Survival and Growth Response of Seedlings to Seed Size Variation of Albizia lebbeck (L.) Benth

Aims: To investigate the influence of seed size variation on seedling growth height, root collar diameter, root length, seedling length, root shoot ratio, number of leafs, leaf area, dry weight and survival of Albizia lebbeck in the nursery.
Place and Duration of Study: The experiment was conducted in the nursery at Malawi College of Forestry and Wildlife between March and September 2014.
Methodology: Seeds were categorized into three groups in regard to their length and weight: large (0.98±0.05 cm) and (0.22±0.02 g); medium (0.64±0.04 cm) and (0.13±0.02 g); and small (0.32±0.05 cm) and (0.09±0.01 g).The treatments were completely randomized into four replications. A total of 600 seeds were used with each treatment having 50 seeds. To improve germination, seeds were mechanically nicked with secateurs.
Results: Seedling height, root collar diameter, root length, seedling length, root shoot ratio, number of leafs, leaf area, dry weight and percentage survival were significantly (P<.001) affected by seed size variation. Large seeds produced higher seedling height (58.4 cm), root collar diameter (5.97 mm), root length (29.7 cm), seedling length (88.1 cm), root shoot ratio (0.51), number of leafs (8.21), leaf area (405.0 cm2 plant-), dry weight (11.3 g plant-) and percentage survival (89.6%) compared to seedling height (43.7 cm), root collar diameter (4.03 mm), root length (20.2 cm), seedling length (63.8 cm), root shoot ratio (0.46), number of leafs (5.93), leaf area (207.3 cm2 plant-), dry weight (7.8 g plant-) and percentage survival (65.2%) of medium seeds and seedling height (29.3 cm), root collar diameter (2.01 mm), root length (12.6 cm), seedling length (41.9 cm), root shoot ratio (0.43), number of leafs (3.66), leaf area (136.8 cm2 plant-), dry weight (5.1 g plant-) and percentage survival (46.1%) of small seeds.There was a significant correlation between seed size and seedling height (P=.05, r=.92), root length (P=.05, r=.93), root collar diameter (P=.05, r=.95), number of leafs (P=.05, r=.95), leaf area (P=.05, r=.90), dry weight (P=.05, r=.81), and percentage survival (P=.05, r=.82). This indicates that seed size could be used as parameter for predicting seedling growth rates in the nursery.
Conclusion: The present study has demonstrated the merits of grading seeds and that use of large size seeds for production of high quality transplants of Albizia lebbeck in the nursery is recommended.