Protocols for Rating Seed Orchard Seedlots In British Columbia

2015

Forest policy in Flanders (Belgium) strongly promotes the use of indigenous hardwoods, among which wild cherry (Prunus avium L.), for re- and afforestation and for stand conversion,. This line of policy generates a strong demand for high quality forest reproductive material, which cannot be met by the currently available basic material. The selection and breeding programme attempts to remedy the discrepancy between supply and demand by creation of a new generation of clonal seed orchards characterised by (i) a high yield and (ii) a high genetic quality and diversity of the offspring. This goal was achieved by selection of 52 genotypes based on half-sib progeny trials. Yield and genetic quality of the offspring was enhanced to a further extend by adjusting the spatial design of the seed orchard to the phenologically and gametophyticaly cross-compatibility of the selected genotypes. Background pollination is reduced to a minimum by establishment of the seed orchard at a minimum distan...

TAG Theoretical and Applied Genetics, 2001

Genetic gain and the gene diversity of seed crops from clonal seed orchards were formulated considering genetic selection, fertility variation and pollen contamination, and compared for five different management strategies. Genetic response was studied as a function of orchard management tactics. Management variables included the proportion of clones left after genetic thinning and/or selective seed harvesting. Formulae were derived to calculate gene diversity (expressed as group coancestry or status number) based on the sex ratio in an orchard population. The influence of having different sets of clones serving as seed parents, or pollen parents, or as both, was analysed. In addition, the impact on genetic gain and the gene diversity of seed crops was studied quantitatively as a function of the quantity and quality of gene flow from outside the orchard. The negative impact of fertility variation among orchard genotypes on the gene diversity of the seed crop was quantified. Numerical examples were given to illustrate the impact of orchard management alternatives on genetic gain and gene diversity. The formulae and results of this study can be used for identifying favourable alternatives for the management of seed orchards.

2009

The objective of seed orchard management is to maximize the genetic gain while maintaining sufficient level of genetic diversity in the orchard’s crops; however, balancing these two parameters is a challenging task. Eight polymorphic nuclear microsatellite DNA markers were used to construct the full pedigree of 801 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) bulk seeds from 49 orchard parents and 4 external supplemental mass pollination (SMP) donors. Parental balance curves indicated that 80% of the gametes were produced by 23, 45 and 37% of females, males and clones, respectively. Contamination was found to be 10.36% with overhead cooling applied. Selfing rate was found as 15.23% due to the over representation of few orchard clones. The aggregate SMP (internal & external) success rate was estimated to be 15.02%. The female, male and clonal effective population size (Ne) was estimated to be 6.49, 26.00 and 13.70, respectively. The reduction of Ne is mainly the result of unequ...

Scandinavian Journal of Forest Research

New Forests, 2012

To test how efficiently plantations and seed orchards captured genetic diversity from natural Anatolian black pine (Pinus nigra Arnold subspecies pallasiana Holmboe) seed stands, seed sources were chosen from 3 different categories (seed stands (SS), seed orchards (SO) and plantations (P)) comprising 4 different breeding zones of the species in Turkey. Twenty-five trees (mother trees) were selected from each SS, SO and P seed sources and were screened with 11 Random Amplified Polymorphic DNA (RAPD) markers. Estimated genetic diversity parameters were found to be generally high in all Anatolian black pine seed sources and the majority of genetic diversity is contained within seed sources (94%). No significant difference in genetic diversity parameters (numbers of effective alleles, % of polymorphic loci and heterozygosity) among seed source categories was found, except for a slight increase in observed heterozygosities in seed orchards. For all seed source categories, observed heterozygosity values were higher (H o = 0.49 for SS, 0.55 for SO and 0.49 for P) than expected ones (H e = 0.40 for SS, 0.39 for SO and 0.38 for P) indicating the excess of heterozygotes. In general, genetic diversity in seed stands has been transferred successfully into seed orchards and plantations. However, the use of seeds from seed orchards can increase the amount of genetic diversity in plantations further. The study also demonstrated that number of plus-tree clones (25-38) used in the establishment of seed orchards was adequate to capture the high level of diversity from natural stands.

New Forests, 2019

Genetic variation in reproductive phenology among clones in a seed orchard affects the genetic efficiency of the orchard. Our objective was to evaluate genetic variation in reproductive phenology of Pinus patula clones in a seed orchard and the amount of overlap with pollen dispersal in natural stands. In 2014 and 2015, phenology of female and male strobili was recorded on 31 clones in the orchard, and phenology of male strobili was measured on 10 trees in each of four nearby natural stands along an elevational transect. Onset and end dates, and length of female receptivity (F_onset, F_end and F_length) and pollen dispersal (M_onset, M_end and M_length) were calculated, and genetic parameters were estimated. Differences between years in M_onset were larger in the natural stands than in the orchard, but there was a large overlap between the orchard and natural stands. A negative linear relationship with elevation was found for M_end and M_length in natural stands along the elevation transect. Genetic variation was detected for most reproductive phenology traits in the orchard. Genetic control was stronger for M_onset and M_length (H 2 c ≥ 0.54) than for female receptivity traits (H 2 c ≤ 0.38). Most phenological traits showed high genetic stability in both years (r B ≥ 0.76). We found a positive genetic correlation (r = 0.67) between F_onset and M_onset, suggesting there is a risk of selfing among clonal ramets. Moreover, the overlap between female receptivity in the orchard and pollen dispersal in neighboring natural stands indicates a risk of genetic contamination in the orchard, particularly for latephenology clones.

Annals of Forest Science, 2010

Pollination dynamics was studied in a Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seed orchard using 8 nuclear microsatellite markers and pedigree reconstruction.

2008

Effective population size as a parameter closely correlating with the genetic and genotypic diversity of the seed orchard output is an important indicator of seed orchard functioning. It is determined by the variation of male and female gametic contributions of parental genotypes (including those outside the seed orchard), influenced by the variation in male and female gamete production, reproductive phenology, pollen dispersal within seed orchard and other factors. The assessment of fertility and phenological variation requires labor and finances. We tested empirically what is the relative importance of these factors for effective population size (status number) estimation by gradual adding one-by-one in the order of labor requirements (female contribution, male contribution, reproductive phenology, pollen dispersal) in three Scots pine (Pinus sylvestris L.) seed orchards in central Slovakia. The study has shown that in old, fully fructificating seed orchards, effective number of c...

New Forests, 2008

This study investigates the rates of grafting and planting errors that occur in seed orchards, and evaluates their effects on the genetic diversity and relatedness of genotypes. The study used three clonal Scots pine seed orchards of differing ages and clonal composition located in the forest districts of Susz, Pniewy and Zdrojowa Góra, Poland. Maximum breeding ability within a seed orchard requires isolated from external sources of pollen, and have no alien genotypes inside the orchard. We used 13 isoenzyme markers to determine the genotypic identity of ramets and compared the number of genotypes of the actual current ramet population (W1) with genotypes comprising the originally intended plus trees (designated as W0) to estimate the genotypic assignment error rate per orchard. For both W0 and W1, we calculated the effective number of clones and the relative effective number of clones. Ramet assignment errors were detected in all three seed orchards. Gnotypic errors ranged from 5.8% to 37.7% across orchards. A total of 46 alleles were found, with the mean number of alleles per locus ranging from 2.77 to 3.23. At individual loci, the level of observed heterozygosity was variable. Alien genotypes had negligible effects on seed orchard heterozygosity. The Fst values between seed orchards amounted to 0.6% between Susz and Pniewy and 1.1% between Susz and Zdrojowa Góra. The effect on genetic variation of ramet assignment errors was small and influenced genetic diversity only in the case of the Susz seed orchard. However, our results suggest that negative effects of alien genotypes can occur on breeding value of seeds from analysed seeds orchards.

Genetika, 2013

Effective population size as a parameter closely correlating with the genetic and genotypic diversity of the seed orchard output is an important indicator of seed orchard functioning. It is determined by the variation of male and female gametic contributions of parental genotypes (including those outside the seed orchard), influenced by the variation in male and female gamete production, reproductive phenology, pollen dispersal within seed orchard and other factors. We assessed male and female fecundity, as well as temporal course of male and female flowering in two seed orchards of Pinus nigra ARNOLD and Fraxinus excelsior L./F. angustifolia VAHL. in Slovakia. In both cases, male and female gametic contributions of plus-tree clones were modeled on the basis of fecundity and flowering phenology, and were used to calculate status number as an estimator of effective population size. In the seed orchard of Pinus nigra, marker-aided verification of clonal fidelity revealed unexpectedly ...