In this study, various concentrations of sodium alginate solutions and calcium chloride solutions were tested in order to optimize the size, shape and texture of alginate synthetic seeds or beads for Acacia hybrid bud-sprouting. The shoot buds and axillary buds from in vitro Acacia hybrids, as explants were encapsulated with 2 to 5% sodium alginate (w/v) in the Murashige and Skoog (MS) free of calcium salt solution solvent and exposed to 25 to 100 mM calcium chloride solution (CaCl 2 .2H 2 O). Rounded beads were observed by the encapsulation with alginate 3% and exposed to 75 to 100 mM CaCl 2 .2H 2 O combinations and; the encapsulation with alginate 4 to 5% and exposed to any CaCl 2 .2H 2 O combinations. The produced synthetic seeds were then tested on the plantlets regeneration ability. The germination rate was within 73.3 to 100% in the duration of 6 to 20 days. It showed that encapsulation at any alginate concentrations and exposed to any of the CaCl 2 .2H 2 O concentrations, gave high germination frequency. These plantlets could then be used as the source of explants for the subsequent experiments. The synthetic seeds have the possibility of being an alternative planting material meant for forestry sector in the future, especially for the highly demanded species.

Eucalyptus spp. is an important species in the worldwide quality tropical hardwood sector, which has also gained significance in Sabah and Sarawak, Malaysia since the first large plantations established in 2008s. In October 2018, the trial planting of Eucalyptus hybrid (E. grandis x E. urophylla) and Eucalyptus pellita F. Muell was conducted in Hulu Sedili Forest Plantations, Kota Tinggi, Johore a tropical site with year-round high rainfall and humidity. The E. hybrid were formerly raised using tissue culture technique in the laboratory, Forest Research Institute Malaysia (FRIM) using the plantlets introduced from Tawau, Sabah. While the E. pellita seedlings were conventionally raised from seeds obtained from Seed Production Areas in Sabah Softwood Bhd, Tawau. After 18 months, it was clear that diameter, height growth and periodic increments of E. hybrid out performed E. pellita in the humid tropical environment. The average diameter at breast height, total height, periodic annual diameter and height increments of E. hybrid were significantly different in comparison with E. pellita. The initial vegetative measurement revealed the growth performance of Eucalyptus hybrid with respect with achieved diameter at breast height and total height was higher as compared with Eucalyptus pellita with good survival rate of greater than 90 percent.

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