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The maintenance of genetic diversity across seed orchard generations is an important management objective. Here, we used Pinus tabuliformis Carrière as a model to explore the extent of genetic diversity across the species’ breeding activities through their corresponding seed orchard generations. We utilized a large number of simple sequence repeat (SSR) markers selected from P. tabuliformis transcriptomic data, and then assessed the effect of marker number on genetic diversity and genetic relationships of individuals across orchard generations. In total, we designed 125 SSR markers, of which 39 were polymorphic and used in the present study. The genetic diversity and genetic distance parameters tended to increase with an increase in loci number and a stable trend was reached at 24 SSRs. The selected optimal 24 SSR markers were further used to assess the genetic diversity across seed orchard generations, and a decreasing trend was detected with the advancement of orchard’s generations. Genetic distance analysis indicated that individuals in the 2nd generation orchard were more closely related compared with those of the 1st generation and the 1.5 generation. This study provided valuable information on the effect of selection and breeding on genetic diversity and highlighted its role for effective seed orchard management.

Prior to Ginkgo leaf harvest, we implemented four exogenous applications of salicylic acid (SA: 50, 80, and 100 mg·L−1) or methyl jasmonate (MJ: 20, 40, and 80 mg·L−1) as leaf spray to investigate their effect on flavonoids content and related enzyme activity. Compared with the control, a significant increase of 12% and 26% in flavonoid content was observed 7 days after the first application of 100 mg·L−1 SA and 20 mg·L−1 MJ, respectively; both were determined to be the best treatments. Operationally, administering either elicitor (SA or MJ) 1 week prior to leaf harvest is deemed to be the most practical and economic option. Additionally, enzymes activity involved in flavonoid metabolism (phenylalanine ammonia-lyase, cinnamate 4-hydroxylase, and 4-coumarate:coenzyme A ligase) and antioxidants (peroxidase, superoxide dismutase, and catalase) significantly increased in most SA and MJ treatments. The results strongly support Ginkgo leaf response to SA- or MJ-induced stress through increased nonenzymatic antioxidant compounds (flavonoids) and activity of antioxidant enzymes.

Pollination dynamics was studied in a first-generation Platycladus orientalis (L.) Franco seed orchard with pedigree reconstruction using eight nuclear and four chloroplast SSRs. The pedigree reconstruction assigned 371 of 448 studied seeds to one of the orchard’s 192 candidate male parents and showed a high level of outcrossing and pollen contamination in the orchard’s seed crop. While the orchard’s seed population showed greater allelic richness compared with the parental population, a few alleles present in the parental population were missing in the seed crop. Additionally, we detected no significant correlation between male reproductive energy (pollen yield) and male reproductive success; however, uneven parental contribution was also observed. Pollen management practices were recommended to ensure the maintenance of genetic diversity in the seed crops and increase in genetic gain.

To understand the contemporary and anticipated future (future 30–50 years) distribution of Chinese wild yellowhorn (Xanthoceras sorbifolium Bunge) and to improve the species’ in situ conservation strategy within the network of China’s National Nature Reserves (NNR), we used BiodiversityR to predict the species’ distribution utilizing the “always-suitable” map concept. We then delineated the always-suitable distributions with the existing NNRs to identify potential conservation areas using an approach that concurrently considered spatial distribution, gap analysis, the role of climate change, and economic analyses. Seven bioclimatic variable predictors and 12 environmental niche modelling submodels successfully contributed to the final model assembly (AUC = 0.916, κ = 0.398). The species range delineation indicated that 71 of the 427 NNRs were included in the always-suitable area, accounting for 26 007 km2 (1.58%) of the species total distribution. This mapping endeavour highlighted the negative impact of climate change with a projected 15%–20% habitat decline and expected species’ distribution centers shifting from the country’s northwest to the southeast. Our results predict the continuous deterioration of X. sorbifolium because of its existing utilization as an oil source and its increased bioenergy potential. The adoption of a flexible management strategy embracing acceptable trade-offs between conservation and utilization within China’s NNRs could effectively alleviate the expected species decline.

This paper considered whether it was possible to activate nonavailable phosphorus (P) with tree root organs in lateritic soils. We investigated the cell wall content and P-solubilizing activity of xylem and phloem from six different sizes of roots from 10, 22, and 34 year old plantations of the Chinese fir Cunninghamia lanceolata (Lamb.) Hook. We found that, on average, cell wall content accounted for 81.07% of the root biomass (dry mass), and the mean solubilization of aluminum-bound phosphate by cell wall preparations was 1.89 g·kg−1. Tissue type (i.e., phloem or xylem) had a significant effect on cell wall content, with more cell wall material in the xylem, whereas P-solubilizing activity was greater in the phloem. In addition, the cell wall content of xylem increased with increasing root diameter, but P-solubilizing activity did not. A significant difference was also observed among the P-solubilizing activity of the three age classes, with lower P-solubilizing activity in the roots of 10 year old trees than in those of 22 and 34 year old trees. Since the establishment of Chinese fir plantations is increasing in southern China, where lateritic soils are widely distributed, the findings of the present study undoubtedly provide pertinent information for improving the utilization of nonavailable P by the cell walls of tree roots.

The genetic gain and gene diversity of seed crops from a 1.5-generation clonal seed orchard of Pinus koraiensis Siebold & Zucc. were estimated under consideration of parental genetic values and fecundity variation. Fecundity variation among clones was estimated for 5 consecutive years (2010–2014) as the sibling coefficient, which was drawn from clonal contribution to the total production of seed conelet. To monitor gene diversity, status number was estimated by the integration of fecundity variation and group coancestry. Group coancestry was calculated as the average of genetic relatedness (coancestry) among orchard clones. The averages of conelet production were high in 2010 and 2011, moderate in 2013 and 2014, and poor in 2012 with a grand mean of 13.7. Correlation analysis showed that good conelet producers consistently gave good production. Cumulative distribution of clonal conelet production was presented as a function of the total conelet yield, and this distribution indicated deviation from the expected clonal equal production. Group coancesrtry was 0.0096, indicating minimal loss of gene diversity. Status number and genetic gain were higher in good than in poor conelet production years, highlighting the importance of fecundity variation in determining the genetic gain and gene diversity of seed orchard crops.

Estimating seed orchards’ maternal and paternal gametic contributions is of importance in assessing the genetic quality of seed crops. The advantage of full over partial pedigree reconstruction in investigating the mating dynamics in a lodgepole pine (Pinus contorta Dougl. ex. Loud. ssp. latifolia Engelm.) seed orchard population (N = 74) was demonstrated using nuclear and chloroplast microsatellite markers. We analyzed offspring of equivalent sample sizes representing full (bulk seed with unknown maternal and paternal parentage (n = 635)) and partial (11 maternal family arrays (n = 619)) pedigree reconstruction methods. Small differences in selfing rate, gene flow, and male reproductive success were observed between the two methods; however, the full pedigree reconstruction enabled simultaneous estimation of female-related fertility parameters (female reproductive success and effective number of maternal parents) that partial pedigree reconstruction could not provide. The use of bulk random sample of seed from orchards’ crops is recommended when male and female fertility parameters, as well as selfing and contamination rates, are needed for seed orchards’ seed crops genetic rating.

Seed orchards’ parental reproductive success is often assessed through surveys of seed- and pollen-cone production (reproductive investment). Although the reliability of this approach has been questioned, its speed and ease made it the method of choice for providing approximate estimates for the genetic quality and quantity of seed orchard crops. In this study, reproductive investment data from various female and male phenotypic assessment methods from three seed orchards (lodgepole pine ( Pinus contorta Dougl. ex. Loud. var. latifolia Engelm.), Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco), and western larch ( Larix occidentalis Nutt.)) were compared with reproductive success estimates based on DNA fingerprinting and parentage analyses. The use of reproductive investment as a proxy to reproductive success on estimating seed crop’s volume genetic worth and diversity (measured by effective number of parents) was evaluated. Regression analyses indicated that the phenotypic assessment methods reflect the true parental reproductive success and that estimates of seed- and pollen-cone volume production appear to be the most appropriate indicators of female and male reproductive success, respectively. Although the best combination of female–male survey methods produced inflated effective number of parents estimates, the genetic worth estimates were similar to those based on DNA, highlighting their robustness to fertility variation assessment.

Adelgids (Hemiptera: Adelgidae) gall vegetative and reproductive shoots of interior spruce (Picea spp.), causing growth impairment, seed loss, and aesthetic decline. We tested the theory that susceptibility to galling is under genetic control in spruce. We assessed natural galling incidence in a spruce progeny test located in southern British Columbia. The experiment was composed of a replicated 13-parent incomplete, partial diallel with 42 full-sib families. Moderate evidence of genetic control of susceptibility–resistance was observed with individual narrow-sense heritability of 0.17. We observed considerable genetic variation among parents for resistance to gall formation as shown by high heritability (0.87) of family means. Breeding values for parental susceptibility to adelgid attack ranged between 0.25 and 0.76, indicating that selection for reduced susceptibility would be successful. The benefits of screening for resistance to adelgid attack are discussed in relation to adelgid pest management, insect’s life-cycle, and tree health.

A breeding program where clones or clone mixtures are deployed through somatic embryogenesis of superior genotypes produced from elite-parent crosses was evaluated by simulation. A recurrent-selection scheme for general combining ability was considered with a breeding population size of 100 individuals. The population was assortatively pair-crossed with offspring cloned in a progeny test to facilitate forward selection of the next generation. Apart from crosses for the population advancement, "elite" crosses were made among 10 top-ranking individuals in each generation. These crosses differed in their propensity to produce somatic embryos (defined as induction success rate); the impact of this variable propensity on genetic response for two traits in selected 10-clone deployment mixtures was evaluated. The two traits considered in this study can be regarded as "productivity" and "quality". The results revealed that variation in success of clonal propagation does not necessarily lead to a reduction in potential genetic gains from selected clonal mixtures. This can be explained by the relatively small variation that exists among elite crosses, as opposed to large within-family variation. This large within-family variation provides ample potential for selecting superior offspring genotypes, even though they may have not originated from crosses among the very best of the elite parents. This conclusion holds for a range of heritability, correlations between traits, and their relative economic importance.

Clonal replicates of Chamaecyparis nootkatensis (D. Don) Spach rooted cuttings (ramets) originating from pruned donor hedges (ortets) were grown for 3 years in a completely randomized common garden in southwestern British Columbia. Ramets were cut when ortets were 3, 7, 11, and 15 years old; selected ramets were also serially propagated for one, two, or three cycles, 4 years apart. Serial propagation and physiological and chronological aging effects of ortets on ramets were evaluated for photosynthetic and gas exchange parameters, rooting, height, biomass, and cold hardiness. Genotypic variation typically exceeded treatment differences. Excepting several genotypes, serial propagation had no significant effect on aging for pruned plants. Some genotypes had crooked or plagiotropic growth. These differences strengthened with ortet age, but serial propagation effects varied with genotype. Rooting success was similar across treatments. Detrimental effects of ortet aging were detected only at age 15. Clonal rooting differences were obscured by age 7; 15-year-old material had the lowest rooting success and smallest individuals. Serially propagated ramets from 15-year-old ortets had smaller shoots. No consistent trends were caused by age or serial propagation for other traits. Serial propagation can successfully mass produce tested elite yellow-cedar planting stock up to age 15.

Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) zygotic seedlings and seedlings produced through somatic embryogenesis were grown in a field test on southern Vancouver Island, British Columbia. The two stock types were compared in a number of adaptive attributes evaluated during two growing seasons (1999 and 2000). The attributes were related to gas exchange, water relations, phenology, and fall frost hardiness. In both years, somatic and zygotic seedlings had similar rates of net photosynthesis in optimum and reduced light conditions, similar mesophyll conductance, and dark respiration rates. Small differences (P [Formula: see text] 0.05) were found for water relation attributes measured on irrigated plants: intrinsic water use efficiency (WUEi), transpiration (E), stomatal conductance (gwv) and midday xylem water potential (Ψ). Somatic seedlings had marginally higher E and gwv and lower Ψ in 2000 and lower WUEi in 1999 and 2000. Zygotic seedlings had higher WUEi because of their lower gwv while maintaining the same rates of net photosynthesis as somatic seedlings. There were no differences between somatic and zygotic seedlings in frost hardiness throughout the fall. Zygotic and somatic seedlings had similar timing of spring bud break pointing to a comparable level of spring frost hardiness in both stock types. Findings from this study indicate that somatic and zygotic seedlings had a similar pattern of physiological performance throughout 2 years of assessment.

A common garden study investigated growth, morphology, and cold hardiness of yellow-cedar (Chamaecyparis nootkatensis (D. Don) Spach) seedlings originating from seed that had matured at an accelerated rate. This early maturing seed, produced at a low-elevation southern Vancouver Island seed orchard, was known to have similar germinability and seedling morphology as high-elevation normally maturing seeds. Population differences in 3-year-old seedlings were evident only in shoot harvest index (ratio of stem/shoot dry weight). The amount of stem elongation that occurred prior to the formation of secondary foliage (juvenile height) and harvest index were weakly correlated with source elevation at which maternal parents were developed. Traits that exhibited no discernable differences between progeny from early maturing seed and the control normally maturing seed included midwinter cold hardiness testing and selected measures of shoot morphology and growth. The control seedlings had significantly less height growth prior to the transition of primary foliage to secondary foliage formation than did the seedlings originating from early maturing seed.

Variation at 41 putative genetic loci, uncovered by 29 single or low-copy nuclear probes of restriction frag - ment length polymorphism, was examined in western redcedar (Thuja plicata Donn. ex D. Don). Only 8 of the 29 probes produced polymorphisms when HindIII-digested DNA samples from 18 trees from each of five geographic re- gions (90 trees in total) covering the entire geographic range of the species were analysed. The eight polymorphic probes were used against an additional sample of 160 trees (for a total of 250 trees or 50 per region) to permit higher resolving power of differentiation between the regions. Species-level expected heterozygosity (or total gene diversity, HT) was estimated at 0.070, a low value that is quite similar to that at isozyme loci. Nei's genetic distances between the regions were quite small and DST, the average gene diversity between populations, was only 0.0042, indicating a low degree of differentiation among geographic regions. No private alleles were found, and low-frequency alleles were widespread across the species range. These results suggest that the present range of western redcedar is occupied by descendants of a small number of lineages from a single refugial population that survived the drastic changes in clima - tic conditions associated with the last ice age. Resume : Les auteurs ont etudie la variabilite genetique chez le cedre de l'Ouest ( Thuja plicata Donn ex. D. Don) au niveau de 41 loci genetiques presumes reveles par 29 sondes nucleaires, a copie unique ou a faible nombre de copies, du polymorphisme de la longueur du fragment de restriction. Seulement 8 des 29 sondes ont revele des polymorphis- mes lorsque les echantillons d'ADN etaient digeres par HindIII. Ces echantillons etaient representatifs de 18 arbres pour chacune de cinq regions geographiques (90 arbres au total) couvrant l'ensemble de l'aire de repartition naturelle de l'espece. Les huit sondes revelant du polymorphisme ont ete confrontees a un echantillon additionnel de 160 arbres (pour un total de 250 arbres ou 50 par region) afin de mieux quantifier le degre de differenciation entre les regions. L'heterozygotie esperee au niveau de l'espece (ou diversite genetique totale, HT) a ete estimee a 0,070, ce qui repre- sente une valeur faible mais similaire a celle decoulant de loci d'isoenzymes. Les distances genetiques de Nei estimees entre les regions etaient assez faibles et DST, la diversite genetique moyenne entre les populations, affichait une valeur aussi basse que 0,0042, indiquant un faible degre de differenciation entre les regions geographiques. Aucun allele unique a une seule population n'a ete observe et les alleles de faible frequence etaient bien repartis dans toute l'aire de repartition naturelle. Ces resultats suggerent que l'aire actuelle de repartition du cedre de l'Ouest est occupee par des descendants representatifs d'un petit nombre de lignees originant d'une population refuge unique ayant survecu aux changements drastiques dans les conditions climatiques survenus au cours de la derniere periode glaciere.

Frequency data from six polymorphic allozyme loci and measurements of six quantitative traits were used to examine geographic differentiation among 65 British Columbia provenances of red alder (Alnus rubra Bong.). Principal components analysis showed that variation in quantitative traits can be reduced to two underlying dimensions, one representing general vigor including the termination of the growing period and the other being the start of the growing period. Canonical correlation analysis among quantitative traits, allozyme frequencies, and geographic variables revealed complex associations of quantitative traits with the latitude, distance to the coast, and elevation of the seed source. There were no significant correlations among allozyme frequencies and quantitative traits, but the frequency of the most common allele at most loci decreased with latitude. Further, cluster analysis based on Nei's genetic distance revealed a strong differentiation among island and mainland provenances at one allozyme locus. This differentiation can be interpreted as a result of migration from two different refugia since the last glaciation. The island populations presumably originate solely from isolated coastal refugia west of the Cordilleran ice sheet, while mainland populations were also recruited from areas south of the ice. Resume : Les auteurs ont etudie la differenciation geographique parmi 65 provenances d'aulne rouge (Alnus rubra Bong.) de Colombie-Britannique a partir de donnees de frequences alleliques pour six loci polymorphes d'alloenzymes et des mesures pour six caracteres quantitatifs. Les resultats de l'analyse en composantes principales ont demontre que la variabilite des caracteres quantitatifs pouvait se resumer en deux dimensions sous-jacentes, l'une representant la vigueur generale et incluant la fin de la periode de croissance et la seconde, definie par le debut de la periode de croissance. L'analyse de correlations canoniques realisee entre les caracteres quantitatifs, les frequences d'alloenzymes et les variables geographiques a fait ressortir l'existence de relations complexes entre les caracteres quantitatifs et la latitude, la distance de la cote et l'altitude des sources de semences. Il n'y avait pas de correlations significatives entre les frequences d'alloenzymes et les caracteres quantitatifs, mais la frequence de l'allele le plus commun diminuait avec la latitude pour la plupart des loci. De plus, l'analyse de regroupement a partir des distances genetiques de Nei a revele une differenciation marquee entre les provenances insulaires et celles du continent pour un locus d'alloenzymes. Cette differenciation pourrait s'expliquer par le resultat d'une migration a partir de deux refuges distincts depuis la derniere periode glaciaire. Les populations insulaires auraient comme seule origine presumee des refuges isoles sur la cote a l'ouest du glacier de la Cordillere, alors que les populations continentales decouleraient de refuges situes au sud du front glaciaire.

Supplemental mass pollination (SMP) success rate in a mature Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seed orchard was studied with the aid of a unique electrophoretically detectable allozyme marker. Operational applications, and branch applications that were carried out one, two, or three times, were conducted during the orchard's maximal pollen release (i.e., the height of pollination). No significant increase in seed-yield traits (total number of seeds per cone, number of filled seeds per cone, and seed efficiency) was observed between wind-pollinated and SMP-treated (operational and one and multiple branch visits) cones. However, multiple branch visits (18%) showed significant increase in SMP success rate when compared with the operational visit (8%) or the one branch visit (9%) results. No significant increase in SMP success rate was obtained when the number of branch visits was increased from two (17.8%) to three (17.9%). It was concluded that operational SMP had the potential to improve the genetic value of the treated Douglas-fir crops even under high pollen load. The degree of improvement is dependent directly on SMP fertilization success and indirectly on the genetic value differential between the supplemented and the orchard's ambient pollen, the frequency of application, and the quality of the pollen applied (i.e., viability).

In 1987, a study was initiated to determine the properties of seed from apparently premature cones of yellow-cedar (Chamaecyparisnootkatensis (D. Don) Spach) on southwestern Vancouver Island. After pollination with fresh pollen in February, all cones showed signs of maturation (i.e., drying and shedding) by December. Samples of these 1-year-old cones were collected for seed extraction and germination tests. Germination ranged between 10 and 42% for isolated cones (i.e., bagged) and between 0 and 25% for unisolated cones. Similar germination results were obtained for the 1988 and 1989 cone crops. Anatomical observations revealed that the 10-month-old embryos were similar in both size and shape to embryos from 2-year-old seeds. It was concluded that transplanting yellow-cedar trees to warmer, low-elevation sites enabled seed cones to continue development without significant delay caused by dormancy induced by cold temperatures at higher elevations. This alteration of normal phenology reflects the impact of environmental contingencies on development.

Trace-element profiles for seeds collected from 10 International Union of Forest Research Organization provenances of Sitka spruce (Piceasitchensis [Bong.] Carr.) from the Pacific Northwest were determined by X-ray energy-dispersive spectrometry. Stepwise discriminant analyses were used to examine potential significant differences among groups and separate samples were used as unknowns to test each discriminant function. Three analyses were made, the first to discriminate among the 10 provenances, the second to discriminate among the five Canadian provenances only, and the third to discriminate the Canadian provenances grouped by soil types at provenance origin. Significant differences (P

Spatial variability in heights of 8-year-old Douglas-fir in a IUFRO provenance–progeny transfer test was analyzed using trend surface analysis to differentiate genetic and environmental effects on tree height. The test installation was located in the University of British Columbia Research Forest, and was a randomized incomplete block design with three replications. Only the 25 provenances that were replicated in each block and had a balanced data set (eight families, five trees per family) were used. Trends were fitted to the average height of each replicate of each provenance, and also to the average size of the largest and smallest families per replicate. Interpretation was based on the assumption that the effects of microsite (mainly grass invasion of one block) were defined by the trend surface, while genetic effects were represented by the residuals from the trend. The data had previously been analyzed by ANOVA methods and these results were contrasted with the results using trend surface analysis. Trend surface analysis generally gave results similar to ANOVA, but in some cases resulted in different conclusions. Additional insights into the interaction of genotype and environment were obtained. Trend surface analysis is proposed as a useful supplement to analysis of variance in provenance transfer studies. Potential problems in using the method are discussed.

Genetic variation at 24 enzyme loci was studied for 10 IUFRO populations of Sitka spruce (Piceasitchensis (Bong.) Carr.). The average proportion of polymorphic loci per population was 0.51 ± 0.02 and the average proportion of heterozygous loci per individual was 0.15 ± 0.03. The following generalizations were advanced: (1) the amount of genetic polymorphism varied considerably from locus to locus; (2) many populations were similar in the amount and pattern of genetic variation for most loci; (3) but some loci had large differences among populations.Eight percent of the gene diversity was attributed to interpopulation differentiation; 92% of the total gene diversity resided within populations. Pairwise comparisons of genetic distances averaged 0.014, a value which reflected very little differentiation between geographic sources.

Seeds from four ramets in each of six clones of 17-year-old Douglas-fir, Pseudotsugamenziesii (Mirb.) Franco, grown in a Saanichton, B.C., seed orchard on common rootstock were examined by X-ray energy-dispersive spectrometry to determine variations in trace element profiles. These profiles were analysed by discriminant function analysis and shown to be specific for each clone with 80.4% of seeds being correctly classified to original clone. Since the ramets were all grown in a similar orchard environment, these results support the hypothesis that elemental uptake by seeds of Douglas-fir is under genetic control.

Seeds from 21 populations of Piceamariana (Mill.) B.S.P. from five forest sections of the boreal forest regions in Newfoundland were analyzed for electrophoretically detectable variation in 15 proteins coded by 23 genetic loci. On the average, 38% of the loci per population were polymorphic, the number of alleles per locus was 1.44, and the expected and observed heterozygosities were 0.107 and 0.120, respectively. Contingency χ2 analysis for homogeneity of allele frequencies indicated differentiation (P