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Photosynthetic behaviour during the leaf ontogeny of rubber tree clones[Hevea brasiliensis (Wild. ex. Adr. de Juss.) Muell. Arg.], in Lavras, MG
Miguel, Aurélio Antas;Oliveira, Luiz Edson Mota de;Cairo, Paulo Araquém Ramos;Oliveira, Davi Melo de;
Ciência e Agrotecnologia , 2007, DOI: 10.1590/S1413-70542007000100014
Abstract: this work proposed to investigate changes in the photosynthetic behavior during the leaf ontogeny of the during the leaf development. up to the 32nd day of leaf age (stage b2), the net photosynthesis was negative due to the inefficiency of the photosynthetic system, and this fact was justified by the following factors: low chlorophyll content, less stomatal conductance, high rubber tree clones pb 235, rrim 600 and gt 1, in lavras, mg. the experiment was performed in 2004, between may and july, under field conditions, at the universidade federal de lavras. during the leaf ontogeny, the following characteristics were evaluated: chlorophyll content, gaseous exchanges and chlorophyll fluorescence. the clones presented similar profiles of alterations in the physiological characteristics internal co2 levels and low chlorophyll fluorescence. from the 37th day of leaf age, net photosynthesis became positive and gradually higher, stimulated by the increases in the chlorophyll contents, photochemical efficiency of photosystem ii, carboxylation efficiency, stomatal conductance, transpiration and water use efficiency. among the clones, photosynthetic behavior was similar, reaching maximum performance on the 57th day of leaf age (stage d), when clone rrim 600 showed the highest net photosynthesis, differing from the clones pb 235 and gt 1.
Analysis of genetic diversity in early introduced clones of rubber tree (Hevea brasiliensis) using RAPD and microsatellite markers
Korakot Nakkanong,Charassri Nualsri,Sayan Sdoodee
Songklanakarin Journal of Science and Technology , 2008,
Abstract: Genetic analysis in 53 early introduced clones of rubber tree (Hevea brasiliensis) collected from different areas inSouthern Thailand was performed using RAPD (Random Amplified Polymorphic DNA) and microsatellite markers. Seventeencultivated clones (34 samples) were also included to compare DNA patterns. DNA was isolated from leaf samples usingCTAB buffer. One hundred and ninety two 10-base oligonucleotide primers for RAPD were first screened and 8 primers(OPB-17, OPN-16, OPR-02, OPR-11, OPZ-04, OPAD-01, OPAD-10 and OPAD-12) were chosen for genetic variationanalysis in 87 individual plants. Seventy amplification fragments were obtained from the 8 primers with an average of 8.75fragments for each primer. From all fragments 55 were polymorphic fragments (78.57%). One RAPD primer (OPAD-01)yielded a 700-bp fragment that was present only in the Tjir1 clone. Four microsatellite primer pairs (hmac4, hmct1, hmct5and hmac5) produced a total of 44 amplified fragments with an average of 14.67 fragments per primer, of which 37 werepolymorphic (84.09%) while hmac5 produced only monomorphic fragments. A phenogram showing genetic similaritiesamong rubber trees was constructed based on the polymorphic bands of the RAPD and microsatellite analyses using UPGMA(Unweighted Pair-Group Method Using Arithmetic Average). Cluster analysis was performed by the NTSYS Version 2.1program. The results from phenogram showed that the 87 rubber clones could be clustered into 6 groups with similaritycoefficients ranging from 0.541-1.000. Cultivated clones revealed more narrow genetic diversity compared to the early introducedclones. The clustering was not correlated with the geographical location of the collected samples.
Assessment of growth and yield performance of rubber tree clones of the IAC 500 series
Gon?alves, Paulo de Souza;Scaloppi Júnior, Erivaldo José;Martins, Maria Alice;Moreno, Rogério Manoel Biagi;Branco, Roberto Botelho Ferraz;Gon?alves, Elaine Cristine Piffer;
Pesquisa Agropecuária Brasileira , 2011, DOI: 10.1590/S0100-204X2011001200009
Abstract: the objective of this work was to evaluate the performance of 15 clones of the iac 500 series of hevea brasiliensis, developed at instituto agron?mico (iac), over a 12-year period, in the northwest region of s?o paulo state, brazil. the 15 new clones evaluated are primary clones obtained from selected ortets within half-sib progenies. the clone rrim 600, of malaysian origin, was used as the control. dry rubber yield performance over a four-year period, mean girth at the tenth year, girth increment before and during tapping, thermal properties of the natural rubber produced and other characters of the laticiferous system were evaluated. forty percent of the clones were superior in comparison to the control for yield. clone iac 500 recorded the highest yield (66.81 g per tree per tapping) over four years of tapping, followed by iac 502 (62.37 g per tree per tapping), whereas the control recorded 48.71 g per tree per tapping. all selected clones were vigorous in growth. the natural rubber from this iac clones showed thermal stability up to 300oc. no differences were observed in the thermal behavior of rubber among the iac series and the rrim 600 clones. the clones iac 500, iac 501, iac 502, iac 503 and iac 506 are the more promising for small-scale plantations, due to growth and yield potential.
Intensidade do mal das folhas em plantas jovens e adultas de seis clones de seringueira na regi?o do Vale do Ribeira: South American leaf blight intensity evaluated in six clones of young and adult rubber trees in the Vale do Ribeira region, S?o Paulo state, Brazil
Furtado, Edson Luiz;Menten, José O.M.;Passos, José Raimundo;
Tropical Plant Pathology , 2008, DOI: 10.1590/S1982-56762008000200007
Abstract: rubber tree clones present different intensity of symptoms, depending on their age. this is mostly clearly seen inthe presence or absence of old leaves with ascopores, corresponding to flows of new and susceptible leaves. the objective of this work was to evaluate the intensity of symptoms of south american leaf blight (salb) in six rubber tree clones, one and eight years old, in the vale do ribeira region, s?o paulo state. the results showed that clones fx 3864, rrim 600, ian 873 and ian 717 suffered more attacks when young, and rrim 600, ian 717 and fx 3864 when adult. the clone ian 873 showed the smallest amounts of disease in the adult phase, due to uniform change in the leaves and a compact flow of new leaves, which happened during a season that was unfavorable to pathogen infection, presenting the phenomenon of avoidance or evasion in time.
Leaf blade quantitative anatomy of sugarcane cultivars and clones
Ferreira, E.A.;Ventrella, M.C.;Santos, J.B.;Barbosa, M.H.P.;Silva, A.A.;Procópio, S.O.;Silva, E.A.M.;
Planta Daninha , 2007, DOI: 10.1590/S0100-83582007000100003
Abstract: the objective of this study was to make a quantitative assess of the anatomic characteristics of leaf blade of the sugarcane cultivars rb855113, sp80-1842, sp80-1816, rb867515 and clone rb957689 presenting different sensitivity to the mixture of sodium trifloxysulfuron + ametryn herbicides. compared to the other cultivars assessed, rb855113 cultivar, considered more sensitive to the herbicide mixture, presented relevant differences such as greater proportion of bulliform cells, greater tissue proportion in the transverse section of the leaf blade, greater stomata and trichome density on both surfaces, thinner epidermis on the adaxial surface and length of stomata on both surfaces. the external paraclinal wall of the bulliform cells was thinner than in the common epidermis cells in all the genotypes on the adaxial and abaxial surfaces. multivariate analysis of the data on the variables considered most relevant to explain the herbicide penetration singled out the sensitive rb855113 from the other materials. such characteristics can explain the greater penetration, and consequently, greater sensitivity of this cultivar to the sodium trifloxysulfuron + ametryn mixture.
Repeatability of yield and girth growth traits in rubber tree clones of series IAC 300  [PDF]
Adriano Tosoni da Eira Aguiar,Paulo de Souza Gon?alves,Erivaldo José Scaloppi Junior,Juliano Quarteroli Silva
Crop Breeding and Applied Biotechnology , 2006,
Abstract: This study aimed to estimate the repeatability coefficients, to compare the efficiency of methodologies used inthe estimation process, and further to determine the minimal number of evaluations in the selection of rubber tree [Heveabrasiliensis (Willd. ex Adr. de Juss.) Muell. - Arg.] clones. The following methodologies were used: analysis of variance;principal component analysis based on the correlation matrix together with the phenotypic variances and covariance matrix;and the structural analysis. The r values for girth growth varied from 0.77 to 0.79 and rubber yield from 0.39 to 0.52. It wastherefore admitted that the principal component method based on the correlation matrix as well as for the phenotypicvariances and covariance matrix are the most efficient to estimate the coefficient of repeatability. At an accuracy of 90% and80%, two measurements of girth growth and four to six measurements of rubber yield would be necessary for the selection ofrubber tree clones, respectively.
Leaf anatomy and morphometry in three eucalypt clones treated with glyphosate
Tuffi Santos, LD.;Sant'Anna-Santos, BF.;Meira, RMSA.;Ferreira, FA.;Tiburcio, RAS.;Machado, AFL.;
Brazilian Journal of Biology , 2009, DOI: 10.1590/S1519-69842009000100016
Abstract: this work aimed to evaluate the effects of simulated drift of glyphosate on the morphoanatomy of three eucalypt clones and to correlate the intoxication symptoms on a microscopic scale with those observed in this visual analysis. the effects of glyphosate drift were proportional to the five doses tested, with eucalyptus urophylla being more tolerant to the herbicide than e. grandis and urograndis hybrid. the symptoms of intoxication which were similar for the different clones at 7 and 15 days after application were characterized by leaf wilting, chlorosis and curling and, at the highest rates, by necrosis, leaf senescence and death. anatomically glyphosate doses higher than 86.4 g.ha-1 caused cellular plasmolysis, hypertrophy and hyperplasia, formation of the cicatrization tissue and dead cells on the adaxial epidermis. the spongy parenchyma had a decrease, and the palisade parenchyma and leaf blade thickness had an increase. the increased thickness in leaf blade and palisade parenchyma may be related to the plant response to glyphosate action, as a form of recovering the photosynthetically active area reduced by necroses and leaf senescence caused by the herbicide.
Biological cycle of Tenuipalpus heveae Baker (Acari, Tenuipalpidae) on leaflets of three rubber tree clones
Feres, Reinaldo José Fazzio;Del'Arco, Marcelo;Daud, Rodrigo Damasco;
Revista Brasileira de Entomologia , 2010, DOI: 10.1590/S0085-56262010000200013
Abstract: life cycle of tenuipalpus heveae baker (acari, tenuipalpidae) on leaflets from three rubber tree clones. the biological cycle of tenuipalpus heveae baker, 1945 (tenuipalpidae), a potential rubber tree pest mite, was studied by the observation of individuals reared on leaflets of the clones gt 1, pb 235 and rrim 600, in controlled environmental conditions. three daily observations were done of 60 eggs on leaflets from each clone in order to verify the development of immature stages and the female oviposition. the fertility life table was constructed based in the collected data. mites reared on pb 235 had faster rate of development, requiring less time in days, to double its population in number (td), and had the highest values for egg production, female longevity, net reproductive rate (ro), intrinsic rate of natural increase (rm) and finite rate of increase (λ). lower reproductive values and the longest time necessary to reach adult stage were recorded for the mites on gt 1. in all studied clones, the deutonymphal phase had the highest viability, while the larval phase had the lowest, highlighted by the survivorship curve that indicated high mortality during this life stage. the clone pb 235 allowed the most suitable conditions for the development of t. heveae, followed by rrim 600, while gt 1 was the less suitable substratum to rear this mite species.
Nonpreference of the lace bug Leptopharsa heveae Drake & Poor (Heteroptera: Tingidae) for rubber tree clones
Lara, Fernando M.;Tanzini, Marcel R.;
Anais da Sociedade Entomológica do Brasil , 1997, DOI: 10.1590/S0301-80591997000300003
Abstract: to determine the resistance of rubber tree clones (hevea brasiliensis) to leptopharsa heveae drake and poor (heteroptera: tingidae) a trial was held in itiquira, mt, in 1994/95 by comparing the following clones: avros 2037, fx 4037, gt 1, harbel, iac 207, ian 4493, ian 717, ian 873, ro 38, and ro 46. free choice and no choice trials involving preference for oviposition and feeding were carried out under field and laboratory conditions. the symptoms caused by the insects, number of excrements, number of eggs/female/leaflet, mortality rate, and number of insects/leaflet were scored. the results showed that clones fx 4037, ro 38 and ro 46 were resistant by nonpreference for feeding and oviposition, whereas gt and ian 873 were the most susceptible.
Agronomical performance and profitability of exploitation systems in four rubber tree clones in S?o Paulo state
Silva, Juliano Quarteroli;Gon?alves, Paulo de Souza;Scarpare Filho, Jo?o Alexio;Costa, Reginaldo Brito da;
Bragantia , 2010, DOI: 10.1590/S0006-87052010000400009
Abstract: the exploitation or tapping of the rubber tree, hevea brasiliensis (willd. ex adr. de juss.) muell. arg. is one of the most important cultural practices in determining useful life, yield and accounts for a major part of the total production costs in rubber farming. the objective of this work was to evaluate yield performance and economic aspects of rubber tree clones submitted to diverse tapping systems. the trial was placed in guararapes city, s?o paulo state, brazil, in a randomized block design with split-plot in time. the plots consisted of the ian 873, pr 261, rri m 600 and rri m 701 clones. the tapping systems consisted the subplots, where: ?s = tapping of half spiral cut; d/2, d/3, d/4, d/5 and d/7 = tapping every 2, 3, 4, 5 and 7 days, respectively; 11 m/y = tapping during eleven months per year; et = ethephon (stimulant); pa = panel application; la = lace application; 8/y = eight applications per year. the five experimental years were the sub-subplots and the ?s d/2 system was used as control. the analyzed variables were girth, dry rubber yield, tapping panel dryness and economic profitability. the ?s d/3 et 2.5% and ?s d/4 et 2.5% tapping systems provide the highest yield and profitability per hectare per year for the rri m 600 and pr 261 clones. for the ian 873 and rri m 701 clones the yield superiority occurs in high tapping frequency; however the best profitability is obtained in the ?s d/7.et 2.5% system.
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