N. D. Kien, G. Jansson, C. Harwood and C. Almqvist
A total of 172 clones of Eucalyptus camaldulensis were tested in three clonal tests in northern, north-central and southern Vietnam, with 32 of them planted across all three sites. At age 3-5 years, the clonal repeatabilities were 0.18-0.42 for growth traits, 0.71-0.78 for wood basic density and 0.56-0.66 for pilodyn penetration. Genotypic correlations between growth and density at the three sites were from -0.24 to 0.17, and did not differ significantly from zero. Genotypic correlations between sites were 0.32-0.56 for growth traits at age 3 years, and 0.72-0.88 for density and pilodyn penetration. Selection gains for breast height diameter at individual sites at a selection proportion of 5% were 22-32%, with minor effects on density. Selection for diameter at one site gave indirect responses in diameter at the other two sites that were only 40-60% of the gains obtainable from direct selection at those sites. This study shows that fast-growing E. camaldulensis clones can be selected in Vietnam with only minor effects on density. Selection for growth should be regionally based to maximize selection gain whereas clonal rankings for density will change little across regions.
Uraiwan Hanchor, Somporn Maelim, Wathinee Suanpaga, Ji-Min Park and Kyu-Suk Kang
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.
M.K. Pagliarini, W.S. Kieras, J.P. Moreira, V.A. Sousa, J.Y. Shimizu, M.L.T. Moraes, E. Furlani and A.V. Aguiar
The study was conducted to estimate the stability, adaptability, productivity and genetic parameters in Slash pine second-generation half-sib families, considering phenotypic traits in early age. Forty-four families from a first generation seed orchard in Colombo-PR, Brazil, were used in this study. Two progenies tests were established in a randomized complete block design. The first test was implemented in March 2009 in Ribeirão Branco, São Paulo state, containing 40 blocks, one tree per plot, 44 treatments (progenies) and 6 controls. Another test was implemented in Ponta Grossa, Paraná state, using the same experimental design and number of plants per plot, and with 24 treatments, 32 blocks. The growth traits evaluated were total height, diameter at breast height (dbh) and wood volume, within five years. The form traits evaluated were stem form, branch thickness, branch angle, number of branches, fork and fox tail five years after planting. Deviance analysis and estimates of stability, adaptability, productivity and genetic parameters were performed using the methods of best linear unbiased predictor (BLUP) and residual maximum likelihood (REML). There was significant variation among progenies for growth and form traits. Considerable genetic variation was detected mainly for wood volume. High coefficients of genetic variation and heritability showed low environmental influence on phenotypic variation, which is important for the prediction of genetic gain by selection. Crosses between different progenies individuals groups will be prioritized for obtaining heterotics genotypes and increase the probability of obtaining high specific combining ability.
Shijun Wu, Jianmin Xu, Guangyou Li, Zhaohua Lu, Chao Han, Yang Hu and Xinxian Hu
Growth traits, wood properties, stem-branch characteristics and bark percentage were assessed for 60 Eucalyptus urophylla S.T. Blake clones in southern China measured at age 21, 52, 71 and 96 months. Analysis of variance showed that there were significant differences on growth traits, wood properties and individual tree wood weight among clones. Coefficients of genotypic variation ranged from 12.12% to 53.16% for growth traits, 9.02% to 20.18% for wood properties, 21.75% to 22.71% for stem-branch characteristics, 28.31% for bark percentage and 51.20% for individual tree wood weight. Repeatability ranged from 0.36 to 0.53 for growth traits, 0.35 to 0.51 for wood properties, 0.21 to 0.24 for stembranch characteristics, 0.07 for bark percentage and 0.31 for individual tree wood weight. The strongly negative genotypic correlations suggesting that selection on growth traits at 21 months can not be effective to predict growth traits at 96 months whereas it could be used to predict growth traits at 52 and 71 months. The genotypic correlations between growth traits and basic density were ranged from -0.78 to 0.28 and weakly positive phenotypic correlations were found between growth traits and basic density, ranging from 0.03 to 0.09. The selection gain on diameter at breast height over bark by different selection proportions at 21, 52, 71 and 96 months old expressed that selection gain at 71 months was some what higher than that at other ages during 10% to 30% selection proportion, while selection gain at 52 months was some what higher than that at other ages during 60% to 90% selection proportion. Wood properties and individual tree wood weight which are strongly related to end production and economically important in pulp production should be studied extensively especially for pulp breeding.
Wanderley dos Santos, Danilla Cristina Lemos Souza, Mário Luiz Teixeira de Moraes and Ananda Virginia de Aguiar
The purpose of this work was to estimate genetic parameters and selection gain of Pinus caribaea var. hondurensis progeny trial for wood and resin production as well as correlation between them. Experiment was established in complete lattice square 10 × 10 (triple), 100 treatments, 10 plants per plot, 3 m × 3 m spacing. Twelve years after planting the trial had thinned considerably leaving six plants per plot. Twenty-seven years after planting height, diameter at breast height (dbh) and resin production were measured. Deviance analysis, genetic parameter estimates, selection expected gain, genetic and phenotypic correlation were based on REML/BLUP method. Significant phenotypic differences were observed among and within families for all traits. The thinning at 12 years after planting, contributed positively to dbh increase and resin production, with an average of 30.60 cm and 4.83 kg tree−1year−1. The individual narrow sense heritability ranged from 0.25 to 0.38 for dbh and volume. Genetic and phenotypic correlation between growth traits were positive, and significant. Therefore, different selection strategies will be proposed separately for both traits (resin and wood). The selection gains were significant, especially with 10 % selection intensity (individual selection) for dbh (7.53 %) and resin (13.49 %). The trial has had good performance for growth, resin and genetic variability to support the next breeding generation
The efficiency of a breeding program depends mainly on the direction of the correlation between yield and its components and the relative importance of each component involved in contributing to seed yield.Twenty one rapeseed genotypes were evaluated based on randomized complete block design with three replications. Significant genotypes effects were exhibited for phenological traits, plant height, yield components except pod length and seed yield, indicating significant genetic differences among the genotypes. High broad sense heritability were determined for phenological traits, plant height and seed yield demonstrating selection gain for improving these traits will be high. Pods on main axis and pods per plant had high value of genetic coefficient of variation and also were significant correlated with seed yield. The results of factor analysis exhibited three factors including first yield components (plant height, pods on main axis and seed yield), second yield components (pods per plant, seeds per pod and 1000-seed weight) and fixed capital factor (phenological traits). On the basis of cluster analysis, the genotypes were classified in three groups and the group with high seed yield had high mean values of plant height, days to maturity and pods per plant.
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D. Torres-Dini, A. C. P. Nunes, A. Aguiar, N. Nikichuk, C. Centurión, M. Cabrera, M. L. T. Moraes, M. D. V. Resende and A. M. Sebbenn
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Hudson CJ, Freeman JS, Myburg AA, Potts BM, Vaillancourt RE (2015) Genomic patterns of species diversity and divergence in Eucalyptus. New Phytologist 206(4):1378–1390. Available at https://doi.org/10.1111/nph.13316
Isik F (2014) Genomic selection in forest tree
Wojciech Król, Ilona Jędrzejewska, Marcin Konopka, Krystyna Burkhard-Jagodzińska, Andrzej Klusiewicz, Andrzej Pokrywka, Jolanta Chwalbińska, Dariusz Sitkowski, Mirosław Dłużniewski, Artur Mamcarz and Wojciech Braksator
, Poland) approved of the study protocol.
Echocardiographic examination was performed by two experienced physicians, using a Vivid 7 machine (GE, Vingmed Ultrasound, Boston, USA), with a M4S 1.5 to 4.0 MHz transducer. ECG was continuously registered. Attention was given to adjust the ECG curve (lead selection, gain control) in order to present a well defined P wave and QRS complex. The examination was performed at rest in the left-lateral decubitus position using standard parasternal and apical views. All echocardiographic acquisitions were digitally stored and off