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Short Note: Cleistogamy in Eucalyptus tereticornis Sm. and its Genetic Implications

Abstract

In a provenance cum progeny trial comprising 13 provenances and 91 families of Eucalyptus tereticornis Sm. of Australian and Papua New Guinean (PNG) origin, laid out in India in 2002, cleistogamy was found in a family emanating from CSIRO seed lot no. 13418, (tree no. DS000141) Sirinumu Sogeri Plat, PNG. This trait appears to be under genetic control, and presumably results in obligate selfing. This may lead to inbreeding depression in this family.

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Parental and Consensus Linkage Maps of Eucalyptus globulus Using AFLP and Microsatellite Markers

, M., M. I. MARQUES-GARCIA, T. UREN, D. S. SMITH and G. F. MORAN (1996): Conservation and genetic diversity of microsatellite loci in the genus Eucalyptus. Australian Journal of Botany 44: 331-341. CARNEGIE, A. J., P. J. KEANE, P. K. ADES and I. W. SMITH (1994): Variation in susceptibility of Eucalyptus globulus provenances to Mycosphaerella leaf disease. Canadian Journal of Forest Research 24: 1751-1757. CERVERA, M. T., C. PLOMION and C. MALPICA (2000): Molecular markers and genome mapping in woody plants, pp. 375-394. In: Molecular

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Genetic Variation in Frost Damage and Seed Zone Delineation within an Altitudinal Transect of Pinus devoniana (P. michoacana) in Mexico

Abstract

We explored the patterning of genetic variation among Pinus devoniana Lindl. (also known as P. michoacana Martínez) populations to develop guidelines for seed and seedling movements, intended for improving the matching between genotypes and environments regarding frost tolerance, in reforestation programs. Open-pollinated seed from 16 populations along an altitudinal transect (1600 to 2450 m) were collected near Morelia, State of Michoacán, México. A common-garden provenance test, established with 2.5-year-old seedlings, was assessed for frost resistance conducting a laboratory frost damage test (-9°C). Results indicate that there were significant differences among provenances (P = 0.0261) for frost damage. Variation among provenances was structured as an altitudinal cline, with populations from lower altitudes being the least tolerant to frost. Linear regression statistics suggest that for each increment of 100 m of provenance altitude, there will be a 5.2% decrease in frost damage. We suggest the use of two provisional altitudinal seed zones of 400 m breadth each (lower and upper limits for zone 1: 1600 m and 2000 m of altitude; for zone 2: 2000 and 2400 m, respectively), and for reforestation of a given site, the use of seedlings originated from seed of the same seed zone or within ±200 m of altitude from the elevation of the reforestation site.

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Interspecific Differences in Postharvest Quality on Mexican Christmas Trees

Abstract

There are no comparative studies in postharvest quality of Mexican Christmas trees. The objective of this study was to identify the best postharvest performing Mexican cultivated species. The experiment was done in the 2004-2005 season with six replications (trees) of Abies religiosa, Cupressus lindleyi, Pinus ayacahuite, and Pseudotsuga menziesii; from two provenances (Tlaxcala and Veracruz) for the last two species. Cultural management was similar. Each tree was placed under dry conditions according to a completely randomized design. Secondary branches, twig diameter and density, initial and final weight, biomass allocation, areas and volumes, total and twig moisture content, foliage density, color, chlorophyll a/b ratio, CO2 and ethylene production were evaluated. Analyses of variance, comparisons of means, correlation, and simple regression were performed. The four studied species displayed undesirable characteristics. Genetic improvement is required. P. menziesii showed values nearer ideotype breeding in more variables. The best provenance was Tlaxcala. Several correlations between variables showed tradeoffs in selecting the best species.

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Genetic Variation in Reproductive Traits in a Clonal Seed Orchard of Prunus avium in Northern Spain

Abstract

In the present study we investigated the reproductive phenology of Prunus avium in a seed orchard located in northwestern Spain. The study was carried out with 103 clones from 7 provenance regions in northern Spain. The most advanced flowering stage on different dates and the number of flowers and cherries were monitored over two consecutive years. Significant differences among clones were found for all of the studied traits, with high broad-sense heritability estimates for all, except duration of flowering and synchronization index, both of which showed moderate heritability. In general, there was good overall reproductive synchronization in the seed orchard, although two groups of clones were differentiated. Clones from two out of the seven populations studied flowered later and were less well synchronized. The clonal differentiation was correlated with geoclimatic variables, suggesting that clones from lower altitudes and higher temperatures tend to an earlier flowering.

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1. A genetic linkage map of Pinus massoniana based on SRAP, SSR and ESTP markers

Abstract

Pinus massoniana (masson pine) is the most important native pine in southern China. High-density genetic maps have not been constructed for the species. In this study, a genetic linkage map with 251 markers (47 SSRs, 23 ESTPs and 181 SRAPs) was constructed using a F1 progeny mapping population derived from controlled pollination of two parents of different provenances. At LOD 7.0, a total of 17 linkage groups were constructed with twelve groups having nine or more markers and five other groups of two to four markers each. The total map length was 1,956 cM with an average of 8.4 cM among individual loci. The current linkage map represented 93% of the estimated genome length of 2,114 cM for masson pine. Such linkage map are useful for future genomic studies of masson pine including comparative mapping in Pinaceae and quantitative trait loci (QTL) mapping for economically important traits.

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Three microsatellite multiplex PCR assays allowing high resolution genotyping of white spruce, Picea glauca

Abstract

Fifteen previously published microsatellite primer pairs developed for and tested on Canadian white spruce were screened for amplification and polymorphy in Alaskan populations and tested for their suitability in PCR multiplexing. Eleven loci expressing polymorphisms ranging from 7 to 58 alleles were selected for development and optimization of three multiplex assays. Four natural stands containing a total of 1470 trees were used to characterize the selected loci and demonstrate their applicability for genotyping studies and parentage analysis. These assays can be used for studies focusing on population genetics, parentage analysis, provenance research, or individual genetic fingerprinting. The use of multiplex PCR facilitates large-scale studies by simultaneously enabling high resolution and reducing processing time and per sample cost.

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Comparison of Genetic Structure Assessed by Amplified Fragment Length Polymorphism and Retrotransposon-based Sequence-specific Amplification Polymorphism for Portuguese Populations of Pinus pinea L.

Abstract

In order to assess genetic diversity within and among populations of Pinus pinea L. (stone pine), seven Portuguese populations originating from three Provenance Regions were selected and genotyped using two marker systems. We compared the genetic variation of these populations using retrotransposon-based sequence-specific amplification polymorphism (SSAP) and amplified fragment length polymorphism (AFLP). In total, 105 trees were screened with three primer enzyme combinations (PEC), producing 232 SSAP and 132 AFLP loci. Where SSAP yielded approximately twice-the number of polymorphic fragments compared to AFLP. Differentiation was slightly higher for SSAP, than for AFLP (FST = 0.105 for SSAP and 0.074 for AFLP), and both significantly different from zero, P < 0.01. The levels of average genetic diversity within-population found with the two types of marker were not significantly different between SSAPs and AFLPs (26.6% and 22.8%, respectively). The populations that displayed the highest and lowest genetic diversity scores were the same for both markers, and only two populations had significantly different He estimates. The neighbor-joining tree based on the Nei’s genetic distance displayed some geographic pattern. With the AFLP markers the populations grouped according to the provenance regions where they were sampled, resulting in one well supported cluster with the Southern populations, but with SSAP the pattern was not so coherent. In this study SSAP generated more polymorphic fragments and higher estimates of genetic diversity than AFPL did, due, probably, to the higher mutation rate of retrotransposition relative to base mutation. Nevertheless, congruence was found between estimates obtained with both markers, which is very interesting, for, in general, SSAP markers have lower costs compared to AFLPs, and they might be an interesting alternative marker system, when higher resolution is requested.

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Crossability of Pinus sibirica and P. pumila with their hybrids

Abstract

Crossability of Pinus sibirica and P. pumila hybrids and their parental species was studied using the controlled pollination method. Pinus sibirica and its hybrids were represented by grafts at the “Kedr” field station southeast of Tomsk Oblast, Russia; the parental species was of local provenance, with its hybrids obtained from the Southern Baikal region. In the case of P. pumila, trees were pollinated in a wild stand located in the Upper Angara River delta. Parental species had the highest number of filled seeds under open pollination. When they were pollinated with hybrid pollen, the trees showed nearly two-fold reductions in the number of filled seeds. Hybrids tended to abort most ovules during the first year of female cone development, resulting in a high seed abortion rate and consequent low seed production. The number of filled seeds obtained from hybrids was low, with levels ranging from 8.2 to 24.3%. Because of weak reproductive isolation between hybrids and parental species, crosses are inevitable and lead to species introgression. The hybrids probably contribute to interspecies genetic exchange both through hybrid seed production following pollination by parental species and by hybrid pollen distribution.

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Differentiation of six Eucalyptus trees grown in Mexico by ITS and six chloroplast barcoding markers

Abstract

Different species of the genus Eucalyptus, originally native to Australia, are being cultivated in different parts of the world due to their fast growth and beneficial wood properties. In Mexico, probably up to 25 different Eucalyptus species (many of them with unknown species declaration) were introduced early in the 20th century. Many Eucalyptus species are cross compatible and information about provenances of the single eucalypt species is rare. In this study, an experimental plantation established in 1984 and located in Northeast of Mexico was chosen as example to re-assign the species name of six randomly selected Eucalyptus trees growing in this plantation. First, a phylogenetic tree was constructed from complete chloroplast sequences of 31 Eucalyptus species available in the NCBI database. The phylogenetic tree includes three of the nine Eucalyptus species known to be introduced to Mexico, namely E. camaldulensis, E. saligna and E. grandis, which belong to a clade named “Symphyomyrts”. By employing combined BLASTN and UPGMA analyses of six chloroplast (cp) regions, three of the six unknown eucalypt samples (Euc4, 5, 6) cluster together with E. microtheca and E. cladocalyx, whereas the other three (Euc1, 2, 3) were more similar to a group containing E. camaldulensis, E. grandis and E. saligna. UPGMA analysis of the ITS region overall shows the same rough clustering, but provide more detailed information for two samples being most likely assigned to E. camaldulensis.

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