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Effort to increase rubber plant production should be done, especially rejuvenation for old rubber plant which in turn require high numbers of seedling within short time period. One of the method to provide rubber plant seedlings within short time period is through grafting technique which combine plant having strong rootas base stem and high production plant as upper stem (entres). The objective of this research was to study response of entres age and clone to growth of rubber seedling (Hevea brasiliensis Muell, Arg.) produced from green and brown grafting. This study was conducted from February 2019 to Februari 2020. This study used Factorial Randomized Block Design with entres age as the first factor consisting of 3, 6, 9, 12 and 15 months as well as clone as the second factor consisting of PB 260 and BPM 24. Data was analyzed by using analysis of variance and followed bywith Honestly Significant Different (HSD) test and regression analysis. The study results showed that the best treatment was entres having 9 months of age as indicated by grafting success, the speed of stum out, stumlength, stumdry weight, root length androot dry weight which had the highest values than that of other treatments. Clone of PB 260 was the best entres that was very compatible with base stem of GT1 clone than that of BPM 24 clone because it gave the highest yield in term of all observed parametes. The interaction between 9 month entres age and PB 260 clone was the best treatment

A seringueira (Hevea brasiliensis) é a espécie mais explorada para obtenção de borracha natural a partir do seu látex. Esta matéria prima é amplamente utilizada na indústria da pneumática, materiais médicos e derivados da borracha. Sua importância se dá por produzir látex com qualidade e quantidade superior de polímeros de borracha ema relação as demais espécies, tornando a borracha natural um material estratégico no setor. Muitas variedades clonais comerciais têm sido desenvolvidas nos programas de melhoramento. A identificação morfológica é, muitas vezes, subjetiva e insuficiente para a diferenciação dos genótipos. Assim, há uma demanda por ferramentas de identificação de plantas. Marcadores moleculares tem sido usado em outras culturas com sucesso. Outro método que tem se mostrado assertivo na discriminação de espécies arbóreas da Amazônia foi a espectroscopia VIS-NIR. Com o objetivo de discriminar clones comerciais de seringueira, as duas técnicas foram utilizadas. Dez microssatélites foram testados e a combinação de dois locos (A2365 e A2368) foi eficiente para discriminar os clones com perfil alélico único. A espectroscopia VIS-NIR apresentou potencial de discriminação dos clones utilizando a faixa VIS em folhas jovens e a faixa NIR em folhas maduras com presença de doença. Conclui-se que ambas as técnicas foram capazes de diferenciar os clones possibilitando a certificação clonal. The rubber tree (Hevea brasiliensis) is the most exploited species for obtaining natural rubber from its latex. This raw material is widely used in the pneumatics, medical materials and rubber products industry. Its importance is given by producing latex with superior quality and quantity of rubber polymers in relation to other species, making natural rubber a strategic material in the sector. Many commercial clonal varieties have been developed in breeding programs. Morphological identification is often subjective and insufficient to differentiate genotypes. So, there is a demand for plant identification tools. Molecular markers have been used successfully in other cultures. Another method that has been shown to be assertive in the discrimination of tree species in the Amazon was the VIS-NIR spectroscopy. In order to discriminate commercial rubber clones, both techniques were used. Ten microsatellites were tested and the combination of two loci (A2365 and A2368) was efficient in discriminating clones with a single allelic profile. VIS-NIR spectroscopy showed potential for discrimination of clones using the VIS strip on young leaves and the NIR strip on mature leaves with the presence of disease. It is concluded that both techniques were able to differentiate the clones enabling clonal certification. Made available in DSpace on 2021-01-07T09:03:06Z (GMT). No. of bitstreams: 1 27090.pdf: 2254772 bytes, checksum: e2711e2139c0d486fbc54473521cf712 (MD5) Previous issue date: 2020 Dissertação (Mestrado em Ciências e Inovação Tecnológica) - Programa de Pós-graduação em Ciência, Inovação e Tecnologia para a Amazônia, Universidade Federal do Acre, Rio Branco. Orientador: Tatiana de Campos, Co-orientador: Clarice Maia Carvalho.

Rubber ( Hevea brasiliensis ) growing in Latin America is severely limited by South American Leaf Blight, a disease caused by the Ascomycete fungus Microcyclus ulei , recently renamed Pseudocercospora ulei . Sustainable ways of controlling it may be genetic, using resistant cultivars, or may consist in seeking so-called “escape zones”, where disease incidence is low thanks to climatic conditions unsuitable for the fungus. After identifying one such zone on the Pacific coast of Ecuador, between 2006 and 2014 we used an 8.2 ha trial to compare the agronomic performance of ten rubber clones originating from Asia and Africa. The study focused on tree growth, susceptibility to the disease and clone phenology. For most of the assessed clones, the results obtained over 8 months showed good adaptability and a good agronomic performance during the immature period, so that tapping could begin on the earliest trees at 6½ years. An examination of the monthly values for climatic factors such as rainfall, relative humidity, minimum temperature and dew point temperature, showed that conditions during the dry season, which lasted 5 months, were detrimental to P. ulei fungus development, even though the mean relative humidity of the driest months did not fall below 75%. In addition, between September and December, the minimum temperature remained above the dew point temperature, preventing dew formation on the leaf surface. These conditions enabled the trees to complete their natural refoliation without any risk of parasite pressure, and to conserve a foliar density over 90% up to natural defoliation the following year. The results obtained during the early growing phase, i.e. the immature phase, confirmed the suitability of this zone for rubber growing, especially for materials with a high yield potential, despite their known susceptibility to the disease. These escape zones consequently offer an undeniable alternative for developing rubber, due to a low phytosanitary risk arising from P. ulei .

South American leaf blight (SALB) is the worst impairment for rubber tree cultivation in the Amazon. Hevea brasiliensis clones produce high latex yields but most are SALB-susceptible (SS). So, resistance has been searched in related species. We selected defense related genes among those differentially expressed while contrasting SALB-resistant (SR) and susceptible clones from three Hevea species. SS clones over-expressed pathways responsive to salicylic (SA) and also jasmonic acid, thus entering a self-harmful cycle. SR clones displayed tightly coordinated SA-responsive and stress-control pathways. Polymorphism in the selected gene sequences supported SS × SR clone divergence. Made available in DSpace on 2020-05-28T04:43:25Z (GMT). No. of bitstreams: 1 Differential-expression-and-structural.pdf: 10306207 bytes, checksum: dbc6db81b21fc50c716e2e5cfc1ad556 (MD5) Previous issue date: 2020

The variability of natural rubber (NR) properties has been partly ascribed to the 3 to 5% non-isoprene components (lipids, proteins, carbohydrates and minerals) present in NR. Of all the factors that might be held responsible for this variability, clonal origin has appeared to be prominent. The sugars and polyols of latex from five Hevea brasiliensis clones (RRIM600, GT1, PB235, PB260 and PB217) were extracted with ethanol after specific NR sample pretreatment in a cyclohexane/ethanol solution. Latex carbohydrates were characterised by high performance anion-exchange chromatography equipped with a pulsed amperometric detector (HPAE-PAD). Total extractable carbohydrates, single sugars and polyols were analysed for each clone to evaluate how clonal origin affected the variability of latex carbohydrate compositions. Significant clonal differences were identified, both in the total sugar and polyol contents of the latex, and in the quantity of each element. The differences between the latex extracts of clones GT1, PB217, PB260, PB235 and RRIM600 did not come solely from the presence of major carbohydrates, such as quebrachitol or sucrose, but also effectively from minor carbohydrates, such as sorbitol or galactose. Some minor carbohydrates could even be used as biochemical clone indicators.

Oxidative stress occurring during in-vitro culture is detrimental for clonal propagation by somatic embryogenesis in particular in Hevea brasiliensis. In previous work, overexpression of the gene encoding the cytosolic reactive oxygen species detoxification enzyme HbCuZnSOD led to reduce somatic embryo regeneration in Hevea. In this study, the role of antioxidant was tested by overexpression of the E.coli GSH1 gene involved in glutathione biosynthesis in rubber embryogenic callus lines. Transgenic lines were successfully established and some plants were regenerated. Overexpression of EcGSH1 gene led to glutathione over-accumulation, and affected dramatically the somatic embryogenesis process and plant development. Upon a water deficit treatment, these plants displayed the greatest drop in photosynthetic nitrogen use efficiency, higher proline content, and higher glutathione reductase activity. Changes induced in transgenic lines overexpressing HbCuZnSOD and EcGSH1 were discussed as well as possible applications on plant material propagation, overcoming loss of natural rubber production through Tapping Panel Dryness, and tropical soil remediation.

The forest tree species Hevea brasiliensis is extensively planted in the humid tropics to meet the increasing demand for natural rubber. Huge quantities of planting stock are therefore needed. The seed option remains the easiest and cheapest way to establish plantations of rubber trees but those show a great variability for vigor and also for latex yield. The rationale of produ- cing clones for overcoming this variability was already obvious in the early 1910’s but due to the difficulties encountered at that time for rooting shoots, grafting was used as an alternative cloning method. The striking increase in yield noticed from the graft-derived clonal plantations warranted their large scale development. Eventually, the budded clones by virtue of their much higher and uniform produc- tivity supplanted the seedlings in most industrial plantations. However, grafting is also associated with drawbacks and for decades efforts aiming at mass producing selected rubber tree clones on their own roots by rooted cuttings have been pur- sued. However, this approach was pro- gressively abandoned due to disappoin- ting rooting results and, from the 70’s onwards, priority has been given to in vitro methods which were booming during this period. But despite 40 years of heavy investments, industrial H. brasiliensis clones could still not be mass micropro- pagated in vitro efficiently enough to meet the requirements of large scale produc- tion. The situation may change radically soon, however, due to the development of new nursery techniques adapted to the mass clonal production by rooted cuttings of any H. brasiliensis selected genotype. Efforts to improve the techniques as well as the establishment of new field trials are underway in order to determine if self-rooted rubber tree clones are more productive than grafted ones. This old issue is becoming of overriding impor- tance considering the increasing pres- sure on land availability reducing thereby the prospects for expanding rubber tree plantations.

As a highly conserved protein, the translationally controlled tumor protein (TCTP) carries out vital roles in various life processes. In rubber tree, two TCTP genes, HbTCTP and HbTCTP1, were cloned, but only HbTCTP1 was studied in details. In this study, cis-acting regulatory elements, expression patterns, subcellular localization, interacting proteins, and antioxidant activity of HbTCTP were systematically analyzed. Besides the common cis-acting regulatory elements, HbTCTP promoter also harbored various known cis-elements that respond to hormone/stresses. Being consistent with the aforementioned results, HbTCTP was regulated by drought, low temperature, high salt, ethylene (ET), wounding, H2O2, and methyl jasmonate (MeJA) treatments. HbTCTP was expressed throughout different tissues and developmental stages of leaves. In addition, HbTCTP was associated with tapping panel dryness (TPD). HbTCTP was localized in the membrane, cytoplasm and the nucleus, and interacted with four proteins rubber elongation factor (REF), 17.5 kDa heat shock family protein, annexin, and REF-like stress related protein 1. Being similar to HbTCTP1, HbTCTP also indicated antioxidant activity in metal-catalyzed oxidation (MCO) system. Our results are useful for further understanding the molecular characterization and expression profiles of HbTCTP, but also lay a solid foundation for elucidating the function of HbTCTP in rubber tree.

International audience; Selection for drought-tolerant clones has become a major challenge in rubber breeding programs undertaken to ensure the sustainability of natural rubber production, as rubber plantations are expanding in drought-prone areas. Xylem vulnerability to cavitation is a trait related to drought-induced mortality. It can be rapidly evaluated without subjecting plant materials to drought stress, making it useful in large-scale screening for drought tolerance in the near future. We first compared the most widely used techniques for measuring vulnerability to cavitation (air pressurization and Cavitron) on this species, and the effect of sample conditions (size, age and sunlight exposure), in order to ensure reliable analysis. Secondly, ten rubber clones were compared for their xylem vulnerability to cavitation in branches and petioles, and for other traits related to drought response, including stomatal response and leaf shedding occurring during a simulated drought. We also tested the plasticity of vulnerability to cavitation on two clones grown in three locations with contrasting precipitation regimes. We found no clonal variability and a small phenotypic plasticity for xylem vulnerability to cavitation in branches. However, clonal differences in xylem vulnerability to cavitation were found in petioles, and clones also showed differences in stomatal response and in leaf shedding behavior in response to a simulated drought. Our study suggests a genetic canalization for vulnerability to cavitation in organs critical for survival, such as branches, whereas there are clonal differences for traits related to drought avoidance: vulnerability to cavitation of petioles, leaf shedding behavior and stomatal response. The insights gained in this study for screening rubber tree clones for drought tolerance is also discussed.

Lipids of fresh latex from three Hevea brasiliensis clones (RRIM600, BPM24, and PB235), and of sheet rubber produced from it, were extracted by an optimized method and characterized through various chromatography techniques. Total and free fatty acids, phospholipids, glycolipids, and the unsaponifiable fraction were analyzed for each clone. Qualitative and quantitative comparisons of total extractable lipids indicated a smaller amount in sheet rubber (2.31-3.28%?w/w dry rubber) than in fresh latex (3.36-3.67%). Partial hydrolysis during primary rubber processing, such as polar lipids, was found to be the main source of this loss. Alongside the effect of primary processing, the clonal origin of the trees was found to be the main factor for differences in lipid quantity and composition. Practical applications: Lipids are the main non-isoprene components in natural rubber (NR) and play many important roles in NR properties. Detailed knowledge of the lipid composition would contribute towards a better understanding of the structural and physical properties of NR. The lipid composition also appears to be sufficiently specific to consider its use as a new tool for tracing the clonal origin of NR. (Resume d'auteur)

O percevejo-de-renda Leptopharsa heveae Drake & Poor (Hemiptera: Tingidae) é uma das mais importantes pragas da heveicultura no Brasil, principalmente nas regiões Sudeste e Centro-Oeste. Devido ao seu hábito sugador, na face abaxial das folhas, esta praga leva à senescência precoce das mesmas e a reduções na produção de látex em até 30%. Dentre os inimigos naturais de L. heveae está o parasitoide de ovos Erythmelus tingitiphagus (Soares) (Hymenoptera: Mymaridae), regulando suas populações em condições naturais. O objetivo deste estudo foi verificar a dinâmica populacional deste parasitoide, bem como correlacioná-la com os fatores meteorológicos temperatura e pluviosidade, em plantio comercial de seringueira do clone PB 217, em Itiquira, MT. Semanalmente foram coletadas quatro folhas maduras por árvore, no terço inferior da copa de 40 árvores, totalizando 160 folhas por amostragem, no período de agosto de 2006 a janeiro de 2007. Houve correlação positiva entre a dinâmica populacional e os fatores meteorológicos, sendo o pico populacional do parasitoide observado no mês de novembro e declinando até janeiro na área estudada.

De jeunes feuilles de différents clones d'Hevea sont infectées en conditions contrôlées par Microcyclus ulei. Six heures après l'inoculation, une fluorescence bleue intense sous UV est émise autour du point de pénétration. La rapidité d'apparition de cette fluorescence sur la majorité des points de pénétration est en relation avec le degré de résistance du clone : 12-36 h chez les clones à résistance totale, 36-120 h chez les clones à résistance partielle de bon niveau et 120 h après inoculation chez les clones à résistance partielle faible. La scopolétine est probablement le seul composé responsable de cette fluorescence. Une accumulation importante de cette coumarine, pourrait stopper l'invasion du pathogène au cours des premières phases de son développement. Quatre jours après l'inoculation, une accumulation intense de lignine concernant quelques cellules autour du site de pénétration, est observée chez les clones à résistance totale. Chez certains clones à résistance partielle, leur accumulation intense et étendue à une large zone autour de la lésion pourrait circonscrire le développement du pathogène

In Africa and particularly in Côte d'Ivoire, the exploitation of Hevea brasiliensis clones having strong vegetative growth based on the criterion of vigour adopted so far has raised physiological and physical problems characterized by a high rate of tapping panel dryness and wind damage. A study was conducted on three clones of Hevea brasiliensis (PB 235, GT 1 and PR 107) belonging respectively to classes of fast, moderate and slow vegetative growth, in order to determine the right moment for an exploitation which would minimize those drawbacks. Trunk measurements, bark collecting and histological sections followed by laticifers counting made on rubber trees aged from one to fifteen years, have enabled to describe the process of establishment of bark and laticifers. The intensity of development and thickening of the bark and the rate of laticifer emission are described respectively by distinct hyperbolic and logistic sigmoid functions. However, their temporal evolution is strongly marked by an irreversible decrease of the whole process of formation, whatever the clone, from six years after planting. Furthermore, the density of laticifers per mm2 switches, whatever the clone studied, from a number greater than 5, the first six years (5-8 < ?lv

Restriction fragment length polymorphism was assessed in wild and cultivated populations of Hevea brasiliensis using random probes from an Hevea nuclear library. One-hundred-and-sixty-four individuals were surveyed, and the results discussed in the light of previous work performed on isozyme variation. Both studies show that germplasm collections have led to an effective enrichment of the genetic resources available for Hevea breeding, and that cultivated clones have conserved a relatively high level of polymorphism, despite their narrow genetic base and their high level of inbreeding. An equivalent level of polymorphism is revealed by random nuclear probes and isozymes. However, the genetic structuring of the diversity appears more striking using RFLP markers. Wild accessions can be divided into three genetic groups according to their geographical origin. The present results are an essential guide to the incorporation of wild material in breeding schemes.

The rubber crops profitability depends largely on genotypes established in plantations, meaning that clone identity must be ascertained. This work was aimed at identifying commercial clones Hevea sp. by microsatellites. Primers were designed from sequences reported in Genbank using Primer3, PrimerQuest and OlgoPerfect software for PCR amplification of microsatellites. The primers so obtained were thermodynamically analysed by Oligo Analyzer 3.1 software and experimentally evaluated on 12 Hevea sp. clones. The 15 of the 561 microsatellite markers were selected; they had 2- and 3-bp repeat motifs and 11- to 23-bp repeat extension ranges. The most informative ones were microsatellites amplified with SSRH103, SSRH134, SSRH510 and SSRH516 primers with seven alleles and SSRH403 primers with eight alleles. Four microsatellite markers were sufficient for discriminating 10 of the 12 clones. Clustering analysis involved all the markers on the clones evaluated here, showing Brazilian clones' narrow genetic base compared to Asiatic ones. The current work provides new markers and joins work published by other authors for identifying and diversity studies of natural rubber clone La rentabilidad del cultivo de caucho depende en gran medida de los genotipos establecidos en plantación, por lo tanto es necesario asegurar la identidad de los clones. Este trabajo tuvo como objetivo identificar clones comerciales de Hevea sp. mediante microsatélites. Se diseñaron primers a partir de secuencias reportadas en el Genbank con los programas Primer3, PrimerQuestSM y OlgoPerfectSM para amplificación por PCR de microsatélites. Los primers obtenidos se analizaron termodinámicamente mediante el programa Oligo Analizer 3.1 y se evaluaron experimentalmente sobre 12 clones de Hevea sp. Se seleccionaron 15 de 561 marcadores microsatélites con motivos de repetición de 2 y 3 pb y rangos de extensión entre 11 y 23 repeticiones. Los más informativos fueron: con siete alelos los microsatélites amplificados con lo primers SSRH103, SSRH134, SSRH510 y SSRH516, con ocho alelos los primers SSRH403. Cuatro marcadores micrlites fueron suficientes para discriminar diez de los 12 clones. El análisis de agrupamiento realizado con la totalidad de los marcadores sobre los clones evaluados, evidencia la estrecha base genética de los clones brasileños respecto a los asiáticos. Este trabajo aporta nuevos marcadores y se suma a los publicados por otros autores, para la identificación y estudios de diversidad de clones de caucho natural

It is well known that the productivity and the susceptibility to the tapping panel dryness (TPD) of Hevea brasiliensis are determined by the intrinsic feature of each clone but also by the tapping system. Thus, in order to establish the tapping system that minimizes the TDP occurrence an experiment was carried out in Cote d'Ivoire with four high yielding clones including, PB 235, PB 255, IRCA 18 and IRCA 111. Five tapping systems (d2 6d/7 0/y, d3 6d/7 4/y, d4 6d/7 6/y, d5 6d/7 8/y, d6 6d/7 10/y) were applied to these clones, corresponding to a range of 100 % to 30 % of tapping intensities. The results show that the occurrence of TPD is closely related to the tapping intensity and the tapping system which consists in tapping twice per week with one day rest (S/2 d3 6d/7 4/y), was found to be the best tapping system. A quadratic relation was found between the rate of the TPD and the tapping intensity. Thus the clones IRCA 18 and IRCA 111, like PB 235 and PB 255, belong to the active metabolism clones. These clones also showed their adherence to the group of high rubber producer clones. This experiment also gave further evidence that the production of a tree for the tapping strongly depends on the intensity of tapping. It has also indicated that the intensity of tapping governed the tapping panel dryness rate among the clones having active metabolism, such as IRCA 18, IRCA 111, PB 235 and PB 255. (Resume d'auteur)

In order to update the clonal recommendations in Cambodia, a set of 14 Large Scale Clonal Trials (LSCT) was analysed globally for 36 clones, based on linear adjustments of the data from each trial. Although this method was statistically not very powerful, it made possible to compare all the clones between each other, whatever the trials in which they were set. Among the 36 clones, the adjusted mean girth at opening varied from 41 cm (RRIC102) to 52 cm (PB235), with a medium group of 20 clones (including GT1) varying from 46 cm to 48 cm. The cumulated yield over the first 7 years of tapping (Cum1?7) varied from 5279 kg/ha (K2) to 14935 kg/ha (IRCA130). The ranking of the clones by decreasing girth at opening was as following : PB235, PB330, IRCA130, IRCA209, PB280, IRCA111, KV4, IRCA230, TJIR1, PR261, IRCA209, PB310, PB254, GT1, AVROS208, PB255, PB260, RRIC121, IRCA18, RRIM600, RRIC101, RRIM712, PB314, PB217, KHA9, PR306, BPM24, PR303, PR255, K2, IRCA41, PR300, PR107, PB324, PB86, and RRIC102. The ranking of the clones by decreasing cumulated yield over 7 years of tapping (Cum1?7) was as following : IRCA130, PB235, KV4, RRIC101, IRCA109, PB314, RRIM712, PB280, PB260, IRCA230, RRIM600, PB330, PB310, PR303, IRCA111, RRIC121, PB255, IRCA41, PB254, PB217, PR300, PR255, BPM24, IRCA18, PR306, IRCA209, PB324, GT1, PB86, KHA9, PR261, PR107, RRIC102, AVROS308, TJIR1, and K2. The relationships between girth at opening and yields were examined, and a method was carried out for making cumulated yields independent from girth at opening (Cum1?7reg). However this correction had important effects only for the two extreme clones PB235 (highest vigour) and RRIC102 (lowest vigour). There was a good correlation between the initial yield of the first four years (Cum1?4) and the later yield from year 5 to year 7 (Cum5?7) with R² = 0.40. Girth at opening partly explained the initial yield (R² = 0.37), but its correlation with the later yield was non significant (R² = 0.09). Initial yield was generally higher than later yield for high?yielding clones, and the opposite was found for low?yielding clones. By decreasing order of Cum1?7, the clones with initial yield higher than later yield were IRCA130, PB235, RRIC101, PB314, PB280, PB260, IRCA230, IRCA111, PB255, IRCA18, and IRCA209 (group A, quick?starters). The clones with initial yield equivalent to later yield were KV4, IRCA109, RRIM712, RRIM600, PB330, PB310, IRCA41, PB254, PB217, PR300, PR255, BPM24, GT1, PB86, and PR261 (group B). The clones with later yield higher than initial yield were PR303, RRIC121, PR306, PB324, KHA9, PR107, RRIC102, AVROS308, TJIR1, and K2 (group C). These results were submitted to a critical discussion for application to clonal recommendations.

This specific reports aims at presenting DNA analysis for clonal identity checking, as well as proposals and the results of one series of 96 DNA analyses of samples collected from Cambodia during the mission (Crri, Chup, Krek, Royal Caoutchouc). These results are presented as an example of what could be carried out with Cirad for the certification of "reference budwood gardens" or for the publication of a list of budwood gardens from the private sector which successfully pass a quality test. Cirad proposes to address the checking of the 123 units of budwood gardens of the private sector (smallholders), of more than 0.20 ha, which make 90 % of the total. Based on 3 samples per unit, a total of 369 analyses should be carried out in priority. This would allow one to identify the budwood gardens of good quality (no mistake found among three samples), and would provide an accurate evaluation of the global budwood garden quality in the private sector. Further development should then be considered.

The influence of plant growth regulators, sucrose, calcium and various macronutrient media on callus friability and somatic embryogenesis was investigated inHevea brasiliensis Mull. Arg. Friable and embryogenic calli were spontaneously formed in two rubber tree clones (PR 107 and RRIM 600) on the Medium for Hevea (MH), with 3,4-dichlorophenoxyacetic acid (3,4-d), kinetin and sucrose, while compact embryogenic calli were enhanced in three other clones (PB 260, PB 235 and GT1). Callus friability was enhanced in clone PB 260 when the concentration of one growth factor (3,4-d or kinetin) was reduced from 4.5 μLM to 0.45 μM during the first culture, or when high sucrose or calcium levels 351 mM and 12 mM, respectively) were maintained during subcultures. The different macronutrient media did not alter callus texture but only use of MH and Murashige and Skoog (MS) media led to somatic embryogenesis. Friable calli obtained by modifying the auxin/cytokinin balance lost their embryogenic potential. In contrast, those obtained on media with high sucrose or calcium concentrations were mainly composed of embryogenic cells embedded in a mucilaginous matrix. Such calli could be of potential interest for establishing embryogenic cell suspension cultures.

International audience; Les recommandations et le choix final des clones d'hévéa pour la culture de nouvelles parcelles déterminent les conditions de valorisation du progrès génétique chez cette espèce pérenne cultivée pour la production de caoutchouc naturel. Une approche multicritère de sommes pondérées est classiquement utilisée pour classer les clones en fonction de leurs performances connues. La présente étude explore les possibilités de la méthode multicritère d'aide à la décision Électre III à partir d'une matrice d'évaluation des performances de 30 clones basée sur les résultats d'un réseau multilocal d'expérimentation situé en Côte d'Ivoire et dans d'autres pays africains. Cette méthode, qui utilise également une pondération des critères, offre différentes possibilités permettant de nuancer les résultats en prenant en compte une part d'incertitude sur les données. Elle se distingue également de la méthode des sommes pondérées par une approche consistant à comparer systématiquement tous les couples de clones possibles pour chaque critère. Elle permet d'expliciter le cadre servant à la prise de décision et d'organiser une discussion claire avec les décideurs pour aboutir à un cadre consensuel et discuter ensuite en confiance des résultats.

The influence of water deficit on self-rooting vitroplants of clone PB260 regenerated by somatic embryogenesis was investigated. Physiological responses including transpiration, stomatal conductance and fluorescence were monitored on leaves. Osmoprotectant compound like pro lin e, antioxidants and reactive-oxygen speciesscavenging enzymes like ascorbate peroxidase, glutathione reductase were analyzed during the stress. These responses are used io determine defence mechanism involved in drought tolerance and identifY parameters to be used as indicators in breeding programme or for genetic modification.

Transcript sequences were produced for the Hevea brasiliensis clone PB 260 by the pyrosequencing technique. Total mRNAs were isolated from different tissues col!ected from plants at different stages of development and having undergone different treatments in order to have the most complete representation of the expressed genome. A pipeline of bioinformatics analyses was developed to assemble the reads produced by the GS-FLX 454 (Roche Applied Science) in contigs. This database of transcript sequences for clone PB 260 is a source ofinformationfor molecular biologists and geneticists. The number of genes expressed in Hevea brasiliensis was also evaluated.

The inner integument from the young seeds of rubber tree clone Reyan88-13 was used to induce embryogenic callus. The different culture parameters such as the different types and concentrations of plant growth regulators and different calcium concentrations were studied in embryogenic callus induction media and subculture media. The proper culture parameters were determined. Friable and embryogenic callus were gradually obtained via continuous subculture and selection during 6 months. The suitable friable and embryogenic callus induction medium was: MH basal components, supplemented with 0.5 mg/L KT,2.0 mg/L 2,4-D, 11.0 mmol/L CaCl2, 80.0 g/L sucrose and 2.0 g/L Phytagel. Long-term subculture had been carried on for the friable and embryogenic calli. Histological sections proved that the calli proliferated by long -term subculture maintained the embryogenic characters. The friable and embryogenic calli of rubber tree clone Reyan88-13 that had been subcultured for more than 2 years were used for inducing somatic embryos. More than 16 000 somatic embryos were acquired, then 115 regeneration plantlets were obtained.

Resistance of rubber tree clones to South American Leaf Blight (SALB) caused by the fungus Microcyclus ulei is normally assessed in specific large-scale clone trials, which in general entail a considerable amount of work. Four variables are observed monthly on each tree over many years: disease severity and conidial sporulation intensity on young leaves, and severity and stroma density on mature leaves. In order to simplify this field assessment method, we tested the resistance of eight rubber tree clones to M. ulei in Ecuador in a Fisher block design with four replicates per treatment. Three months after planting, monthly observations were made for a period of 12 months on the foliage focusing on the four variables, in order to quantify disease development. Given the correlations between the four variables, assessment of conidial sporulation intensity on young leaves and stroma density on mature leaves should be sufficient. The most suitable period to start the assessment was 6 months after planting, for a duration of six to nine months. As repeated observations on the same trees were autocorrelated, it was possible to reduce the assessment frequency to once every 2 months. To conclude, assessing the resistance of rubber tree clones to SALB in large-scale clone trials can be optimized to reduce the number of observation times by 50%.

The nucellar tissue from the young seeds of rubber tree clone Reyan88-13 was used to induce embryogenic callus. The different culture parameters such as the different types and concentrations of plant growth regulators and different calcium concentrations had been studied in embryogenic caHus induction media and subculture media. The proper culture parameters had been determined. Via continuous subculture and selection during 5 months, friable and embryogenic callus had been gradually obtained. Long-term subculture had been carried on for the friable and embryogenic calli. Histological sections proved that the calli proliferated by long-term subculture maintained the embryogenic characters. The nucellar friable and embryogenic calli of rubber tree clone Reyan88-13 that had been subcultured for more than 2 years were used for inducing embryoids. At present 186 embryoids were obtained. These embryoids were being used to induce plant regeneration.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T19:01:48Z No. of bitstreams: 1 S0104-14282009000100015.pdf: 1609118 bytes, checksum: 77615d796420f66bf0dfdfde97e09c85 (MD5) Made available in DSpace on 2013-08-22T19:01:48Z (GMT). No. of bitstreams: 1 S0104-14282009000100015.pdf: 1609118 bytes, checksum: 77615d796420f66bf0dfdfde97e09c85 (MD5) Previous issue date: 2009-01-01 Made available in DSpace on 2013-09-30T20:02:10Z (GMT). No. of bitstreams: 2 S0104-14282009000100015.pdf: 1609118 bytes, checksum: 77615d796420f66bf0dfdfde97e09c85 (MD5) S0104-14282009000100015.pdf.txt: 39558 bytes, checksum: b5953e5298a5fcae15b4a251b741c826 (MD5) Previous issue date: 2009-01-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:22:57Z No. of bitstreams: 2 S0104-14282009000100015.pdf: 1609118 bytes, checksum: 77615d796420f66bf0dfdfde97e09c85 (MD5) S0104-14282009000100015.pdf.txt: 39558 bytes, checksum: b5953e5298a5fcae15b4a251b741c826 (MD5) Made available in DSpace on 2014-05-20T13:22:57Z (GMT). No. of bitstreams: 2 S0104-14282009000100015.pdf: 1609118 bytes, checksum: 77615d796420f66bf0dfdfde97e09c85 (MD5) S0104-14282009000100015.pdf.txt: 39558 bytes, checksum: b5953e5298a5fcae15b4a251b741c826 (MD5) Previous issue date: 2009-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Neste trabalho estudou-se o desempenho mecânico e térmico de compostos de borracha natural (Hevea brasiliensis) de 4 diferentes clones (GT 1, IAN 873, PB 235 e RRIM 600) cultivados no Estado de São Paulo, assim como de uma mistura destes clones e de uma borracha comercial, GEB-1. Estas borrachas foram formuladas e vulcanizadas com tempos de 5, 7 e 9 minutos. A caracterização foi realizada por calorimetria exploratória diferencial, termogravimetria, ensaios de resistência à tração, análise dinâmico-mecânica, medidas de dureza Shore A, microscopia eletrônica de varredura e espectroscopia na região do infravermelho. Os resultados permitiram concluir que o tempo de vulcanização e o tipo de clone não influenciaram na temperatura de transição vítrea (Tg) dos compostos. Os valores de Tg obtidos por DMA foram de cerca de -62 °C, e os resultados ensaios de dureza apresentaram valores próximos de 60 para todos os compostos estudados. Os ensaios de resistência à tração mostraram que o melhor desempenho mecânico foi obtido pelo clone RRIM 600. de acordo com os resultados obtidos neste trabalho, todos os clones atingiram as propriedades reportadas na literatura, podendo ser utilizados, em princípio, nas indústrias de artefatos de borracha separadamente ou na forma de mistura. The objective of this work was to study the mechanical and thermal performance of natural rubber (Hevea brasiliensis) compounds of different types of clones (GT 1, IAN 873, PB 235 and RRIM 600), as well as a mixture made from these clones and a commercial rubber GEB-1. These rubbers were formulated and prepared in a two-roll mill and vulcanized at different times (5, 7 and 9 minutes). The evaluation of the mechanical and thermal performance of different natural rubber compounds was carried out by differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), mechanical properties (tensile and hardness tests), dynamic mechanic thermal analysis (DMTA), scanning electron microscopy (SEM), and infrared spectroscopy (FTIR). The values obtained for glass transition temperature (Tg) for vulcanized rubbers were found to be around -62 °C, while in the hardness test the values obtained were close to 60, with no great variations when the vulcanization time and type of clone were varied. The tensile tests showed that the best performance was obtained for the clone RRIM 600. All the samples studied were in agreement with standard specifications required for application in the rubber industry, indicating that all clones can be used, in principle, in the rubber industry in blended or unblended forms. USP Interunidades em Ciência e Engenharia de Materiais Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) Instrumentação Agropecuária Apta/IAC Instituto Agronômico Programa Seringueira UNESP Departamento de Física, Química e Biologia UNESP Departamento de Física, Química e Biologia

Esta misión respondía al cuadro del convenio de cooperación técnico y científico entre el Cirad y el Gremial de Huleros, como apoyo al funcionamiento del departamento de investigación sobre el caucho en Guatemala. Se ha centrado en el estudio de las producciones de las fincas visitadas, la estimación del estatus fisiológico de los árboles de las parcelas piloto del año 2008 y la recomendación de los sistemas de pica más adaptados a los clones en producción. Al mismo tiempo, se ha podido garantizar la formación de investigadores del CEG encargados de las pruebas agronómicas y del seguimiento de las parcelas de hevea en las fincas. El estudio de las fincas y de los resultados obtenidos nos demuestra que la explotación de las parcelas de hevea es, en general, óptima. Las recomendaciones del experto del Cirad se han limitado a la disposición de los paneles y a los sistemas de pica y estímulo. Hay que trabajar de nuevo los datos adquiridos en ficheros que deben reintroducirse siguiendo el modelo del Cirad. La recogida del conjunto de informaciones procedentes de las parcelas llamadas "elementales" alimentará una base de datos para Guatemala. Se ha actualizado nuevamente la base de datos del DL. Durante la misión, ha tenido lugar una formación que perseguía validar con los sangradores del Gremial las recomendaciones de explotación de las unidades de cultivo afectadas. El Gremial de Huleros ha mostrado su interés por probar en Guatemala clones de alta producción y resistentes al SALB con el fm de considerar su potencial de producción tanto en zona sana, como en zona "microcyclus". El experto del Cirad animó la conferencia del Gremial de Huleros en Ciudad de Guatemala el 17 de noviembre de 2008.

Clone IRCA 11 1 was developed in Côte d'Ivoire in 1975 to contribute in increasing the rubber production. Nine years of study were conducted on a large scale to identrfy the optimal tapping system for its exploitation before being released to the producers. The experimental design was that of a Randomised Complete Bloc (RCB). Among the six tapping systems tested (% S d/2 6d/7; % S d/3 6d/7. ET 2.5%. Pa 1 (1). 4/y; % S d/4 6d/7. ET 2.5%. Pa 1 (1). 44; % S d/4 6d/7. ET2.5%. Pa 1 (1). 8/y; % S d/5 6d/7. ET 2.5%. Pa 1 (1). 8/y and % S d/6 6d/7. ET2.5%. Pa 1 (1). 10/y) tapping twice per week with 4 annual stimulations (% S d/3 6d/7. ET2.5%. Pa 1 (1). 4/y) turned out to be the optimal exploitation system for IRCA 11 1. Nevertheless, with a Iimited number of tappers, weekly tapping with 10 annual stimulations (% S d/6 6d/7. ET 2.5 %. Pa 1 (1). 10/y) was the most appropriate. The production of rubber per tree andper tapping (g/t//t) was in logarithmic relation with the intensiw of tapping. The rate of tapping panel dvness (TPD) was related to the intensiw of tapping by a quadratic polynomial function. The study also demonstrated that IRCA 111 had a high yield, a fast growth rate and an active metabolism as compared to the standard clone PB 235.

CONTENIDO Editorial.La educación agroforestal en la facultad de ciencias forestales y ambientales.Agroforestry education at the forestry and environmental sciences faculty. Petit Aldana, Judith Artículo Mejoramiento en la eficiencia de fertilizantes químicos con biofertilizantes para producir maíz en suelo Alfisol (Chac-lu’um). Chemical fertilizer efficiency improvement with biofertilizer to produce maize in Alfisol soil (Chac-lu’um). Uribe V., Gabriel; Petit, Judith y Roberto, Dzib E. Relaciones fenéticas en especies de Sterculia L. (Sterculiaceae) en Venezuela. Sterculia L. species (Sterculiaceae) phenetic relationships in Venezuela. Mondragón, Alcides; Máyida, Elsouki y Castillo, Aníbal Principales causas de la deforestación en la vertiente sur del Parque Nacional Sierra Nevada, Venezuela. Deforestation main causes in the south slope of Sierra Nevada National Park, Venezuela. Gómez T., Hugo A. y Molina, Misael Dinámica sucesional del componente arbóreo, luego de un estudio destructivo de biomasa, en el bosque universitario San Eusebio, Mérida-Venezuela. Arboreal component sucesional dynamics, after a destructive study of biomass, in San Eusebio university forest, Mérida, Venezuela. Ramos, María Cristina y Plonczak Ratschiller, Miguel Andrés Establecimiento de lianas sobre los árboles de un bosque del chaco húmedo argentino. Tree liana establishment of a forest from the argentinean humid chaco. Lorea, Luciano y Brassiolo, Miguel Periodicidad de los anillos de crecimiento en Pinus caribaea var. hondurensis proveniente de una plantación delestado Mérida, Venezuela. Growth ring periodicity in Pinus caribaea var. hondurensis from a Mérida State plantation, Venezuela. Melandri, José Luis; Dezzeo, Nelda y Espinoza de Pernía, Narcisana Planificación de la explotación de impacto reducido como base para un manejo forestal sustentable en un sector de la Guayana venezolana. Reduced impact exploitation planning as a base for a sustainable forest management in an area of the Venezuelan Guyana. Noguera L., Oscar E.; Pacheco A., Carlos E.; Plonczak Ratschiller, Miguel Andrés; Jeréz R., Mauricio; Moret, Ana Yajaira; Quevedo R., Ana Mercedes y Carrero G., Omar E. Potencial papelero de clones de Hevea brasiliensis procedentes del estado Amazonas, Venezuela. Paper potential of Hevea brasiliensis clones from Amazonas State, Venezuela. Zerpa, Juan; Mogollón, Gladys M.; Gutiérrez G., Ilvania y Aguilera, Antonio V. Ecuaciones de volumen para árboles de Samán (Samanea saman (Jacq.) Merr.), provenientes de potreros en el municipio Machiques de Perijá, Estado Zulia, Venezuela. Volume equations for Saman (Samanea saman (Jacq.) Merr.) trees growing in pasture lands of Zulia state, Venezuela. Moret, Ana Yajaira; Ortiz, Alba Guadalupe; Pérez, Yorfreddy; Quijada, Marcelino y Jeréz R., Mauricio Variabilidad de los vasos en Gmelina arborea Roxb. (Verbenaceae) proveniente de plantaciones del estado Portuguesa (Venezuela). Variability in vessels of Gmelina arborea Roxb. (Verbenaceae) from plantations in Portuguesa State (Venezuela). León Hernández, Williams J. y Quintero M., Maria Alejandra 79-86 gladysmb@ula.ve ilgutie@ula.ve antonioa@ula.ve semestral Nivel analítico

Afin d'augmenter la production de latex chez Hevea brasiliensis, l'éthéphon, un générateur d'éthylène, est aujourd'hui utilisé à l'échelle industrielle comme agent stimulant. Ce traitement a pour effet d'augmenter la durée d'écoulement du latex et d'améliorer sa régénération. L'éthylène semble donc coordonner un ensemble de voies métaboliques étudiées par une approche transcriptomique. Dans de précédentes études, des banques SSH (Hybridation suppressive et soustractive) ont donc été réalisées afin d'isoler les gènes de réponse à l'éthylène. Puis l'expression de ces gènes a été analysée par Reverse Northern sous l'impact de différents stress abiotiques (éthylène et blessure) chez trois clones à métabolisme contrasté (PB217, RRIM600 et PB260). La présente étude peut se diviser en deux parties. Dans un premier temps, l'objectif est de valider par RT-PCR quantitative l'expression de 3 gènes mis en évidence par Reverse Northern comme discriminant les trois clones à métabolisme contrasté. Les 3 gènes choisis sont HbPIP-like, HbHSP70 et HbACSF2. Dans un deuxième temps, il s'agit d'étudier l'expression, toujours par RT-PCR quantitative, de 4 facteurs de transcription susceptibles de jouer un rôle dans la régulation de gènes de réponse à l'éthylène. Ces facteurs de transcription avaient été mis en évidence dans les banques SSH. L'expression de chaque gène a été étudiée en cinétique chez de jeunes plants greffés des clones PB217, RRIM600 et PB260, en réponse à la blessure et à l'éthylène. Les résultats montrent que les gènes HbPIP-like et HSP70 pourraient permettre de discriminer les trois clones sous certaines conditions de stress. Les facteurs de transcription étudiés présentent également des variations significatives de leur expression sous l'impact des différents traitements.

Ethephon, an ethylene generator, stimulates both latex flow and regeneration. Given ethylene triggers the expression of numerous genes in latex cells, a transcriptomics approach was taken in order to understand the molecular mechanisms underlying latex production controlled by this hormone. Two cDNA libraries were constructed using Suppression Subtractive Hybridization (SSH) technology from 4-year-old trees of clone PB 260 in their immature period without stimulation or stimulated with 2.5% ethephon stimulated. Among 1158 sequenced clones, 158 unique transcripts were identified. Putative functions were assigned by sequence analysis using BLASTX, which showed a large number of genes related to transcription and protein synthesis, unknown functions or defence proteins. A high density filter was completed with genes involved in latex metabolism such as rubber biosynthesis and ROS-scavenging protein. Macro-array analysis revealed a general differential expression between clones with a contrasting metabolism. A large proportion of genes was up-regulated for the active metabolic clone PB 260, and by contrast, a down-regulation was observed for lower metabolisms such as PB 217 or RRIM 600. Discrimination of the response to ethylene for these clones was significant for 35 genes, and 5 of them might discriminate between the responses of the 3 clones. The differential gene expression by Real Time PCR upon ethylene stimulation was confirmed for some of these candidate genes. These genes could be used as markers of expression under stress in a marker-assisted selection programme.

La maladie sud-américaine des feuilles de l'hévéa (Microcyclus ulei, Ascomycètes), est la plus grave des maladies de l'hévéa. Elle est un obstacle à sa culture à très grande échelle en Amérique latine et constitue une menace sérieuse pour la filière caoutchouc naturel en cas d'introduction en Asie et en Afrique. La lutte s'est orientée définitivement, depuis plus de vingt ans, vers la sélection de clones d'hévéas résistants et vers la culture de l'hévéa dans des zones où les dégâts sont tolérables pour une hévéaculture rentable, mais les études sur l'épidémiologie de la maladie sont peu nombreuses. Ce travail aborde la maladie aux échelles de la feuille et du rameau en conditions naturelles, sur trois clones de sensibilités diverses. Elle montre qu'à de telles échelles, l'incidence clonale sur la dynamique de la maladie est détectable mais minime. L'effet de la phénologie, en relation avec le facteur clonai, ne s'exerce, en revanche, qu'à des échelles supérieures. Le climat, en région équatoriale, n'est quasiment jamais limitant, les infections étant possibles toute l'année. Son influence s'exerce surtout par l'intermédiaire des pluies, qui déclenchent la libération des ascospores et stimulent la production de jeunes feuilles sensibles. Mes résultats indiquent que les ascospores sont à l'origine de la dispersion de la maladie à longue distance et de son apparition dans des zones saines. Les conidies assurent la multiplication du champignon et la propagation de la maladie à courte distance en période de végétation des hévéas. Les infections sont favorisées par l'humectation des feuilles, qui n'est toutefois jamais limitante dans le contexte de l'étude. L'effet du climat est plus perceptible sur les clones sensibles que sur le clone résistant. La disponibilité en inoculum et la réceptivité de l'hôte apparaissent essentiels pour l'installation de la maladie, dont la propagation se révèle assez lente, conditionnée essentiellement par la présence de feuillage réceptif.

La presente misión se enmarca dentro del convenio de cooperación técnica y científica entre el Cirad y la Gremial de Huleros, para apoyar el funcionamiento del departamento de investigación sobre el hule en Guatemala. Básicamente, consistía en revisar el experimento agronómico conducido por la Gremial de Huleros y la capacitación de investigadores del CEG, encargados de los experimentos agronómicos y del seguimiento de las parcelas de hule en las fincas. De la revisión de los protocolos experimentales y de los resultados obtenidos se destaca la necesidad de estudiar nuevamente los datos ingresados en los archivos, los cuales es preciso adquirir según el modelo del Cirad. La recolección del conjunto de las informaciones procedentes de las parcelas llamadas "elementales" alimentará una base de datos para Guatemala. La base de datos del DL ha sido reactualizada. Se implementó un protocolo de actualización periódica en el CEG. Se prestó una colaboración para la interpretación de los datos de los DL comerciales, con el fin de validar las recomendaciones de explotación de las unidades culturales involucradas. Se discutieron nuevos protocolos con los ingenieros investigadores especialmente sobre: - los campos clonales a gran escala, las pruebas de explotación; frecuencia de pica y estimulación gaseosa. La Gremial de Huleros se mostró interesada en probar en Guatemala clones de gran productividad y tolerantes al SALB con el fin de calcular su potencial de producción en zona sana, al igual que en zona " microcyclus ". El perito del Cirad participó al taller hule de Mazatenango del 25 de mayo y a la conferencia de la Gremial de Huleros en Guatemala City del 28 de mayo 2007.