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Genetic variation and clonal propagation of superior genotypes of selected Acacia species
Full text linkThe Acacia species was introduced into Malaysia in the late 1960’s for timber
production. Plantations of Acacia species gain interest as a major timber species in the
1960’s especially in Peninsular Malaysia along with Hevea brasiliensis. The product
in forestry ventures is often sawn timber, which requires trees to be in good conditions
such as straight, single-stemmed and defect-free trunks for maximum utilization.
Production of such quality wood is another big problem in forestry plantation since
trees grown in plantation of some high-value temperate and tropical hardwood species
tend to produce low value, short butt logs and bolts due to crooked stems, low fork
heights and delayed shedding of lower branches.
In this context, a research study was initiated to select and recommend the best
performing tree species or provenances suited for timber production in Malaysia with
respect to growth and other characteristics. Species/provenance/progeny test was
conducted on four species of Acacia namely, A.mangium, A.auriculiformis,
A.crassicarpa and A. aulococarpa with four provenances for each species from two
main regions of Papua New Guinea and Queensland. The growth of the provenances
was monitored in terms of some quantitative and qualitative characteristics to evaluate
the genetic variation and growth performance of a base breeding population. The study
showed that there were significant differences (p< 0.05) between species, provenance
and progenies for their growth performance. There were also significant differences
between provenances within regions and progenies within provenances in all
quantitative and qualitative traits tested in this study.
Generally, with regard to the growth, A.mangium performs better compared to other
Acacia species in all of the aspects tested and it was followed by A.crassicarpa,
A.aulococarpa and A.auriculiformis. Generally provenances and progenies selected
from Papua New Guinea excelled those from Queensland both in quantitative and qualitative characteristics. Among the top performing progenies of Acacia species are
CG 1854 of (Bensbach WP) and KN000107 (SW of Boset WP) of A.mangium,
BVG2609 (Bensbach WP) of A.crassicarpa, BVG 00835 (WP Morehead) and
MM1016 (Arufi E Morehead WP) of A.aulococarpa and JSL363 (Wenlock River) and
BVG 2657 (Bansbach) of A.auriculiformis.
Three best performing clone (genotypes) were then chosen based on their phenotypic
characteristic for clonal propagation of superior tree species through traditional and
modern techniques. Vegetative propagation was attempted as initial pretreatment
stage of rejuvenation of mature sources through forced flushing, stem cuttings and
trunk decapitation. A. mangium and A. auriculiformis respond well to force flushing
by having highest survival percentage (87.7% and 90%, respectively) together with
bud breaking and sprout growth. Whereas, A.aulococarpa and A.crassicarpa only
recorded 52.2% and 31.1% of survival percentage. Rooting ability of stem cuttings,
feasible and mean root number and root length increase at juvenile stage for all species
studied. Rooting ability of mature cuttings decreased and bud breaks occurred only for
few days eventually died, and did not respond to the treatments of growth regulators.
Rooting ability of young stem cuttings of A. mangium (83.3%) and A.auriculiformis
(76.6%) was better compared to that of A.crassicarpa and A aulococarpa with only
48% and 68.8%, respectively. Investigation was also done for the use of coppice
materials as an alternative source for in vitro propagation of mature sources. 12 yearold
trees of selected Acacia species were felled to the height of 1.0m and 1.5m.
Vigorous production of sprout or coppice was noted on the stumps of trees of all
species except of A.crassicarpa. The greatest copping ability in terms of survival rate
of stumps was observed on A.auriculiformis with 83.8% followed by, A.mangium,
A.aulococarpa and A.crassicarpa with 75.0%, 40.0% and 1.67 %, respectively.
A.crassicarpa produces a very low number of sprouts with mean of 0.03 and mean of
0.09 for sprout length.
Rejuvenated mature explants were further subjected to in vitro conditions for mass
production of improved materials for establishment of efficient in vitro protocol for
Acacia sp. Decontamination of field collected materials was conducted as an initial
stage in shoot initiation stage using some methods optimized in preliminary study.
Most effective sterilization in term of average clean culture percentage (>70%) was
recorded in 0.1% HgCl2 for 5 minutes for A.mangium, A.auriculiformis, A.mangium
‘Superbulk’ and A. hybrid and 0.1% HgCl2 for 10 minutes for both A.crassicarpa and
A.aulococarpa. Incorporation of 0.1g/l of fungicide Benomyl with 50mg/ml of
antibiotic streptomycin further enhanced the survival rate and percentage of clean
culture up to 80%-100%. Multiple shoot production was obtained from all species of
Acacia on Murashige and Skoog (MS) medium supplemented with 2.0 mg/l
benzyladenine (BA) plus 0.5 mg/l of NAA. It was also noted that greater shoot
production occurred with combination of plant growth regulators with additives. The
maximum shoot number and shoot length was produced in medium supplemented with
2.0 mgl-1 benzyladenine (BA) + 0.5 mgl-1 of NAA + activated charcoal (0.1% w/v)
combined with 100 mgl-1 AdSO4. It produced maximum number of 9.0 shoots per
explant with 3.51 cm in length. Shoots were then elongated and rooted in an optimized
condition and further acclimatized to nursery condition.Another study was initiated to evaluate and identify sequence markers which gave
phylogenetic information to be used to infer relationship within Acacias at a fine level.
Primer designed based on second intron of LEAFY gene of A.mangium amplified the
specific region with single band except for A. hybrid. The amplified regions were
sequenced to reveal the species relationship within selected Acacias. Result revealed
that non coding region of the second intron of LEAFY gene is more variable and can
be used as marker for phylogenetic studies at lower taxanomic levels
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
In vitro regeneration of Acacia crassicarpa A. Cunn Ex benth through organogenesis from juvenile sources
Full text linkMicropropagation through tissue culture technique offers an alternative to traditional vegetative propagation to mass propagate selected trees for large-scale forest plantation. Therefore, this study aimed to develop a protocol for the micropropagation of A. crassicarpa. Nodal stem segment and leaf obtained from 2 month-old aseptically germinated seedlings were used as explant in this study. Nodal stem segment was found to be the most appropriate explant for shoot formation when cultured on a MS medium supplemented with 6-benzylaminopurine (BAP). The highest mean number of shoots (5) and the longest mean shoot elongation (8 mm) occurred on a medium supplemented with 0.5 mg l-1 BAP. The longest mean shoot length (8 mm) and the highest mean number of explants per culture (7) were obtained on medium without any plant growth regulator. When cultured on a medium supplemented with 2,4-dichlorophenoxy acetic acid (2,4-D), nodal stem segment explant developed roots and callus (after 14 days). The highest mean number of roots (8.3 = 8) and the longest mean root length (12.0 = 12 mm) were obtained from the medium supplemented with 10.0 and 2.0 mg l-1 2,4-D, respectively. The highest mean number of roots (20.6 = 21) and the longest mean root length (10.4 = 10 mm) were obtained from the medium supplemented with 10.0 and 2.0 mgl-1 2,4-D, respectively, while the highest intensity of callus was produced on a medium supplemented with 8.0 and 10.0 mg l-1 2,4-D, and which was only able to produce root without any shoot formation. The calli produced were compact, watery and white in colour. Survival rate of plantlets was higher (100%) when transferred into the autoclaved mixture of soil, sand and peat (3:3:1) than those transplanted in an unautoclaved soil mixture (6.6%). Survival percentages of the plantlets in the culture room and greenhouse condition were 85 and 100%, respectively
Multiple shoot induction of selected genotypes of Eucalyptus camaldulensis Dehn
Full text linkThe increasing demand of Eucalyptus camaldulensis for its multipurpose values has called forth efforts to produce improved materials of this tree species. Here we study the effects of plant growth regulators (PGRs) on multiple shoot induction and develop a protocol for a workable micropropagation of improved selected genotype of E. camaldulensis Dehn. Shoot tips and nodal segments initiated from meristematic region were cultured on Murashige and Skoog (MS) basal medium containing six concentrations of cytokinin i.e. 1.0, 1.5, 2.0, 2.5, 3.0 and 3.5 mgL-1 of 6-Benzylaminopurine (BAP) plus 0.1 mgL-1 of auxin i.e. α-Naphthalene Acetic Acid (NAA) or Indole Butyric Acid (IBA). Maximum mean shoot length (8.11mm) and mean shoot number (5.01) were obtained from shoot tips after four weeks of culture compared to the mean shoot length (7.73 mm) and mean number of shoots (4.75) from nodal segments. The best growth in terms of mean shoot length (11.83 mm) and mean number of roots (9.10) was obtained with a combination of 3.0 mgL-1 of BAP and 0.1 mgL-1 of NAA. Protocol developed in this present study can assist in the large scale plantation of E.camaldulensis in future
In vitro regeneration of bamboo species
Full text linkThis review paper discussed about journals related to micropropagation of bamboo species. In recent years, the application of tissue culture technique like in vitro micropropagation has been used to meet the demands for bamboo products. In the past 30 years, protocols for micropropagation of various bamboo species have been established by researchers from all over the world. The controlling factors for cultures such as the explants, culture medium, carbon sources, combination and concentration of plant growth regulators and other additional additives are varied amongst. The controlling factors are crucial in developing successful regeneration protocols for various bamboo species. This paper is attempted to review and summarize the available and up to date information regarding in vitro micropropagation of bamboos
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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