Guazuma crinita is a semideciduous tree with a narrow, elongate or pyramidal crown; it can grow 7 – 18 metres tall in Brazil, but can exceed 30 metres in Bolivia . PDF | Guazuma crinita (Mart.) is an important timber-tree species for agroforestry plantations in the Peruvian Amazon Basin. Trees are typically. Peruvian smallholder production and marketing of bolaina (Guazuma crinita), a fast-growing Amazonian timber species: Call for a.
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Guazuma crinita is an important fast-growing timber tree species widely used in agroforestry systems in the Peruvian Amazon. The objectives of our research were i to assess genetic diversity of G.
The sample included 44 genotypes from 11 provenances in the Aguaytia and neighboring Pachitea watersheds in the Peruvian Amazon. Ten ISSR primers amplified a total of 65 bands of which 61 were polymorphic The range of DNA amplification varied from to 2, bp. Among the provenances, Macuya exhibited the highest percentage of polymorphic bands PPB with Overall genetic differentiation G jt was 0.
Gene flow Nm was Cluster analysis was not related to geographic origin, suggesting a common gene pool. This is the first study of genetic diversity and structure of G. We recommend in situ conservation strategies for populations with high levels of genetic diversity. A domestication program for tropical tree species started in the mids in the Peruvian Amazon, and identified Guazuma crinita Mart.
Sterculiaceae family as one of the priority timber species for agroforestry systems So-telo-Montes and Weber This pioneer species can be inter-cultivated with food crops because it has a small crown with thin branches, and the older branches naturally self-prune in the lower crown.
It provides wood products at an early age yearscan be coppiced for successive harvests and contributes significantly to farmers’ income Labarta and Weber Due to its fast initial height growth up to 3 m per year it has also been promoted in reforestation programs and agroforestry systems IIAP The mating system of G.
Trees can begin flowering after years and produce millions of seeds that are dispersed by both wind and water at the beginning of the rainy season Rochon et al. The species can potentially produce a dense stand of natural regeneration in open patches Rochon et al. Its importance has prompted research to identify the best provenances and improve the management of the species.
Guazuma crinita Images
In general, very little research on intra-specific genetic variation in agroforestry tree species in the tropics has been reported Weber and Sotelo-Montes Genetic variability is essential to the success of strategies for tree improvement including selection, sustainable management and genetic resource conservation O’Neill et al.
Morphological characters and commercial wood traits have been used traditionally to characterize levels and patterns of diversity; however these traits alone represent only a small portion of the plant genome and are also influenced by environmental factors Muchugi et al.
The use of genetic markers based on DNA overcome these disadvantages and are able to measure the genetic diversity in plant species White et al. Inter Simple Sequence Repeat ISSR markers combine some advantages of other markers such as reproducibility, low costs and no need to develop species-specific primers for analysis. ISSRs are an efficient tool to rcinita the variability and genetic structure in natural, managed and cultivated tree stands, and are useful to identify genotypes, even among highly crinitz individuals Thangjam The objectives of this research are i to assess genetic diversity of G.
We hypothesized that there is a high level of polymorphism within provenances, very little differentiation among provenances and a positive relationship between genetic distance and geographic distance among provenances.
Sample origin and plant material. We analyzed 44 genotypes of G. They were identified and selected based on phenotypic measurements along ten years of evaluation. Young leaf tissue samples of each genotype were individually collected and stored in micro-test tubes with silica gel for further DNA isolation. Map of collection areas of 11 provenances that were sampled in the study.
Puerto Inca and Guazuna DNA quality was determined by 0. Among the 30 universal UBC-ISSR primers University of British Columbia, Canada tested ghazuma their crijita to produce distinct, reproducible and well-resolved fragments in the 44 individual genotypes, 10 primers were selected for the amplification of all the samples table 2.
Primers used in xrinita ISSR analysis and crinia of amplifications. The cycling conditions were as follows: PCR amplification of the samples cdinita each primer was carried out in duplicate so as to ensure the consistency and reproducibility of the results.
ISSR fragments were scored as presence 1 or absence 0 of bands in the gel profile.
Only strong bands were used to construct a binary matrix. A dendrogram was constructed by unweighted neighbor joining based on Jaccard’s dissimilarity index.
Mantel test in Gen Al Ex V6 Peakall and Smouse was performed using Nei’s unbiased genetic distances matrix and the matrix of geographic distances to determine whether the geographical and genetic distances between provenances were correlated.
The DNA amplified using ISSR markers generated a total number of 65 fragments by the ten primers; the amplified fragments were within a range of to 2, bp. A total of 61 fragments were polymorphic The average guazima of loci and polymorphic loci generated per primer were 6. The overall analyses of genetic variation at watershed and provenance level are shown in table 3.
The percentage of polymorphic bands was higher in Aguaytia watershed, while Nei’s gene diversity He and Shannon guzauma I were higher in the Pachitea watershed. Tournavista-road also had the lowest Nei’s gene diversity He and Shannon index I. Overall coefficient of genetic differentiation G st was 0.
Gene flow Nm was estimated to be An analysis of Nei’s genetic identities of the pair-wise comparison between provenances varied from 0. Genetic distances among provenances ranged from 0. The lowest genetic distance was between Nueva Requena ANR and Curimana river ACR provenances which are both located along the Curimana river figure 1suggesting that downstream dispersal of seeds reduces the genetic distance. However, the genetic distance was relatively low between most provenances in the Aguaytia watershed and Macuya, which is in the Pachitea watershed figure 1.
It may reflect the exchange of genes by the influence of human activity along closer watersheds. Nei’s genetic distance and geographic distance among the provenances of G. Geographic distance in kilometers above diagonal and Nei’s genetic distance below diagonal. See table 1 for provenance abbreviations. In order to assess relationships among provenances, a cluster analysis was used to generate a dendrogram based on Jaccard’s dissimilarity among the 44 genotypes figure 2.
Guazuma crinita Images – Useful Tropical Plants
The dendrogram showed that the genotypes were grouped into three distinct clusters. Topology of the dendrogram showed that clusters were not related to the geographic origins of the genotypes. Dendrogram of 44 Guazuma crinita genotypes based on Jaccard’s dissimilarity index. This suggests that geographic distance had a small effect on genetic differentiation among provenances. Tree domestication has evolved over the last two decades to become an important global program, and molecular techniques have been used to analyze genetic diversity in several agroforestry tree species Leakey et guazima.
A number of authors have examined both natural stands of tropical trees and cultivated samples e. Results huazuma the guazu,a test indicated that the provenance from the local watershed Aguaytia performed better in terms of growth than did gguazuma from other watersheds in the Peruvian Amazon Basin Weber and Sotelo-Montes Wood density also varied genetically among provenances Weber and Sotelo-Montes In this study of 44 genotypes from 11 provenances of G.
Although we were aware that our sample size was not extensive limitation caused by small number of individual trees in the clonal orchardother researchers have investigated genetic diversity in tree species using even smaller sample sizes e. Our study revealed For example, Russell et al.
However He of G. The high value for gene flow reflects both pollen dispersal and seed dispersal. Seeds can be dispersed over long distances by wind, and also downstream by water, hence we expected little differentiation among provenances.
This is similar to the case of C. There was a weak positive relationship between geographic and genetic distances of the provenances. However, the cluster analysis did not reveal any clear geographical pattern among the genotypes from the different provenances. Cluster groups, contained genotypes from several different provenances.
These results probably reflect the high gene flow in the sample region or limitation of the ISSR markers to reveal the existing variation among provenances. Results suggest that the provenances populations of G.
The dynamic of gene flow via rivers within and among watersheds in the Peruvian Amazon Basin Jansky and forest fragmentation due to shifting cultivation could contribute to the formation of subpopulations Dourojeanni A report of genetic differentia tion of Swietenia macrophylla King.
Most diversity occurred within rather than among provenances. It seems that, there exists extensive gene flow, thus the provenances were not genetically isolated. There was no clear grouping of genotypes cirnita on the genotypes’ provenance of origin or proximity to other drinita. Nevertheless, there was a weak positive correlation between genetic and geographic distance of the provenances. Our results confirm that even a small clonal garden that was used in our research –under the conditions that the collection be correctly done– could possess relatively high genetic diversity and thus could form a good base for further domestication of the species.
In addition to ex situ clonal gardens, in situ conservation of populations of G. Since seeds are dispersed by rivers downstream, we vuazuma expect higher genetic diversity below the confluence of major rivers, consequently targeting conservation in these areas may be an effective conservation strategy.
This study indicates that ISSR markers are effective and a relatively easy way to detect polymorphism and characterization of genetic variation. However, we recommend analyzing more samples per population with employment of other types of molecular markers in future studies of genetic diversity as a basis of genetic improvement to G.
The authors thank Manuel Soudre for providing access to the clonal garden and information about crinifa genotypes of G. The authors thank Joel Odicio for support with the molecular markers analyses.
Tree origins and conservation on farm: A rapid DNA isolation procedure for small quantities of fresh tissue. Documento de trabajo No. Genetic variation in Costa Rica populations of the tropical timber species Cedrela odorata L.
Do farmers reduce genetic diversity when they domesticate tropical trees?