Performance of latex and natural rubber of new rubber tree clones (IAC series)

The rubber industry has increased the requirements for quality and uniformity of the natural rubber (NR) produced in Brazil. Technological properties of latex and NR of new clones IAC (40, 56, 300-303) and RRIM 600 [Hevea brasiliensis (Willd. Former Adr. de Juss.) Muell.- Arg] were evaluated by standard methods of the dry rubber content, percentage of nitrogen-and of ashes in two years. Properties of latex and NR varied (P<0,01) as a function of clone type and among tappings. Dry rubber content decreased in the beginning of the dry season (may to june) whereas the nitrogen and ash conten increased in the same period. It is shown that a critical period is april to june, since the nitrogen content 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.