scholarly journals ESTIMATIVAS DE PARÂMETROS GENÉTICOS PARA CARACTERES QUANTITATIVOS EM PROGÊNIES DE POLINIZAÇÃO ABERTA DE Eucalyptus urophylla

FLORESTA ◽  
2011 ◽  
Vol 41 (4) ◽  
Author(s):  
Cidinei Santos de Souza ◽  
Miguel Luiz Menezes Freitas ◽  
Mário Luiz Teixeira de Moraes ◽  
Alexandre Magno Sebbenn

Eucalyptus urophylla S. T. Blake destaca-se pelo potencial de utilização de sua madeira, plasticidade de adaptação a diferentes condições ambientais e por ser tolerante ao cancro. Entretanto, o melhoramento genético da espécie no Brasil depende da existência de variabilidade genética nas populações introduzidas. O objetivo deste estudo foi investigar a variação genética e estimar ganhos na seleção para caracteres quantitativos de uma população base de E. urophylla instalada em 1992 em Selvíria (MS). O teste de progênies foi instalado no delineamento experimental em Látice 8 x 8, quíntuplo, parcialmente balanceado, com 64 progênies provenientes da Estação Experimental de Anhembi (IPEF/ESALQ/USP). As parcelas continham oito árvores, no espaçamento de 3 x 3 m. Foram detectadas variações genéticas entre progênies para diâmetro à altura do peito (DAP), tipo de casca, forma e sobrevivência. As estimativas de herdabilidade, em nível de média, foram altas para DAP, tipo de casca e forma, variando de 0,50 a 0,85. A seleção pelo índice multiefeitos demonstrou que o número variável de plantas por progênie foi mais indicada para a maximização de ganhos genéticos (7,24%) e tamanho efetivo populacional (69,3). Esses resultados subsidiarão a transformação do teste em pomar de sementes por mudas e fornecimento de material para formação de pomar de sementes clonal.Palavras-chave: Ganhos na seleção; herdabilidade; melhoramento genético; variância genética. AbstractEstimates of genetic parameters for quantitative traits in open-pollinated families of Eucalyptus urophylla. Eucalyptus urophylla S. T. Blake is outstanding for valuable wood production potential, adaptation plasticity for different environmental conditions, and for tolerance to canker. However, genetic improvement of this specie in Brazil depends on the existence of genetic variability in the introduced populations. The objective of this study was to investigate the genetic variation and gains in quantitative traits in a population established in 1992 in Selvíria - MS. The progeny trial was established in a partially balanced, 8 x 8 lattice design, with 64 families, collected at Anhembi Experimental Station (IPEF/ESALQ/USP). Each plot was made up of eight trees planted in a 3 x 3 m spacing. Significant among families genetic variations were observed in diameter at breast height (DBH), bark type, stem form, and survival. Estimates of average family heritability were high for all traits, ranging from 0.50 to 0.85. The simulated selection by using multi-effect index showed that under a varying number of plants per family. This method is the most indicated to maximize genetic gains (7.24%) and the effective population size (69.3). These results are a useful support for the transformation of this test into a seedling seed orchard and to become a source of vegetative material to build a clonal seed orchard.Keywords: Heritability; gains in selection; genetic variance; progeny test; tree breeding.

2005 ◽  
Vol 54 (1-6) ◽  
pp. 218-227 ◽  
Author(s):  
J. K. Hansen ◽  
H. Wellendorf ◽  
E. D. Kjær

Abstract An evaluation of a seedling seed orchard in Denmark of Coastal Douglas-fir showed variation between open pollinated families in their susceptibility to windthrow, height and diameter growth, stem straightness, number of forks at age 10 and bud burst at age 9. Individual narrow-sense heritability was 0.63 for bud burst, 0.40 for height and diameter, respectively, 0.48 for stem straightness, 0.20 for number of forks and 0.17 for windthrow susceptibility. Fast growing families were characterised by late bud burst, and poorer stem straightness. The approach of using seedling seed orchards in Denmark is discussed in relation to genetic gains, genetic diversity and risk of inbreeding. Predicted gains concerning a reduction of windthrow susceptibility were poor due to low genetic variability. In multi-trait selection scenarios aiming to improve growth, stem straightness and reducing windthrow susceptibility, the approach of using seedling seed orchards demonstrated that it might be possible to obtain gains in height above 5% combined with significant improvements of stem straightness while retaining an effective population size above 50.


2019 ◽  
Vol 437 ◽  
pp. 272-281 ◽  
Author(s):  
Silvelise Pupin ◽  
Alexandre M. Sebbenn ◽  
Jose Cambuim ◽  
Alexandre M. da Silva ◽  
Darlin U.G. Zaruma ◽  
...  

2006 ◽  
Vol 36 (4) ◽  
pp. 1054-1058 ◽  
Author(s):  
O K Hansen ◽  
E D Kjær

A paternity analysis using five microsatellite markers was conducted in a Danish clonal seed orchard with 13 Abies nordmanniana (Stev.) Spach clones. The purpose was to investigate potential seed-orchard dysfunctions, with special emphasis on nonequal pollen contributions and selfing. Male paternity was found for 232 seedlings germinated from seeds collected on three ramets, each of eight clones, and the relative contribution of each clone to the gene pool of male gametes was calculated. Furthermore, 49 ramets were genotyped to check for erroneous grafting. The effect of an unbalanced male contribution was quantified by means of two measures: (1) the status number (NS), which reflects buildup of coancestry in the seed-orchard crop as a result of a low number of clones and an unequal male contribution, and (2) the asymptotic variance effective population number (Ne(v)). The contributions by pollen donors from the 13 clones were highly skewed. Three clones were fathers to more than 75% of the progenies, while making up only 24% of the ramets in the seed orchard. Four clones sired no progenies at all. The unequal contribution on the male side corresponded to NS = 4.2 and Ne(v) = 5.8. Some selfing was observed, which may give rise to concern if clonal seed orchards with few clones are established. The estimated maximum pollen contamination from outside the seed orchard was 4.3%. No grafting–labelling errors were identified.


2021 ◽  
Vol 17 (4) ◽  
Author(s):  
Joukje Buiteveld ◽  
Herma JJ Koehorst-van Putten ◽  
Linda Kodde ◽  
Ivo Laros ◽  
Giorgio Tumino ◽  
...  

AbstractThe Netherlands’ field genebank collection of European wild apple (Malus sylvestris), consisting of 115 accessions, was studied in order to determine whether duplicates and mistakes had been introduced, and to develop a strategy to optimize the planting design of the collection as a seed orchard. We used the apple 20K Infinium single nucleotide polymorphism (SNP) array, developed in M. domestica, for the first time for genotyping in M. sylvestris. We could readily detect the clonal copies and unexpected duplicates. Thirty-two M. sylvestris accessions (29%) showed a close genetic relationship (parent-child, full-sib, or half-sib) to another accession, which reflects the small effective population size of the in situ populations. Traces of introgression from M. domestica were only found in 7 individuals. This indicates that pollination preferentially took place among the M. sylvestris trees. We conclude that the collection can be considered as mainly pure M. sylvestris accessions. The results imply that it should be managed as one unit when used for seed production. A bias in allele frequencies in the seeds may be prevented by not harvesting all accessions with a close genetic relationship to the others in the seed orchard. We discuss the value of using the SNP array to elaborate the M. sylvestris genetic resources more in depth, including for phasing the markers in a subset of the accessions, as a first step towards genetic resources management at the level of haplotypes.


2019 ◽  
Vol 9 (2) ◽  
pp. 99-108
Author(s):  
Supriyanto . ◽  
Taufik Iskandar

Pine (Pinus merkusii) is tree species that provides timber and gum rosin. To meet the needs of wood and non wood (gum rosin) products, planting by using superior or high quality seeds are needed. Seed procurements for planting are obtained from seedling seed orchard (SSO). However, Cijambu’s SSO was attacked by pine woolly aphid (Pineus boerneri). Therefore, assessment of Cijambu’s SSO needs to be done to evaluate the severity pest attacks that could affect to the quality and the quantity of seed production. Forest Health Monitoring (FHM) method is one of the methods to assess the health level of a stand. The number of trees found in all cluster plots in Cijambu’s SSO were 270 trees. Based on the value of the VCR (Visual Crown Rating), the trees located in all cluster plot have health level between low to high. Based on the value of the VCR showed 38.52% (104 trees) having VCR’s value was high, 49.26% (133 trees) having VCR’s value was middle; 12.22% (33 trees) having VCR’s value was low; and no tree having very low VCR’s value. The average of VCR’s value in all cluster plots were 3.25 and classified as middle health. Based on the value of TDLI (Tree Damage Level Index) from 270 trees in all cluster plot showed that 189 trees (70.00%) in healthy condition; 69 trees (25.56%) in slight damage condition; 11 trees (4.07%) in middle damage condition; and 1 tree (0.37%) in heavy damage condition. The value of damage in all cluster plots (ALI) was 261.22 and classified as in health condition. The trees located in all cluster plots were mostly suitable to be seed sources as 242 trees (89.63%), while 28 trees (10.37%) were not suitable for seed sources.Keywords: Forest Health Monitoring, Pinus merkusii, seedling seed orchard, Tree Damage Level Index, Visual Crown Rating


1976 ◽  
Vol 52 (6) ◽  
pp. 283-289 ◽  
Author(s):  
C. W. Yeatman

A program of provenance testing, seed production and genetic improvement of jack pine was developed in the Baskatong region of western Quebec through sustained collaboration among government forest services and forest industry. Research plantations demonstrated, within a period of 10 years from establishment, the superiority in growth, cold hardiness and disease resistance of regionally adapted local seed sources. Critical differences were evident between provenances from the Boreal Forest Region and those from the adjacent Sections of the Great Lakes — St. Lawrence Forest Region.A 300-acre (120 ha) seed production area was created within a genetically superior jack pine population of natural origin in the Côte Jaune area west of Lake Baskatong. Within this population, 325 plus trees were selected, marked and recorded over two years by student crews employed in the summer. Seed harvested from the felled plus trees will be used to create a seedling seed orchard and to establish progeny tests. The plus trees are to be grafted for controlled breeding among selected progeny-tested clones at a later date. This cooperative program of tree improvement will ensure the future supply of high quality seed that will maintain and enhance the value of the forest resource.


Bragantia ◽  
2009 ◽  
Vol 68 (3) ◽  
pp. 629-637 ◽  
Author(s):  
Ananda Virginia de Aguiar ◽  
Roland Vencovsky ◽  
Lázaro José Chaves ◽  
Mara Fernandes Moura ◽  
Lizz Kezzy de Morais

The objective of this study was to estimate genetic parameters of quantitative traits in a living germplasm collection of Eugenia dysenterica. The genetic material consisted of 110 progenies derived from 10 natural Eugenia dysenterica subpopulations sampled in the southeastern region of the state of Goiás. The experiment was established in a complete randomized block design, with 110 treatments, four replications and one tree per plot. The study variables were total height, stem diameter and respective growth rates. After the analysis of variance some genetic parameters were estimated. The levels of genetic variation in the collection were high and the highest proportion was found within subpopulations. Highest coefficients of heritability and genetic variation were observed in subpopulations from the counties Catalão, Três Ranchos, Cristalina and Senador Canedo. Considering the promising expected progress for growth traits, this collection can be converted into an unrogued seedling seed orchard, aiming the production of improved seed.


2007 ◽  
Vol 37 (4) ◽  
pp. 773-785 ◽  
Author(s):  
Vincent Tripiana ◽  
Michaël Bourgeois ◽  
Daniel Verhaegen ◽  
Philippe Vigneron ◽  
Jean-Marc Bouvet

Genetic diversity and structure of 17 populations representative of the natural range of Eucalyptus urophylla S.T. Blake in Indonesia were analysed with 10 microsatellite markers. Two provenance and progeny trials, using the same populations, were established in the Republic of the Congo and analysed for growth and survival at 37 months. Observed microsatellite heterozygosity (Ho) was moderate to high within populations (Ho = 0.51–0.72). The index of fixation (FIS) was significantly different from zero for all populations (FIS = 0.13–0.31) and possibly resulted from a Wahlund effect. The differentiation parameter was low (FST = 0.04) and not significantly different from zero, which can be explained by effective gene flow via pollen. The genetic variances within and among provenances for survival and growth traits were significantly different from zero, representing 13%–23% and 14%–50% of the total variation, respectively. The differentiation between populations based on quantitative traits was marked (QST = 0.07–0.33). A negative relationship between altitude of the seed source and its performance in the Congo was observed (R2 = 0.59–0.67) and could be explained by the effect of natural selection along the altitudinal gradient. This marked differentiation for quantitative traits despite high apparent gene flow results in a clinal variation, which suggests the use of altitude of seed source as an important principle for in situ or ex situ management of E. urophylla genetic resources.


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