Technological properties of latex and natural rubber of Hevea brasiliensis clones

Abstract

Rubber industry has increased the requirements for quality and uniformity of natural rubber produced in Brazil. Technological properties of latex and natural rubber of clones GT 1, PB 235, IAN 873 and RRIM 600 [Hevea brasiliensis (Willd. Former Adr. de Juss.) Muell.-Arg] were evaluated by standard methods of the dry rubber content (DRC%), percentage of nitrogen (N%) and percentage of ashes (ASH%) in two consecutive years; data were correlated with temperature and precipitation. Properties of latex and natural rubber varied (P < 0.01) as a function of clone type and among tappings. DRC decreased in the beginning of the dry season (May to June) and N% and ASH% increased in the same period. April to June was a critical period, when N% was above 0.60%, out of standards established by the technical standard ABNT/NBR in Brazil. Clone RRIM 600 was less susceptible to climatic variations. Key words: rubber tree, standard methods, productivity, environmental conditions PROPRIEDADES TECNOLÓGICAS DO LÁTEX E DA BORRACHA NATURAL DE CLONES DE Hevea brasiliensisRESUMO: A indústria da borracha está cada vez mais exigente em relação à qualidade e a uniformidade da borracha natural produzida no Brasil. Neste trabalho as propriedades tecnológicas do látex e da borracha natural dos clones de seringueira GT 1, PB 235, IAN 873 e RRIM 600 [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell.-.Arg] foram avaliadas pelos ensaios padrões do conteúdo de borracha seca (DRC%), porcentagem de nitrogênio (N%) e porcentagem de cinzas (CNZ%) por dois anos consecutivos; os dados obtidos foram correlacionados com dados de temperatura e precipitação. As propriedades do látex e da borracha natural variaram (P < 0.01) em função do tipo de clone e entre coletas. O DRC% diminuiu no início da estação seca (maio a junho), enquanto N% e CNZ% aumentaram. O período de abril a junho revelou ser crítico, pois os valores da N% oscilaram acima 0,60%, fora dos padrões estabelecidos pela norma técnica brasileira ABNT/ NBR. O clone RRIM 600 foi menos suscetível às variações climáticas.

Variation of technological properties of field natural rubber lattices from Hevea brasiliensis clones and natural rubber-based compounds

“…Comparison of all the possible pairs of clones means through Tukey tests indicated that there were significant differences in TSC, DRC, and volatilematter content. Variations of lattices properties suggested different performances among clones even at the same agronomic and climatic conditions, as reported in other studies on Brazilian and African NR [4][5][6]14]. Fig.…”

“…N, P, K, Na, Cl and S are mobile in Heveas, while Zn, Cu, Mn, Fe, and Mg are partially mobile. When nutrients are absorbed by a process of constant reutilization, as occurs during leaf senescence, ash content tends to decrease, as observed in February for IAN 873 and IAN 710 [4,6]. Variation of nitrogen content is presented in Fig.…”

“…6 shows the variation of ash content. Ashes in NR latex are related to nonvolatile mineral fraction, including minerals inherent in the rubbery substance such as Ca and Mg [4,6]. Ash content of all the samples was below 0.60%, the maximum specified in ASTM D2227 standard [9].…”

“…Productivity of NR plantations has been improved by incorporating new genetic varieties of Hevea brasiliensis and evaluating the properties of the NR obtained from the existing ones; several studies on the properties of NR obtained from RRIM 600, WG 1, GT 1, IAN 873, FX 3864, and PB 235 clonal varieties harvested in Brazil have been carried out [4][5][6][7][8][9].…”

Desempenho de clones de copa e painel de seringueira no sudoeste do Estado do Mato Grosso

“…Os valores de DRC (Tabela 4), registrados na média de duas coletas realizadas (janeiro e março), variaram de 43,8% (RRIM 600 x IAN 6543) a 64,7% (RRIM 600 x IAN 6158) e ficaram acima dos valores obtidos por Kalil Filho et al (2000), com os clones IAN 6543 e IAN 6158, e por Moreno et al (2005), com GT 1, PB 235, IAN 873 e RRIM 600. De acordo com Moreno et al (2003), as diferenças dos valores de DRC resultaram da grande variação existente nesta propriedade do látex, dependente de sistemas e intensidades de sangria, variações climáticas, clones, práticas de estimulação e tratos culturais.…”