Effect of low frequency harvesting in Hevea brasiliensis on major raw rubber properties

Harvesting latex, a key activity in the production of natural rubber (NR), involves repeated tapping of the bark on the main trunk of the trees. Low frequency harvesting (LFH) systems are only economically feasible with the use of Ethephon (ET) which stimulates the tree to provide high yield per tap as a compensation for the yield loss due to lowering the tapping frequency. Ethephon concentration and its frequency of application may vary with the frequency of harvesting used. Latex samples were collected from genotypes; RRIC 100, RRIC 102, RRIC 121 and RRIC 130 harvested under S/2 d2, S/2 d3, S/2 d4 and S/2 d6 (i.e. tapping half of the spiral of tree once in two, three, four and six days, respectively) systems were processed into lace crepe and assessed for raw rubber properties viz. initial plasticity (Po), plasticity retention index (PRI), Mooney viscosity (VR), colour, nitrogen and ash content.

 

No significant differences were observed among different LFH systems with respect to each raw rubber property tested. However, clonal differences in those raw rubber properties were prominent. Therefore, the study revealed that the low frequency harvesting systems tested with Ethephon stimulation do not have any effect on the quality of raw rubber produced.