 1995, 1996;Lindgren and Mullin 1997;Andersson et al 1999;Kang 2001;Olsson et al 2001, Lindgren andPrescher 2005). Although these studies stress the trade-offs between diversity and genetic gain that follow selection decisions, they do not consider explicitly the biological cost of inbreeding in terms of the merchantable volume production at rotation age.…”

Section: Introductionmentioning

confidence: 99%

Gain and diversity in advanced generation coastal Douglas-fir selections for seed production populations

Stoehr¹,

Yanchuk²,

Xie³

et al. 2007

Tree Genetics & Genomes

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Sublines are used in the third-generation breeding and testing of coastal Douglas-fir in British Columbia, with the original intent of selecting only one genotype per subline for production populations (e.g., seed orchards) to eliminate relatedness among parents (therein called "1/ SL"). We evaluated three additional selection scenarios that did not consider the subline structure. One of the scenarios strictly selected on the basis of the highest breeding values of the trees ("TOP"); another scenario used the TOP selections, but assigned the number of ramets per selection proportionally to the selection breeding value ("LIND"); lastly, a simulated annealing technique was applied to maximize gain under explicit constraints on coancestry ("OPTS"). All three alternative selection scenarios resulted in some relatedness and coancestry among selections, but the last two provided increases in average breeding values compared to those obtained by the 1/SL scenario. Effective population sizes (and consequently inbreeding coefficients) varied among the three selection scenarios. Effects of the various selections on merchantable volume at rotation age were determined using a linear regression model based on an individual tree model (TASS), which was first run to determine the relationship between merchantable volume and inbreeding (f). LIND and TOP selections yielded the highest breeding values but, due to the increased coancestry among selections, paid a penalty in the merchantable volume determination. OPTS maximized merchantable volume at rotation age 60 after including more than 13 selections with an increase of around 3% over that obtained by the 1/SL selection scenario, with an associated increase in Ne of 50%. Other implications of the three alternative selection scenarios are discussed.

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Section: Introductionmentioning

confidence: 99%

Gain and diversity in advanced generation coastal Douglas-fir selections for seed production populations

Stoehr¹,

Yanchuk²,

Xie³

et al. 2007

Tree Genetics & Genomes

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“…The expected gains may be estimated by BLUP breeding value (BV), but usually the selection of candidate trees involves some constraints on relatedness among individual genotypes. One criterion to cope with the balance between gain and inbreeding is based on optimal effective population size for breeding and production populations (Weir and Lindgren 1996;Lindgren and Mullin 1997;Anderson et al 1999;Olsson et al 2001). Brisbane and Gibson (1995) proposed a method that maximizes the genetic gain for a given level of inbreeding based on group merit selection (GMS), which incorporates breeding value and coancestry into a single selection criterion that penalizes the increase of average coancestry in the selected group GMS.…”

Section: Introductionmentioning

confidence: 99%

Improving initial trials in tree breeding using kinship and breeding values estimated in the wild: the case of Prosopis alba in Argentina

et al. 2015

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Most Argentinean forests have been lost by over exploitation and expansion of agricultural areas. The National breeding program for the native species Prosopis alba is still in its initial phase with only a few progeny trials installed from material collected in the wild and the first genetic studies are underway. Breeding value (BV) estimates based on pedigree data from a progeny trial were first compared to those derived by using microsatellite based kinship estimates to confirm the potential accuracy of g-best linear unbiased predictions (G-BLUP) when pedigree information is lacking. Afterwards, the possible genetic effects of alternative selection strategies to collect improved seeds from a wild population were evaluated. To achieve this goal the relationship among average genetic gain (predicted by G-BLUP), inbreeding and sampling size of the collected materials were weighed in a wild population consisting of trees of similar ages. The results obtained suggest that kinship estimates based on molecular data and breeding value predictions BV used for the selection of elite trees in wild populations may contribute to improve the genetic properties of the founder population. Controlling kinship allows reducing sampling size from 20 to 10 individuals per origin with no significant increase of inbreeding or loss of genetic gain. For a selected group of only ten top individuals per origin, the replacement of two strongly reduces the average group coancestry with minimal gain loss. Simultaneous selection for two traits by selection index might produce a gain of near 6 % in height and 2 % in diameter. The use of molecular marker information may contribute to reduce the time needed in a P. alba improvement program.

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“…We call a spacetime satisfying these assumptions a CMC cosmological vacuum spacetime. For surveys of prior work on such spacetimes, see [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Asymptotic behaviour of future-complete cosmological spacetimes

Anderson¹

2003

Class. Quantum Grav.

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This work discusses the apriori possible asymptotic behavior to the future, for (vacuum) space-times which are geodesically complete to the future, and which admit a foliation by constant mean curvature compact Cauchy surfaces. Introduction.Let (M, g) be a CMC cosmological space-time, i.e. a space-time with a compact constant mean curvature Cauchy surface (Σ, g, K). The main focus will be on the vacuum case in 3 + 1 dimensions although we will occasionally consider generalizations to non-negative energy conditions and higher dimensions.A fundamental issue in general relativity is to understand the global structure of (M, g), and in particular the evolution of the geometry of the CMC foliation Σ τ generated by the CMC slice Σ. Singularities of (M, g) will generally form in finite proper time, both to the future and to the past of Σ. Roughly, these may correspond either to big bang or big crunch singularities of the space-time as a whole, or to localized gravitational collapse within only parts of the space-time. The understanding of the mechanism and structure of such singularity formation is of course a central issue in general relativity.Here we concentrate instead on the simpler situation where there is no singularity formation (in finite proper time), say to the future of Σ. Thus, assume (M, g) is geodesically complete (time-like and null) to the future of Σ. The basic issue then is to understand the asymptotic or long-time future behavior of the geometry of the CMC slices Σ τ and of the full space-time (M, g).Similar issues arise, and have been more fully investigated, in connection with globally hyperbolic, geodesically complete space-times with an asymptotically flat Cauchy surface, (purely radiative space-times). Thus, following Penrose, starting from an asymptotically flat initial data surface, one would like to understand the asymptotic structure of the resulting maximal globally hyperbolic space-time in terms of a conformal compactification leading to the structures of Scri; I, I + and I 0 . A great deal of work has been done and is ongoing in this direction, cf. [15], [21], [24] and references therein.The issues we consider then are cosmological analogues of this question. In principle, this should be a simpler situation to analyse, since there is no spatial infinity; compact slices are easier to deal with than non-compact slices.Vince Moncrief, together with Arthur Fischer, has begun a program to understand this issue, cf.[16]-[20] and further references therein. Independently, the author has also initiated such a program, cf. [1]. Both programs have a number of features in common and agree in certain special cases. In the end, they should also lead to the same overall description of the asymptotic behavior at future infinity. However, both the techniques and the point of view of these two approaches are Partially supported by NSF Grant DMS 0072591.

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Group coancestry-controlled selection in a Pinus sylvestris L. breeding program

Cited by 5 publications

References 20 publications

Gain and diversity in advanced generation coastal Douglas-fir selections for seed production populations

Gain and diversity in advanced generation coastal Douglas-fir selections for seed production populations

Improving initial trials in tree breeding using kinship and breeding values estimated in the wild: the case of Prosopis alba in Argentina

Asymptotic behaviour of future-complete cosmological spacetimes

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