Effect of seed soaking and drying on germination, growth andvigour of Macadamia (Macadamia integrifolia Maiden & Betche)

Macadamia nut (Macadamia integrifolia) is among the world’s premium nuts and is gaining popularity in India due to its high market value. However, its germination is poor and slow owing to the presence of a hard seed coat, often delaying emergence for 5–6 months. The present study evaluated the effect of seed soaking and drying treatments on germination and early growth attributes. Seeds soaked for three days followed by oven drying at 40 °C for 18 hours exhibited significantly earlier germination (47 days) and higher germination percentage (88.13%) compared with the control. These treatments also enhanced seedling growth parameters, including plant height (16.16 cm), stem girth (0.47 cm), number of leaves per plant (11.22), fresh weight (10.73 g), dry weight (4.66 g), vigour index-I (1429.11 cm), and vigour index-II (411.40 g). Correlation analysis revealed that initiation of germination was positively associated with the time required for 50% and complete germination. Overall, soaking macadamia seeds for three days followed by oven drying improved germination efficiency, growth performance, and vigour of seedlings, and can be recommended for commercial propagation.