Establishment Of Seed Orchards Research Articles

Ex situ' management including seed orchard establishment for Native Guava ('Rhodomyrtus psidioides') affected by Myrtle Rust

Ex situ' management including seed orchard establishment for Native Guava ('Rhodomyrtus psidioides') affected by Myrtle Rust

Near infrared spectroscopy as a tool for predicting growth habit and gender of Araucaria angustifolia

ABSTRACTAraucaria angustifolia is the only native conifer of economic importance in Brazil for wood and nut production. There are several constraints to the genetic improvement of the species. Vegetative ramets display strong and lasting plagiotropism, which is difficult to pre-select for, and it is a dioecious species. Trees reach reproductive maturity at 12–15 years old and there is currently no method to distinguish the sex of the plant before this time. Early detection of plagiotropism or early identification of plant sex would improve efficiencies in breeding programs and seed orchard establishment. Therefore, we investigate the potential of near infrared (NIR) spectroscopy analysis as a tool for predicting growth habit and gender of A. angustifolia. Spectra from needles at the stem apex were taken from 12-month-old plants for growth habit calibration using the presence or absence of a lateral shoot to distinguish between future growth habits. Model validation was done on needles from the apical shoots of orthotropic trunks and from clones displaying plagiotropic growing habit. For plant sex, spectra were collected on wood from bark windows and from multiple needles located midway up the main stem. Needle spectra from individual plants were averaged to produce a single spectrum per plant. Multivariate analysis was performed on spectra and associated reference data. Results indicate that NIR has the potential to predict sex and growth habit and may be a useful screening tool in improvement of Araucaria.

Forward selection in a maritime pine polycross progeny trial using pedigree reconstruction

Molecular markers were used for paternity recovery in a maritime pine ( Pinus pinaster Ait.) polycross trial, facilitating forward selection. Different breeding strategies for seed orchard establishment were evaluated by comparing genetic gains and diversity. This work opens up new perspectives in maritime pine breeding. Polycross mating designs are widely used in forest tree breeding to evaluate parental breeding values for backward selection. Alternatively, polycross progeny trials may be used to select the best trees on the basis of individual breeding values and molecular pedigree analysis. This study aimed to test such a forward selection strategy for the maritime pine breeding program. In a maritime pine polycross trial, progeny with higher breeding values for growth and stem straightness was first preselected with or without relatedness constraints. After paternity recovery, the preselected trees were ranked on the basis of their breeding values, estimated from the recovered full pedigree. Finally, the best candidates were selected with three different strategies (forward, backward, mixed) and three levels of coancestry constraints to establish a virtual clonal seed orchard. Complete pedigrees were successfully recovered for most of the preselected trees. There was no major difference in expected genetic gains between the two preselection strategies which differed for relatedness constraints. Genetic gains were slightly higher for forward selection than for classical backward selection. This seminal study opens up new perspectives for using forward selection within the French maritime pine breeding program.

Growth Performance and Heritability Estimation of Acacia crassicarpa in a Progeny Trial in eastern Thailand

Abstract Growth performance and heritability were studied in a progeny trial of Acacia crassicarpa in Chacheongsao province, eastern Thailand in order to provide information on suitable families for seed improvement and production. A randomized complete block design (originally 8 blocks, 80 family plots/block, 4 trees/plot) of the best 80 half-sib families selected from 7 provenances was thinned at ages 2.5, 4 and 5 years based on growth and tree form and so that there was one tree/plot remained at the stage of present study. All remaining trees were measured for diameter at breast height (DBH), tree height (H), individual volume (VOL) and stem form (straightness and forked height) at ages 12, 12.5, 13 and 13.5 years, respectively. Narrow sense heritability (h 2) based on family was estimated for each characteristic. Analysis of variance showed that there were highly significant differences among families at the four ages for DBH, H and VOL. Stem straightness and forked height were not significantly different among families. The heritability of DBH was increased as trees were mature (h 2 = 0.236, 0.285, 0.288, and 0.291) but those of H and VOL were a little decreased. The heritability of stem straightness was very low (0.013) and that of forked height was also low (0.138). The results implied that the tree breeding of A. crassicarpa could improve DBH, H and VOL considerably. Further selection testing is required to increase the heritability of stem form. The measured data would be useful for tree improvement and seed orchard establishment of Acacia crassicarpa.

Genetic and variation analyses of growth traits of half-sib Larix olgensis families in northeastern China

To gain a better understanding of genetic variation of growth traits in Larix olgensis, we investigated the progeny of 60 half-sib families of L. olgensis grown in a seed orchard in northeastern China. Tree height (H), basal diameter, and diameter at breast height (DBH) were measured at four different ages (i.e., at 4, 6, 8 and 10 years of growth). Significant differences among all the variation sources were observed during the different growth years. During the four measured years, phenotypic coefficients of variation (PCVs) of all traits ranged from 17.83 to 33.01 %, with heritabilities varying from 0.531 to 0.798. A correlation analysis uncovered extremely significant positive correlations among all traits within or among years. These high heritabilities and large PCVs were beneficial for the early selection of superior families. Using a comprehensive evaluation method, different families were selected as superior on the basis of different selection rates during each measured year, with families L78, L64, L63, L48, L13 and L14 selected across all measured years. At the 10th growth year, the optimal time to identify superior L. olgensis families, the selected families (L78, L64, L63, L48, L13 and L14) displayed higher H and DBH values, which corresponded to genetic gains of 8.31 and 16.82 %, respectively. In addition to the identification of superior female parents for improved seed orchard establishment, the findings generated by our study can serve as a theoretical foundation for early selection of L. olgensis families.

Variation and Stability in Female Strobili Production of a First-Generation Clonal Seed Orchard of Chinese Pine (Pinus tabuliformis)

Abstract Seed orchards of Chinese pine, Pinus tabuliformis, are in a transition period from first generation to advanced generation. During this crucial period, evaluation of seed production in seed orchards is essential. Female strobili production is an important factor in seed production. This study examined the variation and stability in female strobili production in a first-generation clonal seed orchard of Chinese pine in years 9, 10, 13, 14, 20 and 21 after grafting in 1974. The results showed significant variation in female strobili production among clones, years, and interactions between clones and years. Correlations in female strobili production between years were significant. The repeatability for female strobili production within the examined years ranged from 0.47 to 0.87. The relative stability of female strobili production varied among clones, with regression coefficients among individual clones and an environmental index ranging from 0.13 to 2.81. The productivity index in different clones ranged from -1.09 to 1.83. Yield stability of female strobili among clones could be estimated from female strobili production. Clones could be divided into three groups according to their stability and productivity parameters. The results of this research provide guidance for evaluating clones in existing seed orchards, as well as some basic information for seed orchard management and advanced-generation seed orchard establishment.

Genetic selection of Calophyllum brasiliense for seed orchards

Calophyllum brasiliense populations are under severe depletion and criteria to improve production and quality of propagative material are therefore necessary. Genetic measures have the potential to reduce consanguinity and maximize allelic representation within target populations. Here, we explored genetic values for this species in a small relic of natural forest in Rio de Janeiro State (Brazil). The objective was to evaluate the potential of some genetic measures for seed orchard establishment. As genomic information of native trees is still scarce, we opted to use a dominant marker: RAPD. DNA from 17 phenotypically superior trees was obtained through the CTAB method and submitted for amplification by PCR. Electrophoresis and electronic documentation was then conducted. We calculated the percentage of polymorphic bands (PPB), gene diversity (Ht), Shannon’s information index (i), genetic distance (UPGMA) and parsimony analysis. Six primers were evaluated generating 34 loci. We found high genetic diversity PPB=70.6% with Ht=0.28 and i=0.41. Genetic relationships were reported in dendrograms (maximum parsimony and distance). Simulated sampling within and among clusters suggests that inter cluster sampling is more effective to capture the genetic diversity.

Variation in Floral Phenological Synchronization in a Clonal Seed Orchard of Pinus tabuliformis in Northeast of China

Abstract Flowering phenology in an orchard is a crucial factor affecting the gene exchange among clones and consequently changing genetic composition of the seed crop. Pinus tabuliformis is now at the crucial period from first generation clonal seed orchards to advanced generation seed orchards in China. In this study, variation and stability in floral phenological synchronization of all the clones and possible mating pairs, in terms of an index of phenological overlap, were observed in a first generation clonal seed orchard which located in northeast of China. Results showed that significant variations occurred in the clones and mating pairs. This kind of variation was apparently related with temperature and humidity of the research site. With increasing age, levels of flowering synchronization were likely to rise in the clones and mating pairs. In general, the average flowering synchronization of male parents was slightly higher than that of female parents, female management in a seed orchard should be paied more attention. Flowering time was under strong genetic control and this genetic control was stronger in the female flowering process than of the males in terms of board sense heritability and year to year correlation analysis. Flowering synchronization of female parents was positively correlated between most years and can be a reliable reference for early and late predication in Pinus tabuliformis seed orchard during stage of initial seed harvest to stable seed production. According to their average levels of flowering synchronization, 49 clones in the first generation clonal seed orchard were divided into 11 different groups. Results of this paper provided the basic information for first generation seed orchard management and advanced seed orchard establishment of Pinus tabuliformis.

Stability in and Correlation between Factors Influencing Genetic Quality of Seed Lots in Seed Orchard of Pinus tabuliformis Carr. over a 12-Year Span

Coniferous seed orchards require a long period from initial seed harvest to stable seed production. Differential reproductive success and asynchrony are among the main factors for orchard crops year-to-year variation in terms of parental gametic contribution and ultimately the genetic gain. It is fundamental in both making predictions about the genetic composition of the seed crop and decisions about orchard roguing and improved seed orchard establishment. In this paper, a primary Chinese pine seed orchard with 49 clones is investigated for stability, variation and correlation analysis of factors which influence genetic quality of the seed lots from initial seed harvest to the stable seed production over a 12 years span. Results indicated that the reproductive synchrony index of pollen shedding has shown to be higher than that of the strobili receptivity, and both can be drastically influenced by the ambient climate factors. Reproductive synchrony index of the clones has certain relative stability and it could be used as an indication of the seed orchard status during maturity stage; clones in the studied orchard have shown extreme differences in terms of the gametic and genetic contribution to the seed crop at the orchard's early production phase specifically when they severe as either female or male parents. Those differences are closely related to clonal sex tendency at the time of orchard's initial reproduction. Clonal gamete contribution as male and female parent often has a negative correlation. Clone utilization as pollen, seed or both pollen and seed donors should consider the role it would play in the seed crop; due to numerous factors influencing on the mating system in seed orchards, clonal genetic contribution as male parent is uncertain, and it has major influence on the genetic composition in the seed orchard during the initial reproductive and seed production phase.

Another CAPS DNA marker for sex identification in jojoba seedlings

Jojoba [Simmondsia chinensis (Link) Schneider] plant has immense industrial value. Jojoba is grown for its seed oil, which is a unique liquid wax consisting of esters formed from acids and alcohols with chain lengths of 20 or 22 carbon atoms. Higher seed yield is obtained when well balanced male and female plants are established in jojoba orchard. However, the sex of jojoba plants cannot be determined with morphological characters until the plants reach reproductive maturity. DNA markers are commonly used for plant genetic studies [1,2,3,4], Up-to-date several male and female specific DNA markers have been developed for sex identification in jojoba seedlings [5,6]. This study reports another cleavage-amplified polymorphic sequence (CAPS) assay, which easily identify male individuals. Genomic DNAs of 16 male and 16 female jojoba plants growing in an orchard were extracted using a DNA extraction protocol [4]. A touch-down PCR approach was used to amplify genomic DNAs of jojoba using J818F 5'-AGGGGATAAATGAGCCGAAT-3' and J818R 5'-GACCCAGAGGATGAGGAATG-3' primer pair [6]. Amplified products were digested using Hind III restriction enzyme. Electrophoresis separation of the digested products as shown in Figure 1 indicated that male and female jojoba plant can be easily identified. CAPS marker reported in this study could be used in breeding studies and in the sex allocation of seedlings in seed orchard establishment.

Early determination of sex in jojoba plant by CAPS assay

SUMMARYJojoba [Simmondsia chinensis (Link) Schneider] is a dioecious plant grown for its seeds, which are the source of liquid wax or jojoba oil. The sex of jojoba plants cannot be determined with morphological characters until the plants reach reproductive maturity at 3 or more years old. This difficulty of early sex determination imposes severe constraints in breeding studies and in the sex allocation of seedlings in seed orchard establishment, and importantly in a priori mating designs to produce superior jojoba individuals. This study reports three new cleavage-amplified polymorphic sequence (CAPS) assays, which identify male and female individuals distinctly. One of the assays could also identify hermaphrodite jojoba plants existing in nature or obtained using mutagenesis studies.

Genetic Variation in Early Growth Characteristics of Two Populations of Wild Service Tree (Sorbus torminalis (L.) Crantz) and Their Interrelationship

AbstractThis study was performed in order to compare two wild service tree populations (Sorbus torminalis (L.) Crantz) for their early growth and to find useful vegetative characteristics to be used in indirect selection of fast and tall growing trees of the species in the field. We used phenotypic and genotypic correlation coefficients estimated on data from 30 three-year old seedlings of each 40 randomly selected adult trees. Assuming genetic differences between the trees sampled, path analysis was performed on genotypic and phenotypic levels. Results showed that plus trees of one of the sites may be used for clonal seed orchard establishment. But the other site is suggested as a better site for breeding purposes with more effective Sorbus population. Collar diameter had the strongest positive direct effect and strongest correlation with plant height at the phenotypic level. In contrast, lateral branches showed very weak direct effect but relatively strong total indirect effect on plant height. Path analysis on the genotypic correlation coefficients detected negative indirect effect between the characters. Collar diameter could be regarded as a good predictor of plant height because of its strong direct and indirect phenotypic and genotypic correlations. The use of recommended selection criteria is discussed.

Ten-year results from red alder (Alnus rubra Bong.) provenance-progeny testing and their implications for genetic improvement

Ten-year data on growth and survival of two red alder provenance-progeny test trials located in the southern and northern coastal regions in British Columbia, Canada, were analysed and their implications for the genetic improvement of this species were discussed. A total of 42 and 41 provenances, each represented by two to five open-pollinated families were evaluated at each site, respectively. Results indicate that red alder provenances responded differently to the environmental conditions of the two sites. At age 10, red alder provenances tended to perform better at sites near their origin. The results support earlier work that two breeding zones should be delineated with the boundary at approximately 52° N. One may expect an average of about 5% decrease in stem volume and 6% increase in mortality, respectively, for each degree of southward and northward transfer of seed sources from their origins. Individual, family, and within-family heritabilities for height, diameter, stem volume were moderately high (0.22–0.42), for the southern zone, implying good potential for genetic improvement. Heritabilities were somewhat lower (0.12–0.39) for the northern zone because of greater environmental heterogeneity of the test site. Selecting the top 20 unrelated individuals for seed orchard establishment would result in 29% and 23% gain in stem volume at a rotation age of 40 years in the southern and northern zones, respectively. Correlation between ranks of the predicted breeding values for height at different ages and stem volume at age 10 increased rapidly when plantation was young and became relatively stable after 6 years of out-planting. Stem volume had much stronger correlation with diameter (≥0.84) than with height (≤0.67). Early selection at age 6 based on stem volume is therefore recommended.

Advanced generation seed orchards’ turnover as affected by breeding advance, time to sexual maturity and costs, with special reference to Pinus sylvestris in Sweden

The effect of various biological, genetic, economic and management factors relevant to advanced generation seed orchard establishment was investigated using numerical estimates for Scots pine (Pinus sylvestris L.) in Sweden. Factors considered were planting density, rate of genetic advance in the breeding population, timing of first seed collection, seed value, seed production cost (stratified to establishment, annual management, cone harvest and seed extraction), orchard rotation age and contamination level. The developed model demonstrated its utility in studying and evaluating various economic and biological options associated with advanced generation seed orchard establishment/turnover. Sensitivity analyses demonstrated the robustness of the developed model through various arbitrarily changes in genetic gain advances, establishment, management and seed production, particularly those associated with cone harvests from upper crown and costs. The Swedish Scots pine case study produced results supporting faster turnover of seed orchard generations (30 vs 40 years) with shorter orchard lifespan (early start of seed cone after 8 years vs 15 years) delivering higher gain through minimizing the genetic gain differential between the breeding and production populations and allowing the capture of this gain for inclusion in the seed orchards. Orchard planting densities of 400 and 600 grafts per hectare produced similar results with marginal differences, and the latter was recommended for future orchard establishment.

Pinus roxburghii: Standardization of Grafting Techniques for Establishment of Clonal Seed Orchards

Pinus roxburghii Sargent (Chir pine) is one of the important species among the six Himalayan pines. Like other forest species, Chir pine is a wind-pollinated conifer characterized by a considerable variation. Since clonal multiplication through grafting is one of the best techniques to provide viable, improved propagating stocks in large quantities for further utilization in clonal seed orchards for the production of superior seed. Keeping in view the importance of chir pine for the lower Himalayan areas, work on standardization of grafting technique was undertaken. Various grafting techniques were employed to achieve high grafting rate. A success of 29.55 per cent under partial shade and 46.79 per cent in open conditions have been achieved through top bud cleft grafting.

Predicting individual breeding values and making forward selections from open-pollinated progeny test trials for seed orchard establishment of interior Lodgepole Pine (Pinus contorta ssp. latifolia) in British Columbia

Ten-year height data from three open-pollinated lodgepole pine progeny test trials were analysed in order to select individuals for seed orchard establishment in the low and high elevation seed-planning units (TOLO and TOHI) of the new Thompson Okanagan seed planning-zone in interior British Columbia, Canada. The total test population had about 35,000 individuals from 362 families of 9 provenances and was divided into two portions, each serving as the base population for its appropriate seed-planning unit. For each population, various genetic parameters were estimated and individual breeding values were predicted. Combined-site estimates of individual, family, and within-family heritability ranged from 0.23 to 0.38, 0.77 to 0.84, and 0.17 to 0.29, respectively. Estimated coefficients of type-b genetic correlation were greater than 0.81, indicating little G × E interaction in this region. Provenance effects were large. Larch Hills and Inonoaklin River were the two superior provenances with an expected gain of 13% and 10% in stem volume at rotation age of 60 years in TOLO. Individual breeding values was not uniformly distributed among provenances and the top 100 individuals originated from 20 families in TOLO and 32 families in TOHI. Co-ancestry among these individuals should not be a serious concern in seed orchard establishment as the predicted genetic loss due to excessive inbreeding is only 1.06% in TOLO and 0.6% in TOHI. The status numbers of the two prospective seed orchards are 32 and 44, respectively, and both are well above the required minimum of 10 in British Columbia. Using unrelated clones for seed orchard establishment may result in reduced optimum genetic gain and thus is not a favourable option.

Genetic variation in resistance to Dreyfusia nordmannianae Eckst. infestations in Abies nordmanniana (Stev.) Spach.

Nordmann fir ( Abies nordmanniana (Stev.) Spach.) is the main tree species for Christmas tree production in Denmark and adelgid attack is a severe problem. Genetic differences between Nordmann fir provenances, families within provenances and their suitability as host plants for the silver fir woolly adelgid ( Dreyfusia nordmannianae Eckst.) were investigated based on artificial infestations of 63 families originating from three provenances and four provenance samples a total of 2100 seedlings planted in a single field trial. Counts of adelgids, curling of needles due to adelgid attack together with flushing and several growth traits were measured in each tree for 2 consecutive years. The artificial infestation was very efficient, with 97% of the trees infested. Family mean infestation levels ranged from 69.5 to 100% for sistentes in the first year. Very pronounced and significant family differences were seen after the year 2 assessments. Estimated heritabilities, and genetic variation among families showed a much lower level for the adelgid counts than for flushing and growth traits. Strong differences in needle curling were seen for the same infestation levels of adelgids, indicating differences in tolerance among families. Traditional backwards selection based on family means and seed orchard establishment with moderate selection intensities can reduce the future damage level but not eliminate the adelgid problem.

Feasibility of seed orchard establishment, rogueing and lifespan

Apart from genetic gains, the feasibility of seed orchards is influenced by cost factors, management decisions and rates of propagation. The authors investigate the establishment, rogueing and lifespan of seed orchards, with emphasis on investment and operating costs, optimal assessment age and expected seed yields. Expenditures for establishment of seed orchards are compared to present values of savings on reduced regeneration areas, due to gains from improved stock. Lambeth's selection efficiency and age correlation formulae are used for optimizing the timing of rogueing. For the decision as to the economic lifespan of the seed orchards, the costs of investment and operation were distributed over the cone yield produced. The case studies presented refer to operational conditions in Canada and Europe.

Production of Radiata Pine Cuttings for Seed Orchard Establishment

SUMMARY Since grafted stock may develop incompatibility symptoms it is preferable to use rooted cuttings for establishment of clonal seed orchards of Pinns radiata. Details of the propagating bed system and cultural procedures used for propagating mature clones in Gippsland, Victoria are described. Cuttings were taken from grafted ramets of clones whose ortets were between 20 and 89 years old. Of 5,000 cuttings set in 1974, 63 per cent produced plantable stock after 12 months. The proportion produced by different clones varied from 15 to 91 per cent and part of this variation was ascribed to a negative relationship with ortet age. Comparison of production data over a three year period showed that clonal differences were repeatable (mean r2 = 0.48) and so data from an initial setting can be used to adjust numbers for subsequent settings of the same clone. Production cost of each plantable cutting was estimated to be $0.88 in 1974/75.

THE VEGETATIVE PROPAGATION OF EUCALYPTUS—AN ACCOUNT OF PROGRESS

SUMMARY Vegetative propagation of Eucalyptus has been achieved in several different ways, mainly by grafting, but air-layers have also been successful and cuttings will also root if sections cut from stems of very young seedlings are used. Current techniques are adequate for seed orchard establishment, horticultural use, and experiment, but further development is necessary to prescribe methods cheap enough for the production of general planting stock.