# Joint Selection for Growth and Leaf Color in Superior Trees of Sapium discolor in Fujian Province, China

## TL;DR

This study identifies superior Sapium discolor trees in China with fast growth and red leaves, showing the benefits of clonal selection for breeding.

## Contribution

The paper demonstrates effective clonal selection for growth and leaf color in Sapium discolor, achieving notable genetic gains.

## Key findings

- Sapium discolor showed early fast growth with moderate heritability for height and diameter.
- Clonal selection achieved genetic gains of 13.1% in height, 10.1% in diameter, and 8.3% in red coloration.
- Non-additive genetic effects were significant, suggesting the importance of genotype × environment interactions.

## Abstract

Sapium discolor is a valuable native species in southern China, valued for its rapid growth and vibrant foliage, and widely used in ecological restoration and landscaping. To identify superior propagation materials with fast growth and red leaves, regional open-pollinated progeny trials of 10 elite trees were established in Nanping, Sanming, and Zhangzhou (Fujian Province) in 2015. Growth (tree height and diameter) was monitored from 2015 to 2023, and leaf color (the proportion of red in leaf color) was assessed in 2024. The species showed early fast growth, with mean tree height and diameter at breast height (DBH) reaching 7.98 m and 9.99 cm at six years, then slowing. Family-level phenotypic variation was limited. ANOVA revealed highly significant differences among families for growth traits from 2016 onward and for leaf color in 2024. Broad-sense heritability was moderate for 2023 tree height (0.3839), DBH (0.1879), and 2024 leaf color (0.2102), with low narrow-sense heritability, indicating non-additive genetic effects. Clonal selection based on genotypic values achieved notable genetic gains, especially for growth. One superior clone combined improvements in height (13.1%), diameter (10.1%), and red coloration (8.3%). These results highlight the value of clonal selection and the need to consider genotype × environment interactions in breeding programs.