Effect of Seedling Early Growth on the Seed Size of Red Bark Oak (Cyclobalanopsis gilva (Blume) Oerst.)

The primary shoot length of 1-month-old seedlings of Cyclobalanopsis gilva was used as a parameter to determine the relationship between further early growth of seedlings and seed size in this study. Due to the high variation existing both in the growth of primary shoots and in seed size, six and five classes were created for grouping, respectively.
Shoots in the largest size class were 25% longer than those in the smallest size class. The diameter of seeds in the smallest size class was 1.12 cm, with a length 77% of that of seeds in the largest size class. After being raised in the greenhouse for 9 months, the height, root collar diameter, and survial rate of seedlings in different classes were investigted. Comparing these parameters between the smallest and largest size classes, the former were 67% shorter in seedling height, 61% smaller in root collar diameter, and 75% lower in survival rate than the latter. Seedling derived from seeds smaller than 1.11 cm in diameter had stunted epicotyls and failed to grow further. The correlation analysis among these parameters showed that primary shoot length appeared to be positively related to seed size as measured by diameter, primary leaf number and height of growth of
seedlings. Seedling with longer primary shoots were from larger seeds and grew stronger, whereas seedlings with shorter shoots were from smaller seeds and grew poorly with low survival rates. This finding suggests that C. gilva seeds smaller than 1.10 cm should be discarded . The remaining larger seeds should then produce uniform growth and stronger seedlings with 9 high survival rate which will reduce the cost of raising seedlings and provide good quality seedlings for reforestation.