bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polyploidy in Gymnosperms: Revisited
Authors: Ahuja M. Raj 
Published: October 2017

AbstractThere are only a few natural polyploids in gymnosperms. These have been reported in Ephera spp. (Gnetales), and Juniperus chinensis ‘Pfitzeriana’ (2n = 4x = 44), Fitzroya cupressoides (2n = 4x = 44), and the only hexaploid conifer Sequoia sempervirens (2n = 6x = 66) (Coniferales). Sporadic polyploids and aneuploids occur at a very low frequency in nurseries in conifers, but most of them show growth abnormalities, remain dwarf, and may not reach maturity. One exception is an autotetraploid tree of Larix decidua (2n = 4x = 48) that has survived in a private estate in Denmark. Colchicine-induced polyploids (colchiploids) have been produced in a several genera of conifers, including, Pinus, Picea, and Larix. These colchiploids (Co) were hybridized to untreated diploids to produce C1 and C2 generations to investigate their chromosome behavior. The colchiploids showed a wide range of chromosome variability, ranging from diploids, triploids, and tetraploids, and many were mixoploids. The colchiploids also show growth retardation, remain dwarf, and their future potential applications in forestry remains uncertain. However, genetic variability in the colchiploids still offers prospects for isolating genetically stable new genotypes. Even though polyploidy is rare in extant conifers, is it possible that ancient polyploidy or paleopolyploidy, that is prevalent in angiosperms, has also played a role in the evolution of conifers. In this paper we shall review the current status of polyploidy in gymnosperms.
Genetic Variation and Realized Genetic Gain From Black Pine Tree Improvement
Authors: Matziris D. 
Published: October 2017

SummaryIn 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.
Impact of Clones in a Clonal Seed Orchard on the Variation of Seed Traits, Germination and Seedling Growth in Santalum album L.
Authors: Annapurna D. , Rathore T. S , Somashekhar P. V. 
Published: October 2017

SummaryClonal Seed Orchard (CSO) of Santalum album L. at Nallal, India consisting of 25 clones originated from different agro-climatic conditions of four southern states (Karnataka, Tamil Nadu, Kerala and Andhra Pradesh) was source of seeds for variability studies. There was vast variation in seed size, weight, germination, vigour and seedling growth of different clones over the years. Seed length, width and weight were positively correlated to each other but seed size had no effect on germination, Germination Value (GV), days taken for germination and early seedling growth. Effects of Clones were dominant and accounted for variation in germination rather than seed size. There was no consistency in the parameters studied in the two years. The impact of these genetic differences in handling of seed lots during bulking, grading and storage for mass propagation of nursery planting stock of S. album is also discussed.
Early Assessment of First Year Height Data from Five Acacia mearnsii (black wattle) Sub-populations in South Africa using REML/BLUP
Authors: Dunlop R. W. , Resende M. D. V. , Beck S. L. 
Published: October 2017

Abstract
Recent research has shown, Acacia mearnsii (black wattle) to be a source of high quality pulp. This led to a change in the emphasis in the breeding programme at the Institute for Commercial Forestry Research, from improving bark yield and quality, to improving timber yield and quality while maintaining an acceptable bark quality. A Multiple Population Breeding Strategy was implemented to cater for these changes. Five sub-populations were established across different sites in KwaZulu- Natal and were determined by origin of seed. Each sub-population was established as a progeny trial with a seedling seed orchard adjacent to it. The management of the seed orchards will be determined according to the performance of the families within the progeny trials. This paper reports on the first year height measurements taken from the five sub-populations. The intention of this paper is not to base any selections from this data but rather to establish a set of analyses using REML/BLUP which will be used for future data analysis. This will also allow for future assessment of age-age correlations for the various traits being assessed and provide an appropriate decision-making tool, for selecting individuals for future generations.
Cone Yield Characterization of a Stone Pine (Pinus pinea L.) Clone Bank
Authors: Mutke S. , Gordo J. , Gil Luis 
Published: October 2017

Abstract
In spite of the use of the edible kernels of Stone pine (Pinus pinea L.) gathered from Mediterranean pine forests, the species remains a genuine forest tree that has never been domesticated as an orchard crop. In the last decades, some efforts have been made to select valuable genotypes for exploring the possibilities of Stone pine as an orchard crop. The present paper characterizes the cone yield of a grafted clone bank in order to elucidate the relevance of genetic and environment factors for seed-yield quantity and quality and for sequential transition rates of the development from pollinated conelets to ripe cones. Individual tree size and cone yield were separated in their genetic and environmental components, in order to estimate phenotypic, genetic and environmental correlations. A statistical model for logtransformed individual cone yield was adjusted, ranking the tested genotypes by their estimated clonal value after adjustment for tree size covariables. The degree of genetic determination for adjusted cone yield was estimated in 15%, the expected genetic gain by selection of the top 10% of tested genotypes would be 12%. Genetic correlation between genetic values for cone yield and cone and seed size were weak but significantly positive (r = 0.27 and 0.17), hence the lack of trade-offs between crop quantity and quality will allow a combined selection.
Variation in Reproductive Phenology in a Pinus radiata D. Don Seed Orchard in Northern Spain
Authors: Codesido V. , Merlo E. , Fernández-López J. 
Published: October 2017

SummaryReproductive phenology was studied in a Pinus radiata seed orchard, located in northern Spain. Timing of flowering was determined on the basis of data recorded by visual observations made in 2000, 2001 and 2002. The genetic and environmental factors affecting female and male phenology, as well as reproductive synchronization, were studied. The dates of beginning of the receptive phase and pollen shedding varied greatly from year to year but the variation on the sum of degree-days was low. In general, the flowering periods of the different clones overlapped. The clonal differences in the phenology of receptivity and pollen shedding were in most cases statistically significant. The time needed to reach flowering stages was under strong genetic control. Genetic control was stronger for the female than the male flowering process. However, correlations between years were stronger for male than for female flowering phenology. The male flowering clones that best synchronized with the females appeared to be those that started flowering earlier. The phenological overlap index varied greatly among clones, whether male or female, and also among years.
Contrasting Quantitative Traits and Neutral Genetic Markers for Genetic Resource Assessment of Mesoamerican Cedrela Odorata
Authors: Navarro C. , Cavers S. , Pappinen A. , Tigerstedt P. , Lowe A. , Merilä J. 
Published: October 2017

Abstract
We compared within-population variability and degree of population differentiation for neutral genetic markers (RAPDS) and eight quantitative traits in Central American populations of the endangered tree, Cedrela odorata. Whilst population genetic diversity for neutral markers (Shannon index) and quantitative traits (heritability, coefficient of additive genetic variation) were uncorrelated, both marker types revealed strong differentiation between populations from the Atlantic coast of Costa Rica and the rest of the species’ distribution. The degree of interpopulation differentiation was higher for RAPD markers (FST = 0.67 for the sampled Mesoamerican range) than for quantitative traits (QST = 0.30). Hence, the divergence in quantitative traits was lower than could have been achieved by genetic drift alone, suggesting that balancing selection for similar phenotypes in different populations of this species. Nevertheless, a comparison of pair-wise estimates of population differentiation in neutral genetic markers and quantitative traits revealed a strong positive correlation (r = 0.66) suggesting that, for C. odorata, neutral marker divergence could be used as a surrogate for adaptive gene divergence for conservation planning. The utility of this finding and suggested further work are discussed.
Comparison of Phenotype and Combined Index Selection at Optimal Breeding Population Size Considering Gain and Gene Diversity
Authors: Li H. , Lindgren D. 
Published: October 2017

Abstract
A breeding program was simulated in this study. Two alternative ways of selecting the breeding population for the following generation was compared. Phenotypic selection, which means to select just on the individual performance, and combined index selection, which means selection on predicted breeding value for each individual obtained by weighting family average and individual phenotype, were compared. The plant number (testing resource) and gene diversity (status number, Ns) were kept constant, but the breeding population size was variable and chosen for maximizing gain for the particular breeding scenario. At low and medium heritability phenotypic selection was inferior to combined index selection. Only when heritability was high phenotypic selection was as efficient (generation 1) as or more efficient (generation 5) than combined index selection. This contrasts to earlier studies done under constant breeding population size, where selection methods appeared similar. The advantage in gain of combined index selection is usually at a larger breeding population size. At limited heritability and breeding population size the difference is considerable. When breeding population size was kept rather small (<100), and the heritability limited, combined index selection can result in slightly higher gain than phenotypic selection at the same gene diversity, but this was at the cost of a much larger breeding population. Phenotypic selection and combined index selection appears as rather similar for many cases in this simple model used in this study. Considering other advantages with phenotypic selection, it may often be regarded as a competitive alternative.
Phylogenetic Relationship Within Genus Araucaria (Araucariaceae) Assessed by Means of AFLP Fingerprints
Authors: Stefenon V. M. , Gailing O. , Finkeldey R. 
Published: October 2017

Abstract
Highly polymorphic AFLP markers were applied to analyse the phylogenetic relationships of seven species from three sections within genus Araucaria (Araucariaceae) with cladistic and phenetic approaches. The objectives of the study were to compare the intrageneric relationships within Araucaria assessed by AFLP markers with the classification according to chloroplast DNA sequences and morphological characters. The AMOVA revealed 48% of the variation among species. The results of the principal coordinate analysis revealed three distinct groups: (1) A. angustifolia and A. araucana (= section Araucaria), (2) A. bidwillii (= section Bunya) and (3) A. cunninghamii, A. heterophylla, A. rulei and A. scopulorum (= section Eutacta). In the cladistic and phenetic analyses, phylogenetic trees were subdivided into two sister clades, one comprising the samples from section Eutacta, the other one was divided again into two sister clades corresponding to sections Araucaria and Bunya. These results are congruent with a previous phylogenetic study of the family Araucariaceae based on rbcL sequences and with the classification of genus Araucaria based on morphological characters. Both rbcL sequence data and AFLP analyses do not support section Bunya as one of the oldest sections within genus Araucaria, as suggested by the fossil record. The utility of AFLP markers for phylogenetic analyses is discussed.
Estimating Genetic Parameters for Wood Density of Scots Pine (Pinus sylvestris L.)
Authors: Fries Anders , Ericsson Tore 
Published: October 2017

Abstract
Wood density was analysed and annual ring width was measured on increment cores from 1400 trees in a 30-year-old full-sib progeny test of Scots pine (Pinus sylvestris L.) in north Sweden. Genetic parameters for wood density were analysed separately for ten outer annual rings, and for simple averages of the five most recent years. The evaluation included genetic correlations with height and stem diameter. Heritabilities of density estimated separately for each annual ring was 0.14-0.26 without any age trend, and jointly for the ten or five latest rings 0.30-0.33; for height growth it was 0.30-0.42 and for stem diameter 0.11-0.13. Additive genetic correlations with height and stem diameter were negative with the simplest statistical model (ȓA = -0.425 and 0.511, respectively) but vanished or diminished when ring width was added as covariate. Density breeding values calculated for the parent trees for each of ten annual rings separately varied considerably between parent trees and between years, tending to increase with increasing age, with a substantial increase between the ages 14 to 16 years from the pith. This age fits well with literature data on the change from juvenile to mature wood. The genetic correlation for wood density between rings from different years was high: ȓA = 0.8 ten years apart, increasing to 1.0 for neighbouring rings. The high genetic correlations for wood density between the innermost and outermost annual rings indicate possible strong covariation between juvenile and/or transition wood and mature wood. The annual variation in wood density in relation to genetic regulation, phenology, environmental conditions, and development from juvenile to mature age is discussed.
Cytogenetic Effect of Radiation in Seed of Oak (Quercus robur L.) Trees Growing on Sites Contaminated by Chernobyl Fallout
Authors: Kalaev V. N. , Butorina A. K. 
Published: October 2017

Abstract
The Chernobyl accident was one of the largest man made environmental disasters and had significant consequences for people, animal and plants, particularly on land contaminated by radionuclides. Common oak (Quercus robur L.) is the main forest species on land contaminated by Chernobyl fallout areas in the Voronezh region. Therefore it is very important to know how irradiation of oak trees will affect the quality of oak progeny in future consequently. Cytogenetic characteristics such as mitotic activity, level and spectrum of mitotic disturbances, frequency of the cells with persistent nucleoli in the stages of metaphase, anaphase, telophase and multinuclei in interphase cells were investigated in progeny of common oak (Quercus robur L.) trees subjected to different degrees of radioactive contamination. In progeny growing under the influence of this radioactive contamination we observed variability of such cytogenetic characteristics as mitotic activity. However, the variability of this trait was also connected to fluctuations in the weather. The duration of mitotic stages (which may be connected with disturbance of spindle division formation and absence of cytotomy) also varied. An increase in chromosomal bridges among other types of mitotic abnormalities may be considered a result of increases in the meristematic cells repair activities. Activity of some dormant nucleolus organizer regions was also observed. The level of pathological mitoses increased in particular years and was decreased in others. Thus irradiation induces instability of cytogenetic characteristics in oak progeny that produces a type of “wave kinetics” in the mutation rate. This makes them more sensitive to environmental conditions. Therefore we do not recommend to use the oak seeds collected from irradiated areas for reforestation because undesirable genetic changes may have occurred in them.
Genetic Diversity and Gene Flow of Quercus crispula in a Semi-Fragmented Forest Together With Neighboring Forests
Authors: Ohsawa Takafumi , Tsuda Y. , Saito Y. , Sawada H. , Ide Y. 
Published: October 2017

AbstractThe genetic diversity and differentiation in Quercus crispula populations in the Chichibu Mountains, central Japan, were evaluated using six microsatellite markers. Gene flow into a 2500-m2semi-fragment of a natural forest from the neighboring natural forest at a distance of more than 50m was also evaluated using parentage analysis. All five populations in the mountains had similar levels of genetic diversity (He= 0.752-0.792), and the level of population differentiation was low (FST= 0.016). The semi-fragmented stand showed similar genetic diversity with the neighboring unfragmented forests, and Hardy-Weinberg disequilibrium was not found (FIS= 0.083 in adults, 0.025 in seedlings). In the semifragment, 70 seedlings were examined; according to the parentage analysis, eight of the 70 seedlings (ca. 11%) had neither of the parent trees in this fragment. These seeds must have been transported from a distance of more than 50 m; therefore, there could be a possibility that the seeds were dispersed by birds. A similar trend of seed flow into the fragment was also confirmed by genotyping endocarps of hypogeal cotyledons, while more frequent seed flow was found in the neighboring unfragmented forest. Of the remaining 62 seedlings, the maternal trees (but not the paternal trees) of 29 seedlings and both parent trees of 33 seedlings were detected in the semi-fragment. These results indicate that the gene flow among the populations occurs frequently via pollen dispersal and occasionally via seed dispersal and that, at least the current levels of genetic diversity have been maintained in such fragmented forests.
Comparison Between Open Pollinated Progenies and Hybrids Performance in Eucalyptus grandis and Eucalyptus urophylla
Authors: Bison O. , Ramalho M. A. P. , Rezende G. D. S. P. , Aguiar A. M. , Resende M. D. V. De 
Published: October 2017

SummaryThe cellulose industry in Brazil uses, mainly, hybrids between Eucalyptus grandis × E. urophylla. Not only the volume but also the wood density has great influence in the cellulose productivity, therefore a selection for both characteristics should be done as an alternative to increase the improvement program efficiency. The present work has been carried out with the objective of comparison between Open Pollinated progenies (OP) and hybrids performance in E. grandis and E. urophylla. To do so, 15 OP progenies of E. grandis, 15 OP progenies of E. urophylla, and 15 hybrids between E. grandis × E. urophylla, plus four controls were evaluated. The experiment was carried out from October to November 2001, in three sites, Aracruz and São Mateus, in the Espírito Santo State, and Caravelas, Bahia State, Brazil, in a 14 × 14 lattice design, involving the 49 treatments mentioned plus other progenies not considered in this article, with single tree plots and 40 replicates. Two years later the circumference at breast height (CBH) and the basic wood density (BWD) were evaluated. The hybrids performance for CBH was higher, an average, 38,7% than the OP progenies for both species. Part of the heterosis in relation to parental means could be attributed to the inbreeding depression due to selfing that occurred in the OP progenies and the dominance controlling this character. For the BWD the hybrids performance was the same of the OP progenies. Since there was divergence between the parents, it can be inferred that dominance has no importance for this trait. The negative correlation between the CBH and the BWD could impair the simultaneous selection for both traits, depending on the wood basic density range used by the industry.