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HISTORY OF RUBBER AGROFORESTRY SYSTEMS DEVELOPMENT IN INDONESIA AND THAILAND AS ALTERNATIVES FOR SUSTAINABLE AGRICULTURE AND INCOME STABILITY
No full textPromoting environmentally friendly and socially responsible rubber cultivation is relatively new in current agricultural policies in Asia (since the 2010’s). However, agroforestry systems based on rubber are very old, based on local know-how. Their interest and recognition is relatively recent since the beginning of the 2000’s. If rubber was introduced in South Asia as a colonial crop, it would have been immediately adopted by local farmers since 1910’s and developed as a very extensive agroforestry system based on unselected rubber seedlings: the jungle rubber, established in Indonesia, Malaysia (North-Borneo) and southern Thailand. Malaysia in the 1950’s and Thailand in the 1960’s developed specific institutions and policies to replace jungle rubber by clonal monoculture and rapidly implemented highly productive new plantations based on clones. Indonesia started rubber clone development programs in the 1970’s. Though there is no more jungle rubber in Thailand and Malaysia (except a little bit in Sabah/Sarawak), there still exists between 2 and 2.5 million hectares of jungle rubber in Indonesia. Meanwhile, local famers started experimenting agroforestry practices themselves in the 1990’s, with clonal rubber, with fruits trees, wood/timber trees and other plants for additional source of income. Such systems have been reported in the 1990’s in Southern Thailand, West-Kalimantan and south/central Sumatra The rubber price volatility and its vulnerability to global market fluctuations in the last 30 years (from 0.5 to 5 US $ /kg) have compelled many farmers to leave the cultivation. Strategies for income diversification became priority. In a context of land scarcity, agroforestry appeared as the best-bet alternative to combine production and environmental and social issues. Local extension and research institutions have realized that agroforestry is a viable practice to overcome monoculture constraints (relying on one source of income only, rubber prices volatility etc) and provide environmental services. This new opening of local institutions to alternative agroforestry systems lead to more recognition and now promotion of environmental friendly and socially responsible rubber cultivation. Meanwhile, studies in the 2000’s in Indonesia and recently in Thailand in 2015/2016 show that agroforestry systems do limit various types of risks under different socio-economic conditions (erosion, price volatility etc.). The focus of the communication is put on rubber agroforestry systems history, advantages and recent findings in Thailand to overcome rubber price un-stability and maintain farmers’ income and resilience through diversification (fruits, legumes and timber) where innovation platform could be developed on existing knowledge and know-how. Keywords:  rubber agroforestry, Indonesia, Thailand, resilience, price volatility, sustainability, smallholder
FUNCTIONAL ANALYSIS OF HBMLO12 POWDERY MILDEW INFECTION AND STRESS RESPONSE IN RUBBER TREE HEVEA BRASILIENSIS MUELL ARG.
No full textPowdery mildew locus O (Mlo) gene was first found in barley as a specific powdery mildew resistance gene family. In order to classify the functions of mlo gene in disease resistance and stress response process in rubber tree, a mlo gene, namely Hbmlo12 was cloned from leaves of rubber tree clone CATAS7-33-97. Results showed that the ORF of HbMlo12 was 1721 bp in length, encoding a putative protein of 574 amino acids. HbMlo12 was a typical Mlo protein with eight-transmembrane domain. Sequence comparison between HbMlo12 and other Mlo proteins demonstrated that HbMlo12 shared the highest similarity with the Ricinus communis RcMLO-L12 and Arabidopsis thaliana AtMlo12 with 77% and 64% sequence identity, respectively. Phylogenetic analysis revealed that HbMlo12, RcMlo12-R, RcMlo-L3, AtMlo3, AtMlo12, AtMlo6, and AtMlo2 were grouped into cladeV with 100% bootstrap support value. HbMlo12 expression was tissue specific, and it was preferentially expressed in leaf. HbMlo12 expression significantly changed during powdery mildew infection at the Primary disease. Furthermore, the expression of HbMlo12 was significantly induced by various phytohormones (including ethephon, methyl jasmonate, salicylic acid, abscisic acid, and gibberellic acid). Under drought, wounding stress and indole-3-acetic acid and H2O2 treatment, HbMlo12 expression did not significantly change, but exhibited a complex pattern of regulation. This work provide a theoretical of that HbMlo12 might play a role in phytohormone signaling and abiotic stress response processes in rubber tree.Keywords: Hevea brasiliensis Muell Arg.; HbMlo12; powdery mildew; stress; phytohormone, rubber, disease resistance, gene, expression, phylogenetic analysi
EVALUATION OF PHYLLOPLANE , CAULOPLANE AND RHIZOSPHERE BACTERIA FOR MULTIPLE ANTAGONISM AGAINST FIVE MAJOR PATHOGENS OF RUBBER (HEVEA BRASILIENSIS)
No full textBacteria associated with phylloplane, cauloplane and rhizosphere of rubber (Hevea brasiliensis, clones RRII 105and PB 260) from six rubber growing regions in south-western India were isolated during monsoon, post-monsoon and summer seasons. These isolates were evaluated for antagonism against five major pathogens of rubber viz. Corynespora cassiicola, Colletotrichum acutatum, Phytophthora meadii, Corticium salmonicolor and Phellinus noxius. Out of the 118 isolates screened, 11  showed antagonism against all the five and 18 against a minimum of four of the pathogens tested. Among these, three phylloplane isolates (B24, B54 and B61) showed high inhibition of at least three pathogens. The mechanism of antagonism included production of volatile compounds, HCN and siderophores. In vivo evaluation of the three selected isolates for protection against leaf diseases caused by C. cassiicola and    C. acutatum on young rubber plants (clone RRII 105) grown in polybags confirmed their efficacy. Prior inoculation of the antagonistic bacterial isolates was more effective in reducing disease intensity
TRACKING CARBON FROM PHOTOSYNTHESIS TO LATEX WITH 13C FIELD LABELLING EXPERIMENT
No full textRubber trees must mobilize a huge amount of carbon to regenerate the latex after tapping. Knowing the C sources and pathways towards latex will help managing tapping systems. We labelled 4y-old tapped rubber trees with 13CO2 and analyzed 13C content in leaves, phloem, wood and latex during one year to determine the dynamics of C allocation. The peak of 13C in latex 10-15 days after labelling in June indicated that newly assimilated C was mixed in a pool of reserves before being used to regenerate latex. The earlier (6-8 days) and much higher peak in October showed that when the regeneration metabolism was well established the transfer of recent assimilates was faster. In both cases 13C was recovered more than 40 days after labelling, demonstrating the contribution of reserves. 13C recovery in soluble sugars and quebrachitol, an important osmoticum, are followed-up to specify their dynamics.Keywords: carbon allocation, carbohydrates, latex regeneration, reserves, stable isotopes
FRACTIONATION OF HEVEA BRASILIENSIS LATEX BY CENTRIFUGATION: (ii) A MEAN TO LOCATE THE DRIVERS OF NATURAL RUBBER UNIQUE STRUCTURE AND PROPERTIES
No full textThe biochemical composition of Fresh Hevea latex fractions (cream, skim, C-serum, lutoids) was comprehensively described in the first part of this publication. The fractions obtained from the same latex were remixed. The rebuilt latex was used to prepare ADS (Air Dried Sheet) rubber sheets.  The possible quantitative effects of the components of each fraction on the structure and properties of the obtained rubber ADS samples were studied. This protocol was performed on lattices harvested from 2 clones (RRIM600 and PB235). The obtained rubber samples made from latex containing various proportions of serum and/or lutoid fractions, were submitted to a panel of analytical characterizations: lipid extract, mineral composition, mesostructure (SEC-MALS), Initial Plasticity (Po), Plasticity Retention Index (PRI), and Accelerated Storage Hardening Test (ASHT). Moreover, non-accelerated 2- month storage in controlled conditions was also studied. While the proportion of serum and/or lutoid did not influence much the structure and properties of freshly obtained dry ADS rubber, an important effect of their presence was evidenced on the change of structure and properties during storage. For example, ADS rubber samples made from lutoid- and serum-deprived latex were those that showed the lowest DP (ASHT) and the lowest Dgel and DPo after 2-month storage. In addition, clonal differences in terms of lipid extract, rubber structure and properties were underlined : when compared to RRIM600 rubber, PB235 rubber showed higher lipid content, Po, Mn, Mw and  lower mineral content, DP (ASHT) and DPo(2-month non accelerated storage).Keywords: Hevea brasiliensis, latex fractionation, storage hardening
THE HEVEA LATEX DIAGNOSIS AS A CROP HARVEST MANAGEMENT TECHNIQUE: CONSEQUENCES OF STUDY AND IMPLEMENTATIONS ON PB 260 IN SOUTH EAST OF VIETNAM
No full textLatex Diagnosis (LD) is a physiological analysis of the condition of the laticiferous system in the area of the Hevea trunk that has been tapped (Jacob et al., 1989). Latex diagnosis is based on four biochemical parameters in latex namely sucrose, thiols, inorganic phosphorus and total solid content which are in mechanisms linked to yield. In other words, they were involved in flow and latex regeneration. The analysis could provide useful information on the state of health of the laticiferous system and the rubber production capacity of tapped trees at a given time (Eschbach et al., 1983). Since 1990, latex diagnosis has been studied and large - scale applied in some estates in Viet Nam. The technique is used to offer guidelines of annual stimulation scheme and prediction of the harvesting status of estates’ plantations for detecting over exploitation. PB 260 is a high yielder and one of the most popular clones by which 50% of the total cultivated areas of Viet Nam Rubber Group occupied. A study was undertaken in clone PB 260 over nine consecutive tapping years on panel BO-1 and BO-2 to evaluate evolution of latex physiological parameters, productivity and TPD under different intensities of tapping systems. In this study, trees were tapped under d3 and d4 frequencies and separated into four treatments per each tapping frequency: a control without ethepon stimulant and three groups were treated at 4, 6 and 8 stimulation rounds per year, respectively. In stimulated treatments, up to 15% - 20% of yield loss due to TPD in the BO-2 compared to in the BO-1 panel. The percentage of TPD in the BO-2 panel was twice as high as those in the BO-1 panel. The behaviors of these latex diagnostic parameters had significant differences between the different intensities of stimulation and tapping frequencies in the BO-2 panel. Whatever the tapping frequency is, increase in stimulation intensity led to decrease in the values of these parameters. Furthermore, there was no significant difference in values of LD elements between d3 and d4 tapping frequencies. Besides that, threshold values for LD parameters of clone PB 260 were developed under both S/2 d3 and S/2 d4 tapping systems. Sampling was carried out in 48 plots from three different estates in South East of Viet Nam including Dong Nai (16 plots), Phu Rieng (16 plots) and Dong Phu (20 plots) during a longterm period from 2009 to 2016. LD studies and setting up the standard base values of LD parameters for clone PB 260 were aimed to improve a unique crop harvest management technique for optimizing the yield in different growing regions and avoiding laticiferous system fatigue due to over-stimulation. Keywords: rubber, latex, yield, latex diagnosis, TPD, ethepon, stimulation, tapping frequen
ABSENCE OF TAPPING PANEL DRYNESS IN MEXICO HAS TO BE INVESTIGATED UPON
No full textIt is still disputed as to whether Tapping Panel Dryness (TPD) of Hevea brasiliensis is a physiological syndrome caused by abiotic factors or a disease caused by pathogen. Exact causative factor is still unknown. Majority opinion is that TPD is caused by some abiotic factors. It was also believed that TPD occurs in all countries where rubber is cultivated. However, in 2013 it was reported that TPD does not occur in the rubber plantations in Mexico. The popular clones of rubber trees cultivated in Mexico are IAN 710 and IAN 873. Clones RRIM 600 and PB 260 are also cultivated in a very small area. So far no one has contested this observation published in 2013. Since TPD is a major problem in rubber plantations in Asia and Africa, further investigations have to be conducted to confirm the observation and find out the possible reasons for the absence of TPD in Mexico. Data from past clone trials in Asia consisting of clones IAN 710 and IAN 873, if available may be re-examined for incidence of TPD. If not, new trials may be taken up on these clones for testing in Asia. If TPD occurs, other reasons can be ascribed for the reported absence of TPD in Mexico.Â
APPLICATION OF ARTIFICIAL INTELLIGENCE AND DRONE TECHNOLOGY IN MALAYSIAN PLANTATION
No full textDrone is fast becoming a crucial tool that enables precision in agriculture. The extra precision benefits farmers by allowing them to either save cost, increase yield, or speed up productivity. This paper will talk about applications of drone technology to enable precision farming for local crops: Rubber, oil palm & paddy. Some of the applications are palm tree counting, variable nutrient applicator sprayer drone, drone-aided precise terrace planning, and NDVI plant health indexing
PRODUCTION OF PB 260 RUBBER CLONE IN RELATION WITH FIELD WATER BALANCE
No full textIn general, rubber production is influenced by fluctuation of monthly rainfall rate. This research was aimed to determine the effect of rainfall, evapotranspiration and soil water content on the production of PB260 rubber clone. This research was conducted at Sembawa Research Centre Experimental Field, South Sumatra from year 2011 to year 2016. The observed rubber tree was mature PB 260 clone planted on clay loam soil. Rubber productions on dry and rainy season from2011 to 2016 were compared to determine the effect of rainfall, soil water content, and evapotranspiration on rubber production. Data were analyzed using SAS v.9 to determine the correlation value of each climatological parameters to rubber production from 2011 to 2016. The results showed that soil water content has the closest relationship with rubber production compared to the rainfall parameter. Latex yield was decreasing as the decrease of soil water content at dry season. Limited water on dry season was become a constraint of the optimum rubber yield.Keywords: PB 260 clone, Rubber production, water balance, rainfall, hevea, soil water content, evapotranspiration, latex, dry seaso
INFLUENCE OF STORAGE TEMPERATURE AND TIME ON MOONEY VISCOSITY AND BOUND RUBBER FORMATION IN NATURAL RUBBER COMPOUNDS FILLED WITH CARBON BLACK AND LOCAL SILICA
No full textAging experiments were carried out on natural rubber compound filled with both carbon black and silica.  The type of silica employed in this research was local silica. Silica loading was 0, 5, 10, 15 and 20 phr, and carbon black was set to be fixed. The samples were subjected to thermooxidative aging at temperatures mainly at 40 oC, 45 oC, 50oC, 55oC, and 60oC. The samples were taken out everyday up to four days storage time to investigate Mooney viscosity and bound rubber. In this study, Mooney viscosity increases with increased storage temperature and storage time. The storage temperature at 600C gives an extreme effect on Mooney viscosity of uncured rubber compounds so the measurement cannot be performed. Bound rubber decreases with increased silica content, and the storage temperature and time do not significantly affect the bound rubber content.Keywords:  natural rubber compound, carbon black, silica, mooney viscosity, bound rubbe