Yield performance of the IRR 300 series rubber clones in South Sumatra

The growth and yield of rubber tree is determined by three factors i.e. genetic, environmental and the interaction between genetic and environmental factors. Therefore, the selection process of new genotypes should be carried out under different agroclimatic conditions. This is part of a series of selection processes consisting of seedling evaluation trial (SET), small scale clone trial (SSCT), large scale clone trial (LSCT) and adaptation trial. The purpose of this study was to evaluate the yield performance of the IRR 300 series rubber clones in South Sumatra. The IRR 300 series rubber clones have been evaluated under SET and SSCT at Sungei Putih Research Centre, Deli Serdang, North Sumatra. The selected clones were further evaluated at Sembawa Research Centre, Banyuasin, South Sumatra. Twenty two selected clones of IRR 300 series and BPM 24 as control were planted in a large scale clone trial. Tapping was initiated in 2019 with S/2 d3 tapping system. The average yield from five years of tapping without and with ethephon stimulation showed there are seven clones that have higher yield than BPM 24. IRR 309 and IRR 310 were two highest-yielding clones where the average yield with ethephon stimulation reached 53.2 and 52.7 gram per tree per tapping respectively. The result from laboratory and green house evaluation as well as field observation of IRR 300 series rubber clones showed that these clones were resistant to Corynespora and Colletotrichum and moderate-resistant to Pestalotiopsis leaf fall disease. © Published under licence by IOP Publishing Ltd.