Evaluation of Rubber Tree Clones Under Different Tapping Systems in Northwestern Paraná State, Brazil.

ABSTRACT This study evaluates the potential of rubber tree clones (Hevea spp.) under four tapping systems for the Northwestern region of the State of Paraná with the objective of enhance genetic diversification and increase natural rubber production in this new and promising region for rubber tree cultivation by selecting the better combination of clone and tapping system. The experiment was installed at Guanabara Farm, municipality of Paranapoema, Paraná State, in a split-plot randomized complete blocks experimental design with three replications. In the plots 12 clones were tested, namely RRIM 600 (control), IRCA 18, IRCA 111, IRCA 130, PB 235, PB 252, PB 260, PB 330, IAC 15, IAC 35, IAC 41 and RO 38. The subplot treatments consisted of four tapping systems: 1) ½ S d/4 ET 2.5%, 2) ½ S d/4, 3) ½ S d/7 ET 2.5% and 4) ½ S d/7. Dry rubber production was evaluated over a period of two years. Due to the higher productivity the clones IRCA 130, IRCA 111, IRCA 18, IAC 35, IAC 41, IAC 15, PB 260 and PB 235 are suggested to be planted at a proportion of 5% to 10% of the total area in commercial plantings for more detailed evaluation. Because of their significantly lower productivity, the clones PB 330, PB 252 and RO 38 should not be recommended, as well as the tapping system S d/7 ½ without stimulation