Journal articles on the topic 'Tree improvement (incl. selection and breeding)'
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1
Lebedev, Vadim G., Tatyana N. Lebedeva, Aleksey I. Chernodubov, and Konstantin A. Shestibratov. "Genomic Selection for Forest Tree Improvement: Methods, Achievements and Perspectives." Forests 11, no. 11 (November 11, 2020): 1190. http://dx.doi.org/10.3390/f11111190.
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The breeding of forest trees is only a few decades old, and is a much more complicated, longer, and expensive endeavor than the breeding of agricultural crops. One breeding cycle for forest trees can take 20–30 years. Recent advances in genomics and molecular biology have revolutionized traditional plant breeding based on visual phenotype assessment: the development of different types of molecular markers has made genotype selection possible. Marker-assisted breeding can significantly accelerate the breeding process, but this method has not been shown to be effective for selection of complex traits on forest trees. This new method of genomic selection is based on the analysis of all effects of quantitative trait loci (QTLs) using a large number of molecular markers distributed throughout the genome, which makes it possible to assess the genomic estimated breeding value (GEBV) of an individual. This approach is expected to be much more efficient for forest tree improvement than traditional breeding. Here, we review the current state of the art in the application of genomic selection in forest tree breeding and discuss different methods of genotyping and phenotyping. We also compare the accuracies of genomic prediction models and highlight the importance of a prior cost-benefit analysis before implementing genomic selection. Perspectives for the further development of this approach in forest breeding are also discussed: expanding the range of species and the list of valuable traits, the application of high-throughput phenotyping methods, and the possibility of using epigenetic variance to improve of forest trees.
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Norton, J. D., Hongwen Huang, and Fenny Dane. "Breeding and Improvement of Chinese Chestnut." HortScience 33, no. 4 (July 1998): 600f—600. http://dx.doi.org/10.21273/hortsci.33.4.600f.
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The Chinese chestnut (Castanea mollissima Blume) is a valuable germplasm resource for horticultural traits such as resistance to chestnut blight (Cryphonectria parasitica), excellent quality, wide adaptation, and consistent high yield. The Chinese chestnut breeding program was established at Auburn Univ. in 1933 from nuts directly introduced from China by the USDA. A recurrent selection breeding program with progeny from the 1933, 1953, and 1991 plantings with selection for blight resistance, precocity, nut size, and storage quality, yield, and pest resistance. Cultivars released from the 1933 planting were `Alaling,' `Alamore', and `Black Beauty'. `AU-Cropper', `AU-Leader', and `AU-Homestead' were named from the 1953 planting. Two blight-resistant, precocious seedlings, AU-91-P1-26 and AU-P4-26, appear to be very promising selections for improvement of all Chinese chestnut cultivars for nut size and other selection traits. Since there is little information available regarding heritability of certain traits in perennial tree species, results of 65 years of breeding at Auburn Univ. should provide us with guidance for further improvement of selection traits in chestnut breeding.
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Cheliak, W. M., and D. L. Rogers. "Integrating biotechnology into tree improvement programs." Canadian Journal of Forest Research 20, no. 4 (April 1, 1990): 452–63. http://dx.doi.org/10.1139/x90-062.
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Time is a major constraint in the progress of tree improvement programs. Four ways in which time influences the tree improvement process are (i) evolutionary time, (ii) time to harvest, (iii) time to achieve phenotypic stability, and (iv) time to reach reproductive maturity. The ways in which each of these affects the three phases of a tree improvement program (conservation, selection and breeding, and propagation) are identified and discussed. How biotechnological techniques, as well as other enabling technologies, address the time constraint problem is also discussed. The biotechnological approaches include tissue culture, molecular genetics, and genetic engineering; the enabling technologies include early testing and flower induction. Through tissue culture it is possible to increase genetic gain per unit time and increase total genetic gain by using more of the total genetic variation. Development of high-resolution linkage maps, through application of molecular genetics technology, will provide new approaches to early screening, testing, and selection. Additionally, molecular probes will be useful in improving methods that genetically fingerprint germ plasm. Genetic engineering has considerable potential to reduce time constraints. However, because of the diverse breeding and production populations typically employed, much basic work needs to be done to integrate genetically engineered materials into tree improvement programs. Early selection and flower induction address the time constraints imposed by age-stable performance and reproductive maturity. When used in combination with the previously described biotechnologies, a powerful system is created that can dramatically reduce the time required to integrate genetically improved material into forest regeneration programs. An example of integrating tree improvement, clonal forestry, and biotechnology is described for an existing black spruce regeneration program.
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Mahajan, R., and P. Gupta. " Molecular markers: their use in tree improvement." Journal of Forest Science 58, No. 3 (March 27, 2012): 137–44. http://dx.doi.org/10.17221/5579-jfs.
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Earlier breeders used phenotypic selection based on morphological characteristics to improve tree varieties. These selections often take many cycles of breeding and backcrossing in order to place desired characteristics. But today the knowledge has paved the way for a much deeper understanding of the mechanics of cell biology and the hereditary process itself. Breeders are presented with numerous possibilities of altering the behaviour of existing varieties. Linkage between molecular markers can be translated to genetic linkage maps, which have become an important tool in plant genetics. They may choose to use marker-assisted approaches in order to facilitate the selection of favourable combinations of genes that occur naturally within a tree species.
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Huang, Yinghua, David Karnosky, and C. G. Tauer. "Applications of Biotechnology and Molecular Genetics to Tree Improvement." Arboriculture & Urban Forestry 19, no. 2 (March 1, 1993): 84–98. http://dx.doi.org/10.48044/jauf.1993.016.
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Biotechnology, which has made significant contributions to the improvement programs of agronomic crops, offers the opportunities to enhance forestry research and accelerate tree improvement. Forest biologists and tree breeders are turning their attentions to these biotechnologies, which enable them to overcome barriers and can be integrated into conventional breeding methods leading to more rapid progress in tree breeding. Plant biotechnology currently comprises a range of activities, such as vegetative propagation and tissue culture, genome analysis and gene cloning, DNA recombination and gene transfer, and DNA-based selection. Although application of biotechnology in forest trees and ornamental woody plants is just in its infancy, micropropagation is rapidly becoming a standard tool for tree improvement. In addition, emerging success and practical application have become visible in genetic transformation. These initial achievements have already proven that biotechnology will make inestimable impact on tree improvement.
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Zhao, Ye, Yanting Tian, Yuhan Sun, and Yun Li. "The Development of Forest Genetic Breeding and the Application of Genome Selection and CRISPR/Cas9 in Forest Breeding." Forests 13, no. 12 (December 10, 2022): 2116. http://dx.doi.org/10.3390/f13122116.
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With the birth of classical genetics, forest genetic breeding has laid a foundation in the formation of the basic theories of population genetics, quantitative genetics, cytogenetics, and molecular genetics. Driven by the rapid growth of social demand for wood and other forest products, modern genetics, biotechnology, biostatistics, crop and animal husbandry breeding theories, and technical achievements have been continuously introduced for innovation, thus forming a close combination of genetic basic research and breeding practice. Forest tree breeding research in the world has a history of more than 200 years. By the middle of the 20th century, the forest tree genetic breeding system was gradually formed. After entering the 21st century, the in-depth development stage of molecular design breeding was opened. With the continuous improvement of traditional genetic breeding methods, emerging modern bioengineering technology has also continuously promoted the development of forest genetic breeding. This study mainly summarizes the research history of forest tree genetics and breeding, as well as discusses the application of modern bioengineering technology represented by genome selection and gene editing in forest tree breeding, so as to provide better reference for forest tree breeding research.
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El-KASSABY, YOUSRY A., and MILAN LSTIBŮREK. "Breeding without breeding." Genetics Research 91, no. 2 (April 2009): 111–20. http://dx.doi.org/10.1017/s001667230900007x.
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SummaryAn innovative approach to tree breeding called ‘breeding without breeding’ (BWB) is presented. The method, as applied on the material in hand, allows the capture of 75–85% of the genetic response to selection attained through conventional programmes without the need to do any controlled pollination and simplified or possibly no experimental field testing: both considered to be the most resource-demanding activities in breeding programmes. BWB combines the use of genotypic or phenotypic pre-selection of superior individuals, informative DNA markers for fingerprinting and pedigree reconstruction of offspring to assemble naturally created full- and half-sib families resulting from mating among selected parents, and quantitative genetics analyses to identify elite genotypes for further genetic improvement or the establishment of production populations. BWB utility is demonstrated using a retrospective study of Douglas-fir (Pseudotsuga menziesii) progeny tests consisting of offspring produced from 150 controlled crosses among 60 parents and established over three sites. The empirical results are supported by theoretical expectations demonstrating anticipated minimum genetic response compared with conventional approaches. The method's simplicity offers an exceptional opportunity for the development of comparable breeding efforts in developing countries, advanced and new breeding programmes, and economically important and ‘minor’ species.
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Faulkner, Roy. "Genetics and breeding of Sitka spruce." Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences 93, no. 1-2 (1987): 41–50. http://dx.doi.org/10.1017/s0269727000006266.
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SynopsisSitka spruce is a monoecious, wind-pollinated, cross-fertilising species showing wide genetic variation which suggests heterozygosity for many alleles and natural selection against self-fertilisation. Phenotypic selection for the important trait of vigour is ineffective, so testing progenies of selected individuals and clonal testing is an essential and time-consuming part of any improvement programme. Old trees can be vegetatively propagated by grafting and very young trees by rooted cuttings.The British tree improvement programme is based, in the short term, on the use of seed collected from superior plantation trees of desirable origins; in the mid term on seed derived from clonal orchards based on mixtures of clones previously tested for superiority in family tests; and in the longer term on highly superior seed or clones derived from a system of recurrent mating with family selection. Three populations are being developed. There is a small interspecific hybridisation programme.
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Thakur, Ram Bichari, and Joachim Schmerbeck. "Role of Tree Breeding in Timber and Wood Supply in World and India: Status and Outlook." Initiation 5 (April 19, 2014): 153–63. http://dx.doi.org/10.3126/init.v5i0.10266.
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Tree breeding is an important component of tree improvement which involves the application of genetic principles for the mass production of seedlings with desired traits in order to achieve higher productivity, better adaptability of the environment and vigorous growth rate. It helps in increasing yields and shortened rotations so it has a large potentiality to supply timber and wood demand of the world. Species choice, provenance selection and propagation method are the major aspects of tree breeding. Plus tree selection, progeny testing, provenance test and vegetative propagation have been used since early of civilization and often regarded as conventional tree breeding techniques while seed orchards, clonal propagation, somatic embryogenesis, micro-propagation or in-Vitro propagation, and biotechnology are modern tree breeding techniques. Different countries have been developing tree breeding techniques and achieving maximum benefits from it. Southeast Asia is using Acacia mangium, A. crassicarpa, Gmelina arborea, and Eucalyptus spp.; Populus deltoids, Casuarina equisetifolia, Eucalyptus spp. have been using by India; Teak has been vegetative propagated in Thailand; Salix babylonica has been growing in Greece for biomass production. Increasing yield and shortened rotation are the major prospects while loss of genetic diversity, higher production costs and requirement of constant upgrading are the major hindrances of tree breeding. DOI: http://dx.doi.org/10.3126/init.v5i0.10266 The Initiation 2013 Vol.5; 153-163
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Parnia, P., Gh Mladin, I. Duţu, and N. Stanchi. "Progress in Breeding Rootstocks in Romania." HortScience 23, no. 1 (February 1988): 107–9. http://dx.doi.org/10.21273/hortsci.23.1.107.
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Abstract For the past 10 years, new attention has been given in Romania to the development of improved fruit tree rootstocks by hybridization and mutation breeding. Prior to 1976, rootstock improvement was focused primarily on selection in seedling populations derived from both wild and cultivated forms, with emphasis on adaptation to local soil and climatic conditions. The rootstocks now in commercial use in Romania come from these sources.
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Lindgren, Dag, Darius Danusevičius, and Ola Rosvall. "Balanced forest tree improvement can be enhanced by selecting among many parents but maintaining balance among grandparents." Canadian Journal of Forest Research 38, no. 11 (November 2008): 2797–803. http://dx.doi.org/10.1139/x08-114.
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A model for a balanced tree breeding program that considers genetic gain and cost was used to assess the benefits of increasing the breeding population to allow for a component of among-parent selection while maintaining an equal contribution among grandparents, rather than relaying on within-family selection with an equal parental representation. The scenario used in this study had characteristics similar to those of the phenotypic selection strategy for Scots pine ( Pinus sylvestris L.) in Sweden. The results showed that investments in a greater number of parents and families to allow for among-parent selection resulted in a markedly higher genetic gain. The among-parent selection component increased the genetic gain by as much as 70% in a scenario with a high budget and no family creation costs and by as much as 20% in a scenario with a low budget and high family creation costs.
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Berguson, W. E., B. G. McMahon, and D. E. Riemenschneider. "Additive and Non-Additive Genetic Variances for Tree Growth in Several Hybrid Poplar Populations and Implications Regarding Breeding Strategy." Silvae Genetica 66, no. 1 (December 28, 2017): 33–39. http://dx.doi.org/10.1515/sg-2017-0005.
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Abstract Populus species (P. deltoides, P. maximowiczii, P. nigra) and their inter-specific hybrids were tested for growth rate over a five year period at four test locations in Minnesota, USA, to estimate genetic variance components. The breeding scheme incorporated recurrent selection of full-sib families of pure species parents, production of F1 inter-specific hybrids from selected families, and selection of clones within the F1s. Improvement of yield through time using this scheme is predicated on the assumption that additive effects comprise a significant portion of the total genetic variance. The estimates of additive and non-additive variances reported are not traditional point estimates, because a fully balanced mating design was impossible due to parental incompatibilities which result in incomplete breeding matrices. Instead, bounded estimates, not previously used in tree genetics research, are derived from linear combinations of formulae of genetic expectations observed among-family, among-clone, and environmental variances. Our results suggest that combined family and mass selection would lead to increases in growth rate of 27 % and 47 % per generation in P. deltoides and P. nigra, respectively. Broad sense-based clonal selection within the F1 could yield selection responses in excess of 90 % of the mean of such populations. Among-family variance comprised about 1/3 of total genetic variance while within-family variance was always about 2/3 of total genetic variance, regardless of pedigree. The results indicate that recurrent intraspecific selective breeding followed by interspecific hybridization and non-recurrent selection based on broad sense genetic variation would constitute an effective yield improvement strategy.
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Perron, M. "A Strategy for the Second Breeding Cycle of Larix x marschlinsii in Québec, Canada Including Experiments to Guide Interspecific Tree Breeding Programme." Silvae Genetica 57, no. 1-6 (December 1, 2008): 282–91. http://dx.doi.org/10.1515/sg-2008-0043.
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AbstractA strategy for the genetic improvement of Larix decidua P. Mill., L. kaempferi (Lamb.) Carrière and their hybrid (L. x marschlinsii Coaz) in Québec, Canada, was set up to provide short and long-term genetic gains, as well as basic populations for some fundamental experiments. A reciprocal recurrent selection with forward selection strategy (RRS-FS) will be applied by using a pollen mix breeding with a partial population paternity analysis (PMX/WPPA). The genetic mechanisms responsible for heterosis among trees remain poorly understood. This complicates the implementation of multi-species genetic improvement programmes seeking to achieve the full benefits of interspecific hybridization. Various strategies to exploit heterosis are outlined. To expand our knowledge and guide our future choices, basic research has been integrated directly into breeding and testing activities, as well as through experiments integrated within activities leading to recommendations about the top-ranked families to be used in reforestation (cuttings). These experiments can also serve as the basis for future studies seeking a better understanding of heterosis through molecular genetics.
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Grattapaglia, Dario. "Twelve Years into Genomic Selection in Forest Trees: Climbing the Slope of Enlightenment of Marker Assisted Tree Breeding." Forests 13, no. 10 (September 23, 2022): 1554. http://dx.doi.org/10.3390/f13101554.
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Twelve years have passed since the early outlooks of applying genomic selection (GS) to forest tree breeding, initially based on deterministic simulations, soon followed by empirical reports. Given its solid projections for causing a paradigm shift in tree breeding practice in the years to come, GS went from a hot, somewhat hyped, topic to a fast-moving area of applied research and operational implementation worldwide. The hype cycle curve of emerging technologies introduced by Gartner Inc. in 1995, models the path a technology takes in terms of expectations of its value through time. Starting with a sudden and excessively positive “peak of inflated expectations” at its introduction, a technology that survives the “valley of disappointment” moves into maturity to climb the “slope of enlightenment”, to eventually reach the “plateau of productivity”. Following the pioneering steps of GS in animal breeding, we have surpassed the initial phases of the Gartner hype cycle and we are now climbing the slope of enlightenment towards a wide application of GS in forest tree breeding. By merging modern high-throughput DNA typing, time-proven quantitative genetics and mixed-model analysis, GS moved the focus away from the questionable concept of dissecting a complex, polygenic trait in its individual components for breeding advancement. Instead of trying to find the needle in a haystack, i.e., the “magic” gene in the complex and fluid genome, GS more efficiently and humbly “buys the whole haystack” of genomic effects to predict complex phenotypes, similarly to an exchange-traded fund that more efficiently “buys the whole market”. Tens of studies have now been published in forest trees showing that GS matches or surpasses the performance of phenotypic selection for growth and wood properties traits, enhancing the rate of genetic gain per unit time by increasing selection intensity, radically reducing generation interval and improving the accuracy of breeding values. Breeder-friendly and cost-effective SNP (single nucleotide polymorphism) genotyping platforms are now available for all mainstream plantation forest trees, but methods based on low-pass whole genome sequencing with imputation might further reduce genotyping costs. In this perspective, I provide answers to why GS will soon become the most efficient and effective way to carry out advanced tree breeding, and outline a simple pilot demonstration project that tree breeders can propose in their organization. While the fundamental properties of GS in tree breeding are now solidly established, strategic, logistics and financial aspects for the optimized adoption of GS are now the focus of attentions towards the plateau of productivity in the cycle, when this new breeding method will become fully established into routine tree improvement.
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Wei, R. P., and D. Lindgren. "Optimum breeding generation interval considering buildup of relatedness." Canadian Journal of Forest Research 31, no. 4 (April 1, 2001): 722–29. http://dx.doi.org/10.1139/x00-198.
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Models taking genetic gain, relatedness, delay at generation turnover, and breeding population size into account have been developed to optimize selection age and generation interval. Relatedness (expressed as group coancestry) and average breeding value for the breeding population are merged into a joint index ("group merit"). The negative impact of group coancestry (like potential inbreeding depression) is expressed in a scale compatible with breeding value. Group merit measures the desirable characteristic of a breeding population. Annual increase of group merit is the criterion for comparing alternatives. Optimum generation interval is when annual group merit increase is highest. Generally the optimum selection age becomes higher when increase in relatedness is considered. We quantify the influence of relatedness penalty, early-mature genetic correlation, breeding population size, and delay at generation turnover on optimum selection age. A reasonable large population counteracts the increase of relatedness and, thus, favors early selection. Early selection can have a negative impact if a small early selection gain does not compensate for the buildup of relatedness at generation turnover. Conditions for this to occur are quantified. Early selection requires sufficient high juvenile-mature correlation to have a positive effect; this requirement can be reduced by using a large breeding population. The methods developed were applied to a number of situations relevant to forest tree improvement.
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Blackburn, David, Ross Farrell, Matthew Hamilton, Peter Volker, Chris Harwood, Dean Williams, and Brad Potts. "Genetic improvement for pulpwood and peeled veneer in Eucalyptus nitens." Canadian Journal of Forest Research 42, no. 9 (September 2012): 1724–32. http://dx.doi.org/10.1139/x2012-105.
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Genetic improvement of wood properties affecting the quality of pulpwood and peeled veneer products is of general interest to tree breeders worldwide. If the wood properties of Eucalyptus nitens (H. Deane & Maiden) Maiden are under genetic control and the correlations between them are favourable, it may be possible to breed to simultaneously improve the plantation resource for both products. Acoustic wave velocity (AWV) measured in standing trees can predict wood stiffness, basic density, and kraft pulp yield (KPY) and therefore has the potential for use in tree breeding programs. From an E. nitens progeny trial in Tasmania, 540 trees were selected for rotary peeling. Of the wood properties assessed, there were significant differences among races in diameter, stem straightness, standing-tree, log, and billet AWV, and near infrared predicted cellulose content (CC). All traits displayed significant within-race genetic variation, and genetic correlations between AWV and veneer sheet modulus of elasticity (MOE) and between AWV and KPY and CC were strongly positive and highly significant. A similar relationship was found between veneer sheet MOE and KPY and between diameter at breast height and veneer sheet MOE. Basic density was genetically correlated with AWV and veneer sheet MOE. Results indicate that it should be possible for breeders to simultaneously improve properties in pulpwood and peeled veneer products and that AWV measured in the standing tree shows promise as a breeding selection criterion for both pulpwood and peeled veneer products.
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Weng, Y. H., P. Lu, Q. F. Meng, and M. Krasowski. "Genetic resistance to western gall rust in jack pine and its relationship with tree height growth." Canadian Journal of Forest Research 45, no. 8 (August 2015): 970–77. http://dx.doi.org/10.1139/cjfr-2014-0535.
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Developing resistance to western gall rust (WGR) is important for maintaining healthy and productive jack pine plantations. In this study, we estimated genetic parameters of resistance to WGR and its relationship with tree height growth, based on data collected from three second-generation full-sib progeny testing series of jack pine planted in New Brunswick, Canada. Results indicated that (i) resistance to WGR in jack pine was controlled by both additive and dominance gene effects, with the latter playing a greater role; (ii) narrow-sense heritability estimates for resistance to WGR were low (mean = 0.05; series range = 0.00∼0.09), and broad-sense heritability estimates were moderate on an individual-tree basis (mean = 0.53) and considerably higher on the full-sib family mean basis (mean = 0.87); (iii) additive genetic correlation between tree height growth and WGR incidence was low (≤0.06) in two series and only slightly higher and favorable (–0.19) in one series, suggesting that selection on growth traits would not negatively affect WGR resistance; and (iv) mid-parental additive genetic and dominance effects on WGR were empirically correlated (>0.65), indicating that incorporating breeding for WGR resistance into current jack pine tree improvement programs with a seed orchard approach could partly capture the benefit from dominance effects. Although genetic gains in WGR resistance could be realized through various breeding and deployment schemes, it appeared that rapid improvement could be achieved through backward selection on full-sib family means.
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Gonçalves, Paulo de Souza, Adriano Tosoni da Eira Aguiar, Reginaldo Brito da Costa, Elaine Cristine Piffer Gonçalves, Erivaldo José Scaloppi Júnior, and Roberto Botelho Ferraz Branco. "Genetic variation and realized genetic gain from rubber tree improvement." Scientia Agricola 66, no. 1 (February 2009): 44–51. http://dx.doi.org/10.1590/s0103-90162009000100006.
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Breeding cycle in rubber extends to 20-30 years between pollination and yield assessment, distributed over three selection stages. Five hectares of small scale trial of rubber tree [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell.-Arg.], was established in the Northwestern region of São Paulo State, Brazil. The population comprises 98 clones mostly derived from intensively selected plus tree in the natural forest of rubber tree in the Amazon. Three open pollinated progeny tests were established in three experimental stations. Seedlings from 98 progenies including a commercial check (CC) were planted in each one of the three locations. Assessments were made when the plants were one, two and three years old. The variation among progenies for girth was highly significant in all locations examined. In the combined analysis of variance over three locations, differences among progenies were also detected, while progeny × location interaction effect was not significant. Narrow sense heritability estimates on individual tree basis (h i²) were variable depending on the characteristic, age of assessment and experimental location. Realized genetic gains were calculated for the plant characteristics at the age of three years, by comparing the performance of improved (selected) materials to unimproved materials (CC). The total genetic gain from the genetically tested first generation clone population at Votuporanga is estimated as 25% for girth, 14% for rubber yield and 25% for bark thickness. Improvement of rubber tree by selection, establishment of clonal population (isolated garden) and progeny testing is a very promising and profitable operation.
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Neale, David B., and Claire G. Williams. "Restriction fragment length polymorphism mapping in conifers and applications to forest genetics and tree improvement." Canadian Journal of Forest Research 21, no. 5 (May 1, 1991): 545–54. http://dx.doi.org/10.1139/x91-076.
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It is now technically possible to construct high-density restriction fragment length polymorphism maps for almost any conifer. Hundreds of new genetic markers will become available for forest genetics research and tree-improvement applications. Having a large number of genetic markers will improve efficiency in studies in which isozymes or other markers have traditionally been applied (e.g., genetic variation in populations, paternity analysis, varietal identification, and seed-orchard efficiency). High-density restriction fragment length polymorphism maps may make it possible to (i) identify quantitative trait loci and (ii) practice marker-assisted selection in conifer breeding.
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Wolyn, David J., and Gregory Innes. "Eight cycles of half-sib family recurrent selection to improve rubber yield in Russian dandelion." Canadian Journal of Plant Science 102, no. 2 (April 1, 2022): 368–74. http://dx.doi.org/10.1139/cjps-2021-0134.
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Russian dandelion (Taraxacum kok-saghyz) produces natural rubber which can complement the world’s supply of this strategic commodity, derived mainly from the Para rubber tree (Hevea brasiliensis). Four cycles of half-sib family recurrent selection conducted previously in Russian dandelion improved rubber yield nearly 50%. The objectives of this research were to continue selection for four additional cycles and evaluate progress from eight generations of breeding, and assess the potential for future gains. Rubber yield increased from 0.205 to 0.378 g/plant from Cycle 0 (C0) to C8, representing an 84% improvement, or 10% per cycle. Increases from C0 to C4 were similar to those from C4 to C8. Root dry weight did not increase from selection and improved yield only resulted from enhancing rubber percentage which changed from 4.35% to 7.62%. Selection response has not plateaued, and phenotypic variation has not decreased, indicating continued gains can occur with additional breeding.
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Hardner, Craig, João Costa e Silva, Emlyn Williams, Noel Meyers, and Cameron McConchie. "Breeding New Cultivars for the Australian Macadamia Industry." HortScience 54, no. 4 (April 2019): 621–28. http://dx.doi.org/10.21273/hortsci13286-18.
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In 2017, five new cultivars specifically selected for Australian conditions were released. These were developed from an improvement program initiated by Commonwealth Scientific and Industrial Research Organisation in the early 1990s. Progeny seeds were produced by crossing industry standard cultivars with other cultivars with elite kernel production per unit projected canopy area. Seedlings were planted at two densities (2 m and 4 m along rows) in field trials at Bundaberg in 1997 and 1998, and Northern New South Wales in late 1997, along with replicated plants of parents grafted onto seedling rootstocks. Trials were assessed for commencement of flowering, growth, yield, kernel recovery, and components of kernel quality over 8 years. Best linear unbiased predictions of clonal values were obtained for each individual progeny using a pedigree-based mixed linear model. A bio-economic model was used to estimate economic weights for a selection index of clonal values to identify elite candidates. Final approval of 20 candidates for second-stage assessment was made by an industry committee using selection index rankings and observations of tree field performance and kernel quality.
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Varshney, Rajeev K., Manish Roorkiwal, Shuai Sun, Prasad Bajaj, Annapurna Chitikineni, Mahendar Thudi, Narendra P. Singh, et al. "A chickpea genetic variation map based on the sequencing of 3,366 genomes." Nature 599, no. 7886 (November 10, 2021): 622–27. http://dx.doi.org/10.1038/s41586-021-04066-1.
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AbstractZero hunger and good health could be realized by 2030 through effective conservation, characterization and utilization of germplasm resources1. So far, few chickpea (Cicerarietinum) germplasm accessions have been characterized at the genome sequence level2. Here we present a detailed map of variation in 3,171 cultivated and 195 wild accessions to provide publicly available resources for chickpea genomics research and breeding. We constructed a chickpea pan-genome to describe genomic diversity across cultivated chickpea and its wild progenitor accessions. A divergence tree using genes present in around 80% of individuals in one species allowed us to estimate the divergence of Cicer over the last 21 million years. Our analysis found chromosomal segments and genes that show signatures of selection during domestication, migration and improvement. The chromosomal locations of deleterious mutations responsible for limited genetic diversity and decreased fitness were identified in elite germplasm. We identified superior haplotypes for improvement-related traits in landraces that can be introgressed into elite breeding lines through haplotype-based breeding, and found targets for purging deleterious alleles through genomics-assisted breeding and/or gene editing. Finally, we propose three crop breeding strategies based on genomic prediction to enhance crop productivity for 16 traits while avoiding the erosion of genetic diversity through optimal contribution selection (OCS)-based pre-breeding. The predicted performance for 100-seed weight, an important yield-related trait, increased by up to 23% and 12% with OCS- and haplotype-based genomic approaches, respectively.
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Knoth, Jenny, John Frampton, and Ray Moody. "Genetic Improvement of Virginia Pine Planting Stock for Christmas Tree Production in South Carolina." HortTechnology 12, no. 4 (January 2002): 675–78. http://dx.doi.org/10.21273/horttech.12.4.675.
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Twenty open-pollinated families from a virginia pine (Pinus virginiana) seed orchard in South Carolina were planted and managed as Christmas trees at three sites. Retail value and related traits were assessed once the tests reached marketable size (4 years in the field). All traits assessed (except survival) proved to 1) be under a moderate degree of genetic control (family mean heritability = 0.68 for retail value) and 2) have a large range among open-pollinated family means ($11.42/tree to $22.00/tree, retail value) suggesting that they will response well to the traditional tree improvement approach of selection, breeding and testing. The retail value of the best five families tested averaged an increase of $3.47/tree or 20.7% more than the average. At a 6 × 6 ft (1.8 m) spacing [1,210 trees/acre (2,990 trees/ha)], these families would produce an increase in revenue of almost $4,200/acre ($10,387/ha). Much of this increase in value is a result of reducing the cull rate from 14.5% to 8.1%. Survival, height, crown density and straightness of these five families also exceeded the average of the 20 families tested.
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Walker, Trevor D., W. Patrick Cumbie, and Fikret Isik. "Single-Step Genomic Analysis Increases the Accuracy of Within-Family Selection in a Clonally Replicated Population of Pinus taeda L." Forest Science 68, no. 1 (December 22, 2021): 37–52. http://dx.doi.org/10.1093/forsci/fxab054.
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Abstract The use of genomic markers in forest tree breeding is expected to improve the response to selection, especially within family. To evaluate the potential improvements from genotyping, we analyzed a large Pinus taeda L. clonal population (1,831 cloned individuals) tested in multiple environments. Of the total, 723 clones from five full-sib families were genotyped using 10,337 single-nucleotide polymorphism markers. Single-step models with genomic and pedigree-based relationships produced similar heritability estimates. Breeding value predictions were greatly improved with inclusion of genomic relationships, even when clonal replication was abundant. The improvement was limited to genotyped individuals and attributable to accounting for the Mendelian sampling effect. Reducing clonal replication by omitting data indicated that genotyping improved breeding values similar to clonal replication. Genomic selection predictive ability (masking phenotypes) was greater for stem straightness (0.68) than for growth traits (0.41 to 0.44). Predictive ability for a new full-sibling family was poorer than when full-sibling relationships were present between model training and validation sets. Species that are difficult to propagate clonally can use genotyping to improve within-family selection. Clonal testing combined with genotyping can produce breeding value accuracies adequate to graft selections directly into deployment orchards without progeny testing.
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Baird, Vance. "Progress in Prunus Mapping and Application of Molecular Markers to Germplasm Improvement." HortScience 30, no. 4 (July 1995): 748–49. http://dx.doi.org/10.21273/hortsci.30.4.748.
Full textAbstract:
Prunus, which includes peach/nectarine, almond, apricot, cherry, and plum, is a large and economically important genus in the family Rosaceae. The size and long generation time of these tree crops have hampered improvement through classical breeding and long-term selection programs. With the advent of DNA-based molecular diagnostics, an exciting era in germplasm improvement has dawned. Efforts are underway, notably in the United States (e.g., California, Michigan, North Carolina, and South Carolina) and the European Community (e.g., England, France, Italy, and Spain), to apply the tools of molecular mapping and marker-assisted selection to this important genus. The objective of these projects is to develop molecular linkage maps of sufficient marker density to tag phenotypic trait loci of agronomic importance. These include traits controlled by single genes (e.g., flower color, compatibility, flesh color, pest resistance), as well as more-complex, quantitative traits (e.g., cold hardiness, tree architecture, sugar content). An immediate outcome of these mapping efforts has been the development of DNA “fingerprints,” allowing for the discrimination of cultivars—both scion and rootstock. The maps will be used by breeders and molecular biologists to monitor gene introgression from wild species into elite lines, for marker-assisted selection of desired trait combinations, and for map-based cloning of specific genes. The molecular markers used in these mapping projects include RFLPs, RAPDs, and microsatellites. Each has their appropriate applications and advantages depending upon the resources at hand and the project's specific goals.
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Korneyeva, S. A., E. N. Sedov, and T. V. Yanchuk. "Evaluation of Priokskoe columnar apple variety from All-Russian Research Institute of Fruit Crop Breeding." Horticulture and viticulture, no. 4 (September 6, 2021): 32–36. http://dx.doi.org/10.31676/0235-2591-2021-4-32-36.
Full textAbstract:
The use of adaptive, scab-immune, stable-fruiting columnar apple tree varieties of domestic selection enhances profitability of commercial horticulture for a higher competitive power of national agricultural market. The diversity of columnar varieties remains little, yet offering a promising line of selection given a rising interest in this form of apple tree. The research aimed to comprehensively assess the economic and biological potential of the Priokskoe columnar variety to produce recommendations on its introduction in home and industrial gardening. A number of promising selected and elite genotypes, as well as five cultivars (Priokskoe, Poeziya, Vostorg, Orlovskaya Yeseniya, Girlyanda) have been identified from the extensive hybrid fund of columnar apple trees established at the All-Russian Research Institute of Fruit Crop Breeding for over 40 years. Priokskoe was the Institute’s first early-fruiting columnar variety starting at the third year post-inoculation on low-medium vigour rootstock. Average yield at planting density 14,000 plants/ha on dwarf stock 62-396 makes 49.1 t/ha and 78.3 t/ha — in the crown of skeleton-forming stock 3-17-38 at planting density 3,333 plants/ha. Priokskoe is a strong-vigour category among columnar varieties. A 7-year tree height on dwarf rootstock 62-396 was 217.3 cm, a crowned tree height on stem stock 3-4-98 — 281.7 cm. The variety’s winter hardiness is sufficient for its cultivation in the Middle Chernozem zone at no risk of irreversible winter loss. The Rvi6 gene-conditioned scab immunity enables improvement of the orchard phytosanitary situation via reduced chemical burden. The adaptability, economic and biological traits of the Priokskoe columnar variety ensure it a worthy rating among the current apple tree assortment recommended for intensive industrial horticulture.
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Cornelius, J. P., and E. K. Morgenstern. "An economic analysis of black spruce breeding in New Brunswick." Canadian Journal of Forest Research 16, no. 3 (June 1, 1986): 476–83. http://dx.doi.org/10.1139/x86-085.
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A representative black spruce (Piceamariana (Mill.) B.S.P.) breeding program was formulated using information collected from New Brunswick Tree Improvement Council cooperators. This "base program" was subjected to program profitability and program efficiency analyses. Costs and revenues were computed for a range of real discount rates. The results showed that variation in discount rates did not greatly influence the break-even level of gross discounted revenue, which was fairly stable at around $100 000 for the base orchard of 5.2 ha. Projected gross discounted revenue ranged from about $100 000 at 4.5% discount rate to $36 at 16%. With the internal rate of return at 4.4%, it was concluded that black spruce breeding is probably an economic means of securing extra wood supplies. The program efficiency component concentrated on resource allocation between plus-tree and family selection. The results suggested that current strategies are close to optimum; for a wide range of numbers of familis selected within a constant budget, gross returns remained within about 10% of the maximum possible for each assumption set. It was concluded that current breeding programs should be continued, with present recommended strategies retained.
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Norton, J. D., and Fenny Dane. "Resistance to Chestnut Blight in the American Chinquapin." HortScience 33, no. 4 (July 1998): 600g—601. http://dx.doi.org/10.21273/hortsci.33.4.600g.
Full textAbstract:
The American or Allegeny chinquapin (Castanea pumila) is native to the same area of the United States as the American chestnut (C. dentata) from Florida to Canada and westward to Arkansas. The high-quality nuts are an excellent source of food for wildlife and humans. Resistance to chestnut blight (Cryphnuectria parasitica) was discovered in seedlings in virgin forest at Elgin Air Force Base, Fla., with observations of plants for 35 years. A recurrent selection breeding program was established at Auburn Univ. to improve the blight resistance, precocity, dwarfism, pest resistance, cold hardiness, yield, and quality. A number of seedlings appear to be very promising selections for improvement of the American chinquapin. Since there is little information available regarding hereditability of certain traits in perennial tree species, results of breeding at Auburn Univ. should provide us with guidance for further improvement of the American chinquapin.
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Hamann, Andreas. "Utilization and management of red alder genetic resources in British Columbia." Forestry Chronicle 77, no. 4 (August 1, 2001): 705–12. http://dx.doi.org/10.5558/tfc77705-4.
Full textAbstract:
During the last two decades, the value of red alder wood products has substantially increased and several initiatives have been launched in the United States to use red alder for reforestation. Nonetheless, red alder is a largely neglected resource in British Columbia. This review paper examines the reasons behind the under-utilization of red alder in British Columbia and investigates whether changes in red alder management practices could improve the value of the resource. Red alder's potential for plantation forestry and genetic tree improvement are discussed, and possible breeding objectives were evaluated with consideration for the species biology, growth, product value and market demand. Seed transfer rules and the possibility of gains from selection are summarized in the light of new research results in genecology and quantitative genetics for red alder populations in British Columbia. Key words: red alder, Alnus rubra, tree improvement, quantitative genetics, genecology, resource management
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Xiao, Yao, Junhui Wang, Huiling Yun, Guijuan Yang, Jianwei Ma, Wenjun Ma, and Guanzheng Qu. "Genetic Evaluation and Combined Selection for the Simultaneous Improvement of Growth and Wood Properties in Catalpa bungei Clones." Forests 12, no. 7 (June 30, 2021): 868. http://dx.doi.org/10.3390/f12070868.
Full textAbstract:
Catalpa bungei is an important timber tree. Improvements in growth and wood quality are important goals of C. bungei breeding, and it is necessary to understand the genetic parameters of specific target traits and genetic correlation between growth traits and wood properties for tree breeding. In this study, the genetic parameters of height, diameter at breast height (DBH) and wood properties were estimated and genetic and phenotypic correlations between growth traits and wood properties were evaluated in C. bungei. Finally, different selection scenarios were used to evaluate and select optimal clones. The results showed that there were significant differences in growth and wood properties among clones. The wood hardness (0.66–0.79), basic density (0.89), air-dried density (0.89) and compression strength parallel to the grain of wood (CSP) (0.84) had high repeatability. The variance component proportions indicated that the variation in wood properties came mainly from different genotypes (clones) rather than from different individuals of the same clone. The DBH showed a significant negative genetic correlation with the hardness of radial section (HRS) (−643), basic density (−0.531) and air-dry density (−0.495). This unfavorable relationship makes it difficult to improve growth and wood quality simultaneously in C. bungei. We selected the optimal clones under different scenarios, and we obtained 7.75–9.06% genetic gains for growth in the scenario in which height and DBH were the target traits. Genetic gains of 7.43–14.94% were obtained for wood properties by selecting optimal clones in the scenario in which wood properties were the target traits. Approximately 5% and 4% genetic gains were obtained for growth and wood properties, respectively, for the combined selection. This study provides new insights into the genetic improvement of wood quality in C. bungei.
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Isik, Fikret, and Bailian Li. "Rapid assessment of wood density of live trees using the Resistograph for selection in tree improvement programs." Canadian Journal of Forest Research 33, no. 12 (December 1, 2003): 2426–35. http://dx.doi.org/10.1139/x03-176.
Full textAbstract:
Wood density is traditionally determined by a volumetric method that is accurate but expensive for large-scale sampling. A new device called the Resistograph was investigated for rapid assessment of relative wood density of live trees in progeny trials. Fourteen full-sib families of loblolly pine (Pinus taeda L.) produced by a six-parent half-diallel mating design were tested at four sites. For each family, wood density was measured with the traditional volumetric method and then compared with the Resistograph readings (amplitude). Amplitude had weak (0.29) to moderate (0.65) phenotypic correlations with wood density on an individual-tree basis over the four sites. The family mean correlation between the two measurements, however, was much stronger (0.92). The additive genetic correlation between the two measures was also high (0.95). Individual-tree breeding values of amplitude yielded more accurate rankings than phenotypic values. The rankings of the parental, general-combining abilities were identical for the two measures. Both wood density and amplitude were under strong genetic control at the family level (full-sib family heritability (h2fs) = 0.95 for wood density and h2fs = 0.85 for amplitude). The efficiency of using the Resistograph as a means of indirect selection for improvement of wood density was 87% at the family level. Results from this study suggest that the Resistograph could be used reliably and efficiently to assess relative wood density of live trees for selection in tree improvement programs. The method is rapid, nondestructive, and much cheaper than the traditional volumetric method.
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Khalilov, E. S., A. V. Smykov, E. F. Chelebiyev, and M. K. Uskov. "Commodity and consumer qualities and chemical composition of fruits of promising breeding forms of apple for the Crimea." Bulletin of the State Nikitsky Botanical Gardens, no. 139 (August 11, 2021): 91–99. http://dx.doi.org/10.36305/0513-1634-2021-139-91-99.
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The value of the fruits of the apple tree culture for the human diet is shown. The necessity of selection to improve the chemical composition of its fruits is justified. In the Russian Federation and the Republic of the Crimea as an integral part of it, all-round improvement of the varietal composition of apple trees should be accompanied by extensive use of the best selected or created new cultivars of local selection, including the Nikitsky Botanical Gardens. The objective of the research is to identify sources of economically valuable traits that are of interest for practical application and further selection. The article presents the results of a long-term study of the commodity and consumer qualities of 15 promising breeding forms of apple trees. The highest yield of commercial fruits was observed in four genotypes: 1-32-87, 2-6-13-82, 2-38-78, 3-6. The maximum weight of the fruit (226-224 g) differs in three breeding forms-3-6, 2-38-78, 3-6-47-79, according to the sugar content (12.7-13.1%), two are distinguished - 2-6-13-80 and 12-3-78. In terms of vitamin C content, four breeding forms, including 1-32-87 and 3-6, surpassed the control cultivar. During the organoleptic evaluation, the highest score was obtained by the control and selection forms 1-32-87 and 10-72-78. The selected genotypes are of considerable interest for practical use and selection.
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Matziris, D. "Genetic Variation and Realized Genetic Gain From Black Pine Tree Improvement." Silvae Genetica 54, no. 1-6 (December 1, 2005): 96–104. http://dx.doi.org/10.1515/sg-2005-0015.
Full textAbstract:
Summary In 1978 a 10 ha clonal seed orchard of black pine (Pinus nigra Arnold) was established in the area of Koumani in the western part of Peleponnesos, Greece. The orchard comprises 52 clones derived from intensively selected plus trees in the natural forest of black pine of Peloponnesos. In 1991 three open pollinated progeny tests were established in Peloponnesos, proximal to the villages of Raches, Vlachokerasia and Vamvakou. Seedlings from 52 families including a commercial check (CC) were planted in each one of the three locations. Assessments were made when the trees were 4, 7 and 9 years respectively, with the following results. The variation among families for growth characteristics were highly significant in all locations examined. In the combined analyses of variance over the three locations, significant differences among families were also detected, while the family x location interaction effect was not significant. This indicates that the seed produced from the seed orchard can be freely used over the environments of the three experimental plantings, which are representative of the broad area of Peloponnesos. Narrow sense heritability estimates on individual tree basis (h2) were variable depending on the characteristic, age of assessment and the location of the experimental plantings. The estimates of h2 in Vlachokerasia for height (HT) were 0.21, 0.40 and 0.43 at the ages of 4, 7 and 9 years respectively. In Raches the corresponding h2 values for HT were nearly the same in all ages (0.29, 0.28 and 0.31 at 4, 7 and 9 years respectively) and stable but little higher (0.31, 0.28 and 0.31) at the Vamvakou experimental planting. The heritability values for HT estimated over the three location, were relatively low (0.25, 0.23 and 0.19) at the ages 4, 7 and 9 years respectively. Realized genetic gains were calculated for growth characteristics at the age of 9 years, by comparing the performance of the improved (selected) materials to unimproved materials (CC). For the first stage of selection (selection made in natural stands) gain of 6.0% for HT, 8.0% for diameter breast height (DBH) and 24% for volume were estimated. When 20% of the clones, with the lower breeding values are removed from the seed orchard (genetic thinning), an additional gain of 2% for HT, 3% for DBH and 8% for volume over the unrogued seed orchard is resulted. Thus, the total genetic gain from the genetically tested, first generation seed orchard of black pine at Koumani is estimated as 8% for HT, 11% for DBH and 32% for volume. These results indicate that improvement of black pine by selection, establishment of seed orchard and progeny testing the clones, is a very promising profitable operation.
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Jiang, Qunyi, Shang-Heng Yen, Jiri Stiller, David Edwards, Paul T. Scott, and Peter M. Gresshoff. "Genetic, Biochemical, and Morphological Diversity of the Legume Biofuel Tree Pongamia pinnata." Plant Genetics, Genomics, and Biotechnology 1, no. 3 (June 15, 2017): 54–67. http://dx.doi.org/10.5147/pggb.v1i3.152.
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Pongamia pinnata is regarded as a sustainable biofuel feedstock of the future because of its abundant production of oil-rich seeds, tolerance to abiotic stress, and ability to undergo biological nitrogen fixation (minimizing nitrogen inputs). However, it needs extensive domestication through selection and genetic improvement. Owing to its outcrossing nature, Pongamia displays large phenotypic diversity, which is advantageous for selection of desirable phenotypes but problematic for plantation management. In this study, variation was evaluated for seed mass, oil content, and oil composition. To evaluate genetic diversity and to lay the basis for a molecular breeding approach we developed second generation sequencing (2GS)-derived ISSR markers (Pongamia Inter-Simple Sequence Repeats; PISSR). The special feature of PISSRs is that the number of nucleotide repeats and the 5’ and 3’ nucleotide extensions were not arbitrarily chosen, but were based on Pongamia genomic sequences obtained from a NGS (Illumina®) database. Amplification products were resolved by polyacrylamide gel electrophoresis and silver staining or automated capillary electrophoresis to yield distinct and reproducible profiles. Polymorphic bands were excised from polyacrylamide gels and sequenced to reveal similarity to DNA sequences from other legumes. We demonstrated: 1) an abundance of nucleotide core repeats in the Pongamia genome, 2) large genetic and phenotypic diversity among randomly sampled Pongamia trees, 3) restricted diversity in progeny derived from a single mature tree; 4) stability of PISSR markers in Pongamia clones; and 5) genomic DNA sequences within PISSR markers. PISSRs provide a valuable biotechnology tool for assessment of genetic diversity, gene tagging and molecular breeding in Pongamia pinnata.
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Cappa, Eduardo P., Jennifer G. Klutsch, Jaime Sebastian-Azcona, Blaise Ratcliffe, Xiaojing Wei, Letitia Da Ros, Yang Liu, et al. "Integrating genomic information and productivity and climate-adaptability traits into a regional white spruce breeding program." PLOS ONE 17, no. 3 (March 17, 2022): e0264549. http://dx.doi.org/10.1371/journal.pone.0264549.
Full textAbstract:
Tree improvement programs often focus on improving productivity-related traits; however, under present climate change scenarios, climate change-related (adaptive) traits should also be incorporated into such programs. Therefore, quantifying the genetic variation and correlations among productivity and adaptability traits, and the importance of genotype by environment interactions, including defense compounds involved in biotic and abiotic resistance, is essential for selecting parents for the production of resilient and sustainable forests. Here, we estimated quantitative genetic parameters for 15 growth, wood quality, drought resilience, and monoterpene traits for Picea glauca (Moench) Voss (white spruce). We sampled 1,540 trees from three open-pollinated progeny trials, genotyped with 467,224 SNP markers using genotyping-by-sequencing (GBS). We used the pedigree and SNP information to calculate, respectively, the average numerator and genomic relationship matrices, and univariate and multivariate individual-tree models to obtain estimates of (co)variance components. With few site-specific exceptions, all traits examined were under genetic control. Overall, higher heritability estimates were derived from the genomic- than their counterpart pedigree-based relationship matrix. Selection for height, generally, improved diameter and water use efficiency, but decreased wood density, microfibril angle, and drought resistance. Genome-based correlations between traits reaffirmed the pedigree-based correlations for most trait pairs. High and positive genetic correlations between sites were observed (average 0.68), except for those pairs involving the highest elevation, warmer, and moister site, specifically for growth and microfibril angle. These results illustrate the advantage of using genomic information jointly with productivity and adaptability traits, and defense compounds to enhance tree breeding selection for changing climate.
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Vergara, Rodrigo, Timothy L. White, Dudley A. Huber, Barry D. Shiver, and Donald L. Rockwood. "Estimated realized gains for first-generation slash pine (Pinus elliottii var. elliottii) tree improvement in the southeastern United States." Canadian Journal of Forest Research 34, no. 12 (December 1, 2004): 2587–600. http://dx.doi.org/10.1139/x04-136.
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Realized gains from selection of the first-generation breeding population of slash pine (Pinus elliottii Engelm. var. elliottii) were estimated using data from 38 field trials planted in large rectangular plots in the southeastern United States. The trials consisted of material selected for volume growth and planted by the Cooperative Forest Genetics Research Program at the University of Florida (19 trials) and by the Plantation Management Research Cooperative at the University of Georgia (19 trials). All trials contained slash pine seedlots collected from unrogued or lightly rogued first-generation seed orchards. Analyses of variance detected, on average, moderate gains in rust resistance (I50 = 43.1%) and site index (4.3%) and important gains in individual tree volume (7.7%) and stand yield (10.2%). Silvicultural treatments and age by realized gains interactions were never significant, but significant interactions between seedlots and trials showed that realized gains are not consistent at all sites. Overall results were highly consistent with predicted breeding values for rust resistance, but lower than expected for volume. On average, realized gain in stand yield for first-generation material was approximately 10%, or an extra inside-bark volume of 25 m3·ha1 (357 feet3·acre1) at 25 years.
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Almeida, Patrícia de, Bruno Ettore Pavan, Maria Gabriela Fontanetti Rodrigues, Guilherme de Freitas Gaspar, Leonardo de Paula Giro, and Renan Furquim da Silva. "Genetic parameters and gains with the selection of fig tree genotypes." Acta Scientiarum. Agronomy 44 (June 29, 2022): e55796. http://dx.doi.org/10.4025/actasciagron.v44i1.55796.
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Fig tree (Ficus carica L., Moraceae), which originated in the Mediterranean Basin, is one of the many fruit trees grown in Brazil, with ‘Roxo-de-Valinhos’ being the exclusively used cultivar. In this context, research aimed at the improvement of this species to develop highly resistant and adaptable cultivars is paramount. Thus, the present study aimed to maintain fig accessions in an in vivo active germplasm bank (AGB) at the Faculty of Engineering of Ilha Solteira (FEIS), São Paulo State University (UNESP), as well as to characterize the agronomic traits of these accessions based on quantitative descriptors of genetic parameters and observe gains with the selection of specific genotypes to illustrate the AGB in terms of genetic variability. A total of 36 F. carica genotypes were evaluated in the field at the Teaching, Research and Extension Farm (FEPE) of the FEIS, UNESP. Qualitative traits, fruit parameters (e.g., insertion of the first fruit, fruit stalk length, fruit length, fruit diameter, and average fruit mass), and accumulated plant dry mass were measured. In addition, genetic parameters, variance components, and descriptive statistics, including genetic and environmental variances, heritability and average heritability of clones, coefficients of genotypic and environmental variation and their ratio ( ), general average, and selection gain, were evaluated. The selected fig tree accessions showed genetic variability in the assessed traits, exhibiting good heritability and achieving selection gains. For instance, the first 10 classified clones exhibited a heritability of 80.2% and achieved a selection gain of 98% for accumulated plant dry mass. Therefore, the maintenance of in vivo AGBs allows agronomic studies, offering promising results for continuing the breeding programs and preserving the genetic variability of species.
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Klápště, Jaroslav, Ahmed Ismael, Mark Paget, Natalie J. Graham, Grahame T. Stovold, Heidi S. Dungey, and Gancho T. Slavov. "Genomics-Enabled Management of Genetic Resources in Radiata Pine." Forests 13, no. 2 (February 10, 2022): 282. http://dx.doi.org/10.3390/f13020282.
Full textAbstract:
Traditional tree improvement is cumbersome and costly. Our main objective was to assess the extent to which genomic data can currently accelerate and improve decision making in this field. We used diameter at breast height (DBH) and wood density (WD) data for 4430 tree genotypes and single-nucleotide polymorphism (SNP) data for 2446 tree genotypes. Pedigree reconstruction was performed using a combination of maximum likelihood parentage assignment and matching based on identity-by-state (IBS) similarity. In addition, we used best linear unbiased prediction (BLUP) methods to predict phenotypes using SNP markers (GBLUP), recorded pedigree information (ABLUP), and single-step “blended” BLUP (HBLUP) combining SNP and pedigree information. We substantially improved the accuracy of pedigree records, resolving the inconsistent parental information of 506 tree genotypes. This led to substantially increased predictive ability (i.e., by up to 87%) in HBLUP analyses compared to a baseline from ABLUP. Genomic prediction was possible across populations and within previously untested families with moderately large training populations (N = 800–1200 tree genotypes) and using as few as 2000–5000 SNP markers. HBLUP was generally more effective than traditional ABLUP approaches, particularly after dealing appropriately with pedigree uncertainties. Our study provides evidence that genome-wide marker data can significantly enhance tree improvement. The operational implementation of genomic selection has started in radiata pine breeding in New Zealand, but further reductions in DNA extraction and genotyping costs may be required to realise the full potential of this approach.
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Johnson, G. R., N. C. Wheeler, and S. H. Strauss. "Financial feasibility of marker-aided selection in Douglas-fir." Canadian Journal of Forest Research 30, no. 12 (December 1, 2000): 1942–52. http://dx.doi.org/10.1139/x00-122.
Full textAbstract:
The land area required for a marker-aided selection (MAS) program to break-even (i.e., have equal costs and benefits) was estimated using computer simulation for coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in the Pacific Northwestern United States. We compared the selection efficiency obtained when using an index that included the phenotype and marker score with that obtained using only the phenotype. It was assumed that MAS was restricted to within-family selection, that the rotation age was 50 years, and that growth rate (h2 = 0.25), tree form (h2 = 0.25), and (or) wood density (h2 = 0.45) were the objects of improvement. Several population quantitative trait loci (QTL) models, selection population sizes, and interest rates were considered. When large selection population sizes were employed (500 trees per family) MAS gave considerable increases in efficiency of within-family selection; however, results showed that the combination of small selection population sizes (100 trees per family) and many QTL of moderate effect could lead to losses in gain from MAS compared with phenotypic selection. For many reasonable selection scenarios and the simplified assumptions in our model, the land base required for breeding programs to break-even is smaller or near to the limit of those in place under operational breeding programs in the region. Considerably more research is needed to reasonably predict whether MAS would be cost-effective in practice. However, before some of the basic research needed to implement MAS can be done, organizations need to establish large blocks of full-sib families to allow for QTL identification.
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Suontama, Mari, Yongjun Li, Charlie B. Low, and Heidi S. Dungey. "Genetic improvement of resistance to cyclaneusma needle cast in Pinus radiata." Canadian Journal of Forest Research 49, no. 2 (February 2019): 128–33. http://dx.doi.org/10.1139/cjfr-2018-0075.
Full textAbstract:
Progeny testing of resistance to needle loss caused by Cyclaneusma minus (cyclaneusma needle cast) has been included in the needle disease resistance strategy of Pinus radiata D. Don in New Zealand since the late 1970s. Data on progeny trials, two in the North Island of New Zealand and one in Tasmania, Australia, were available to estimate heritability between trait genetic correlations and genotype × environment interaction. Resistance to cyclaneusma needle cast had moderate estimates of heritability (0.25 to 0.46) at all sites. Genetic correlations between the assessed traits indicated that selection for faster early growth, i.e., tree height at age 4 years and diameter at breast height at age 6 years, favours trees that are prone to Cyclaneusma infection, while a favourable genetic association between resistance to cyclaneusma needle cast and productivity was evident at a later assessment at age 9 years. No significant genotype × environment interaction was found for resistance to cyclaneusma needle cast; however, stability of genotypes across a wider range of environments and with a high genetic connectedness requires more research. Considerable genetic improvement can be achieved for resistance to cyclaneusma needle cast and indirect selection for the trait should be pursued by selecting for productivity and culling susceptible genotypes from breeding.
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Bouffier, Laurent, Philippe Rozenberg, Annie Raffin, and Antoine Kremer. "Wood density variability in successive breeding populations of maritime pine." Canadian Journal of Forest Research 38, no. 8 (August 2008): 2148–58. http://dx.doi.org/10.1139/x08-051.
Full textAbstract:
Growth and form are the two main traits used for genetic improvement of maritime pine ( Pinus pinaster Ait.) in the southwest of France. In this paper, wood density is studied to answer two main questions: Is there a general trend for density variability throughout tree development and has selection indirectly reduced wood density variability over breeding populations, owing to genetic unfavourable correlation with growth? Wood density and its components were studied in three polycross tests, each representative of one of the successive breeding populations. Wood density was measured with an X-ray densitometer in approximately 50 families per test with >1900 trees. A preliminary study showed that bark-to-pith ring indexing allows for a better estimation of genetic effects than does pith-to-bark indexing. Genetic variability of wood density appears to be highly dependent on the year considered and no general pattern can be detected over time. Whereas the variability of selected traits is known to have decreased over breeding populations, no significant change was found for variability of wood density.
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Smith, K. F., and P. F. Fennessy. "The use of conjoint analysis to determine the relative importance of specific traits as selection criteria for the improvement of perennial pasture species in Australia." Crop and Pasture Science 62, no. 4 (2011): 355. http://dx.doi.org/10.1071/cp10320.
Full textAbstract:
Despite the large number of active programs breeding improved forage plants, relatively little is known about the weightings that breeders consciously or subconsciously give to specific traits when selecting individual plants or that agronomists and producers use when assessing the relative merits of contrasting cultivars. This is in contrast to most modern animal breeding programs where the relative merits of novel genetics may be assessed against an index-based breeding objective. These technologies have not been widely used in crop or forage plant breeding but their use in forest tree breeding is relatively common. We have assessed the usefulness of discrete choice experiment techniques in the development of weightings for specific traits in forage plant improvement based on the views of an expert panel (plant breeders and non-breeders – agronomists, nutritionists, senior managers in breeding companies and consultants) asked to consider the requirements in four species (white clover, lucerne, perennial ryegrass and tall fescue). The results indicate that criteria related to abiotic stress tolerance, adaptation or the costs of pasture (root growth, drought tolerance, persistence, resistance to invertebrate pests, tolerance of hostile soil conditions) were deemed to be particularly important for white clover, while the highest-rated criteria for lucerne were not dissimilar, being tolerance of hostile soil conditions, persistence and tolerance of transient water-logging. For perennial ryegrass, three of the five highest-weighted criteria (drought tolerance, root growth, rate of recovery of pasture after water) are related to yield in environments where too much or too little water is a problem, highlighting the importance that the experts placed on the ability of the plant to withstand this important abiotic stress. For tall fescue, the highest-rated criteria were seedling vigour, drought tolerance, and persistence. Overall the preference weightings tended to reflect the perceived limitations of the various species, such as the priority of seedling vigour in tall fescue. This focus on the importance of abiotic stress is especially interesting as previous attempts to identify priorities have focused on the forage quality traits rather than analysing their importance relative to traits related to herbage yield or stress tolerance. This study highlights the importance of further work to help determine the focus of breeding objectives and selection criteria for different pasture species across production systems.
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Szyp-Borowska, Iwona, Joanna Ukalska, Marzena Niemczyk, Tomasz Wojda, and Barb R. Thomas. "Effects of Water Deficit Stress on Growth Parameters of Robinia pseudoacacia L. Selected Clones under In Vitro Conditions." Forests 13, no. 12 (November 23, 2022): 1979. http://dx.doi.org/10.3390/f13121979.
Full textAbstract:
Rapid screening methods for drought-resistant genotypes are urgently needed in tree improvement programs in the face of current climate change. We used a plant tissue culture technique to assess the phenotypic response of three highly productive genotypes of Robinia pseudoacacia to water deficit induced by mannitol and sucrose in a range of water potentials from 0 MPa to −1.5 MPa in an eight-week experiment. Our study showed genotype-specific responses to induced drought stress, indicating the potential for tree improvement in productivity and stress tolerance. Considering that all plantlets were constantly supplied with carbon, from the medium during the drought-induced experiment, our results suggest that hydraulic failure rather than carbon starvation may be the main cause of drought-induced mortality. Furthermore, our results showed different metabolic pathways of sucrose depending on the concentration of sucrose in the medium and different responses to osmoticum (mannitol vs. sucrose) and its concentration among the clones tested. We believe, that for large-scale breeding programs wanting to select for drought-tolerant genotypes, the use of culture media containing 90 gL−1 mannitol or 90 gL−1 sucrose at an early selection stage should provide satisfactory screening results. However, lab-based screening should be supported by further field trials, preferably at multiple sites, to assess the long-term impact and phenotypic stability of the early selection strategies.
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Smith, Kevin F., and Peter F. Fennessy. "Utilizing Conjoint Analysis to Develop Breeding Objectives for the Improvement of Pasture Species for Contrasting Environments When the Relative Values of Individual Traits Are Difficult to Assess." Sustainable Agriculture Research 3, no. 2 (March 5, 2014): 44. http://dx.doi.org/10.5539/sar.v3n2p44.
Full textAbstract:
<p>Despite the large number of active programs breeding improved forage plants, relatively little is known about the weightings that breeders consciously or sub-consciously give to specific traits when selecting individual plants, or that agronomists and producers use when assessing the relative merits of contrasting cultivars. This is in contrast to most modern animal breeding programs where the relative merits of novel genetics may be assessed against an index-based breeding objective. There are numbers of reasons why these technologies have not been used widely in plant breeding although applications in forest tree breeding are relatively common. A first step in defining breeding objectives for forage species can be to define the relative importance of specific traits and to interpret how these contribute to the relative potential advantage to a new plant or cultivar. One method of defining these weightings is through surveys of users followed by analyses of their combined experience. Therefore in this study, we have assessed the usefulness of discrete choice techniques in the development of weightings for specific traits in forage plant improvement based on views of both expert users (agronomists and farm consultants) and farmers who were asked to define their relative priorities when considering the renovation of a pasture. The surveys were conducted in three distinct regions of, or environments within, Australia of special relevance to meat production from beef and sheep (high rainfall, temperate (inland), and Mediterranean). In summary this study defines the focus of breeding objectives and selection criteria for different pasture species across production systems.</p>
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Rocha-Sepúlveda, Manuel F., Dean Williams, Mario Vega, Peter A. Harrison, René E. Vaillancourt, and Brad M. Potts. "Genetic variation of microfibril angle and its relationship with solid wood and pulpwood traits in two progeny trials of Eucalyptus nitens in Tasmania." Holzforschung 75, no. 8 (January 8, 2021): 689–701. http://dx.doi.org/10.1515/hf-2020-0196.
Full textAbstract:
Abstract Microfibril angle (MFA) is a key biological trait contributing to wood stiffness, which is a common breeding objective for solid wood products in many tree species. To explore its genetic architecture, area-weighted MFA was measured in two Eucalyptus nitens progeny trials in Tasmania, Australia, with common open-pollinated families. Radial strips were extracted from 823 trees in 131 families and MFA assessed using SilviScan-2®. Heritability, genotype-by-environment interaction and inter-trait genetic correlations were evaluated to examine the genetic variability and stability of MFA and its relationships with other solid wood and pulpwood selection traits. Significant family variation was found for MFA in both trials. There was no significant genotype-by-environment interaction and the across-site narrow-sense heritability was 0.27. MFA was genetically independent of basic density, growth, and tree form. However, MFA was strongly and favourable genetically correlated to acoustic wave velocity in standing trees, modulus of elasticity and kraft pulp yield (KPY). The present study has shown that genetic improvement of E. nitens for pulpwood selection traits is unlikely to have adversely affected MFA, and thus timber stiffness. Rather these results suggest the possibility that selection for increased KPY may have indirectly improved MFA favourably for solid wood products.
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Pinheiro, Diogo Santos, Maria Clideana Cabral Maia, Francisco Edinaldo Pinto Mousinho, Luís Cláudio De Oliveira, Renato Domiciano Silva Rosado, and Gilberto Ken-Iti Yokomizo. "Repeatability estimation for mangaba selection using mixed models." REVISTA AGRO@MBIENTE ON-LINE 13 (November 26, 2019): 243. http://dx.doi.org/10.18227/1982-8470ragro.v13i0.5758.
Full textAbstract:
The Mangaba (Hancornia speciosa Gomes) is a fruit tree rich in such essential vitamins as iron, calcium and protein, and plays an important social, cultural and economic role for farmers in the Cerrado and Caatinga biomes of Brazil. The aim of this study was to estimate genetic parameters and genetic gains in the agrotechnological attributes of a breeding population of the mangaba from Embrapa Meio Norte. The variables under analysis were: fruit weight (FW, g), fruit length (FL, mm), fruit diameter (FD, mm), skin weight (SW, g), number of seeds per fruit (NSF,nondimensional), seed weight (SW, g), total soluble solids (TSS,ºBrix), total titratable acidity (TTA,%), TSS/TTA ratio, pulp weight (PW, g) and percentage pulp (%Pulp, percentage). The data were analysed using the REML/BLUP procedure of the Selegen software. High and intermediate estimates of the components of repeatability were found for the variables of the population under study. It can therefore be inferred that these variables can be used in genetic studies, with a view to an increase in the efficiency of the selection process and to a progressive advance in the breeding population of this important native species. As such, taking repeatability as the limit to be assumed for heritability, the values obtained can be considered satisfactory in terms of genetic progress, showing good reliability for the phenotypic value as an indicator of genotypic value and significant repeatability of the expression of the evaluated trait. Genetic gains were seen for genotypes 6 and 12, considering the silmultaneous selection of eight highlighted genotypes based on the most important attributes of the improvement program, and which can contribute to the productive sector.
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Grosser, Jude W. "693 Practical Applications of Citrus Protoplast Technology." HortScience 35, no. 3 (June 2000): 518D—518. http://dx.doi.org/10.21273/hortsci.35.3.518d.
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Citrus protoplast technology has advanced to where several practical applications in variety improvement and plant pathology are routine. We will report on progress in the following areas: somaclonal variation—`Valencia` and `Hamlin' sweet orange protoclones have been selected for improved juice color, higher soluble solids, seedlessness, and altered maturity dates; somatic hybridization for scion improvement—allotetraploid breeding parents have been created from numerous combinations of elite parental material, and are now being used as pollen parents in interploid crosses to produce seedless triploid varieties; somatic hybridization for rootstock improvement—numerous somatic hybrids combining complementary rootstock germplasm are under commercial evaluation and several look promising for wide adaptation, improved disease resistance, and tree size control; transformation—an alternative protoplast-based transformation that utilizes EGFP for selection has been developed; virus resistance assays—a protoplast-based assay is being used to screen varieties and candidate sequences for resistance to citrus tristeza virus at the cell level, saving time and greenhouse space.
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Weng, Y. H., K. J. Tosh, and M. S. Fullarton. "Effects of height-growth selection on wood density in black spruce in New Brunswick, Canada." Forestry Chronicle 87, no. 1 (February 1, 2011): 116–21. http://dx.doi.org/10.5558/tfc87116-1.
Full textAbstract:
Height growth was the main selection criterion for the early-stage black spruce (Picea mariana [Mill.] BSP) breeding programmein New Brunswick, which has produced significant increases in volume growth. In this study we investigate howthe height-growth selection influences growth traits and wood density. Two genetic tests, a realized gain test of large plotsand a progeny test of small plots, were used for this purpose. Wood density was measured using the Resistograph methodon the standing trees. Growth and wood density of the improved seedlots were compared with those of an unimprovedstand checklot. In the progeny test, height-growth selection not only made the improved seedlots taller but also produceda proportional increase in DBH growth relative to the checklot. In the realized gain test, height-growth selection didincrease height, but did not produce a corresponding increase in DBH growth. Effects of height-growth selection on wooddensity varied with tests: the improved seedlot produced a greater although statistically non-significant decline in wooddensity in the progeny test; this reduction was at a much lesser extent or even non-existent in the realized gain test. Overall,results suggest that the improved growth from early stage improvement activities might not substantially and negativelyaffect wood density in plantation forestry and the predicted reduction in wood density in genetic tests of small plotsmight be inflated. Key words: Resistograph, realized gain test, progeny test, tree improvement
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Baldi, Paolo, and Nicola La Porta. "Toward the Genetic Improvement of Drought Tolerance in Conifers: An Integrated Approach." Forests 13, no. 12 (November 29, 2022): 2016. http://dx.doi.org/10.3390/f13122016.
Full textAbstract:
The constant rise in the global temperature and unpredictable shifts in precipitation patterns are two of the main effects of climate change. Therefore, there is an increasing amount of interest in the identification of tree species, provenances and genotypes capable of withstanding more arid conditions and tolerating drought stress. In the present review, we focus our attention on generally more susceptible conifers and describe the different strategies that plants adopt to respond to drought stress. We describe the main approaches taken in studies of conifer adaptations to low water availability, the advantages and limitations of each, and the main results obtained with each of these approaches in the recent years. Then we discuss how the increasing amount of morphological, physiological and genetic data may find practical applications in forest management, and in particular in next-generation breeding programs. Finally, we provide some recommendations for future research. In particular, we suggest extending future studies to a broader selection of species and genera, increasing the number of studies on adult plants, in particular those on gene expression, and distinguishing between the different types of drought stress that a tree can withstand during its life cycle. The integration of data coming from different disciplines and approaches will be a key factor to increasing our knowledge about a trait as complex as drought resistance.
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Hanchor, Uraiwan, Somporn Maelim, Wathinee Suanpaga, Ji-Min Park, and Kyu-Suk Kang. "Growth Performance and Heritability Estimation of Acacia crassicarpa in a Progeny Trial in eastern Thailand." Silvae Genetica 65, no. 2 (December 1, 2016): 58–64. http://dx.doi.org/10.1515/sg-2016-0017.
Full textAbstract:
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 (h2) 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 (h2 = 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.