Propagation of Antidesma alexiteria and Syzygium caryophyllatum, two underexploited fruit plants in Sri Lanka: Effect of cutting types, potting media and auxin application

Antidesma alexiteria and Syzygium caryophyllatum are two fruit species found in Sri Lanka of which the commercial development potential has not been fully identified. To bring these fruit species back into cultivation, establishment of suitable propagation systems for mass propagation is important. Therefore, this research was designed to identify suitable potting media, stem cutting types and requirement of auxin for successful vegetative propagation of the two fruit species. Softwood, semi-hardwood and hardwood cuttings of the fruit trees were planted in three potting media (M1 – topsoil, sand 1:1, M2 – topsoil, sand, compost 1:1:1 and M3 – topsoil, sand, coir dust 1:1:1) under two treatments; T1 – with plant growth reg­ulator indole-3-acetic acid (IAA) and T0 – controls without IAA. Each treatment was conducted with 15 replicates. The cuttings were planted in individual propagators and were kept in a net house of 50% shading under room temperature. Growth performance of the cuttings was monitored in regular intervals (every 28 days) for a period of six months. According to sprouting, survival, and growth performance, both softwood and semi-hardwood cuttings are suitable for vegetative propagation of A. alexiteria. The M3 medium showed 100% sprouting and survival but with respect to overall growth performance, the M1 medium was the most suitable for softwoods of A. alexiteria without auxin. Sprouting and survival of semi-hardwood cuttings were 100% with high values of growth parameters in M3 under T1 treatment. The M1 medium without auxin can be recommended for better performance of softwoods while M3with auxin is for semi-hardwoods of A. alexiteria. Softwoods, semi-hardwoods and hardwoods can be recommended for vegetative propagation S. caryophyllatum in M1 medium. Both softwood and semi-hardwood cuttings under T1 treatment expressed higher sprouting and survival percentages while semi-hardwood cuttings under T1 treatment have shown the highest sprouting and growth performance. Hence, semi-hardwood cuttings with auxin can be con­sidered as the best planting material for vegetative propagation of S. caryophyllatumwhile M1 is the best medium. The vegetative propagation of S. caryophyllatum and A. alexiteria through stem cuttings can be recommended as suitable mass propagation method for the purpose of commercialization.