Seedlings growth from different age of rubber trees (Hevea brasiliensis Muell. Arg.) experiencing repeated leaf fall

Abstract

The budding technique propagation requires rootstock, which are raised from rubber seeds. Due to repeated leaf fall disease since 2015, seed production dropped and threatened the rubber-replanting program. Amid this situation, young trees may be a temporary source of the seeds for rootstocks, which under normal conditions is not recommended. To test this hypothesis, a comparison of germination rate, seedling growth, and biomass accumulation of the seeds from young and mature PB 260 rubber trees was carried out at Sungei Putih Research Unit, Indonesian Rubber Research Institute, North Sumatra, Indonesia. The study showed that the germination rate of the seeds was low i.e. 7.23 + 2.96 % of young plants and 21.96 + 13.51 % of mature plants respectively, both were below normal values around 70 – 80%. After germination, no significant difference was found in the growth of seedlings from young trees and their mature counterparts. The root/shoot ratio exhibited no significant difference between the two types of seedlings observed, indicating a similar biomass accumulation capability. In the condition when seed supply was limited due to leaf fall disease, the seeds of young trees might be used as a temporary source with standard selection protocols should be implied.