Variations in growth, crown architecture, and leaf functional traits in a progeny trial of <i>Tectona grandis</i> L.f. in Indonesia

Teak (Tectona grandis) is a valuable tropical timber species, but knowledge about its environmental adaptability for tree breeding is limited. Progeny trial is crucial for improving breeding materials as progeny performance and resilience to environmental stresses can be assessed for future breeding effort. In this study, we examined the variations in growth, crown architecture and leaf traits in a progeny trial in Indonesia. We retained the best components to explain the relationships among 14 traits and analyzed their genotypic correlations. Our results indicate that family differences contribute to the variation in leaf functional traits such as phosphorus content and SPAD value, which indicate chlorophyll content. Further, we identified three major trait axes that explained most of the trait variations by principal component analysis. The first and second axes represented the leaf economics spectrum, and variations related to tree size, respectively, while the third axis represented venation traits. Additionally, leaf chlorophyll content indicated by SPAD value was an effective tool for evaluating progeny performance because of its strong correlations with growth rate and leaf nutrient contents. These findings provide valuable insights for future progeny trial planning in breeding programs toward enhancing resilience and productivity in teak.