Effects of ethrel stimulation with different concentrations on yield and physiological parameters of rubber tree Dafeng 95

ObjectiveIn order to provide reference for rubber tree Dafeng 95 to design appropriate tapping system,rubber yield and physiological parameters related to rubber producing of rubber tree Dafeng 95 with ethrel stimulation with different concentrations were analyzed.MethodRubber tree Dafeng 95 being tapped for three years were used as material. Dafeng 95 was tapped with half spiral upward cut every three days(S/2d3),stimulated by ethrel with different concentrations(0,0.25%, 0.50%and 0.75%). Parameters including dry rubber yield,dry rubber content,contents of latex thiol,sucrose,inorganic phos-phorus and magnesium ions,initial flow rate,plugging index under different treatments were analyzed.ResultThe dry rubber net yield increment rate of Dafeng 95 under 0.25%and 0.50%ethrel stimulation were 15.3%and 26.2%respectively,but when the ethrel concentration increased to 0.75%,the yield were not increased obviously as the concentration went up,and the dry rubber content were decreased significantly(P<0.01). Inorganic phosphorus content continued rising significantly(P<0.05,the same below),initial flow rate,plugging index,contents of latex thiol,sucrose and magnesium ions were decreased . The dry rubber content of Dafeng 95 stimulated by ethrel had significantly negative correlations with ethrel concentration(R=-0.8847), and significant positive correlations were found between dry rubber yield and ethrel concentration(R=0.9705).ConclusionThe low frequency tapping system S/2d3 with 0.25%and 0.50%ethrel stimulation for rubber tree Dafeng 95 after being tapped for three years can achieve suitable yield increase. The tapping panel dryness rate does not increase obviously. And this tapping system has light impact on rubber tree growth. Therefore it can be applied to planting of rubber tree Dafeng 95.