Variation in vegetative phenological traits among teak (Tectona grandis L.) genotypes in a clonal seed orchard

Teak (Tectona grandis L.) is a valuable tropical timber species known for its durability, strength, and economic significance. Clonal seed orchards (CSOs) are crucial for improving genetic gain and seed quality. However, phenological variation among clones influences synchronization and productivity. This study evaluated vegetative phenophases and genetic parameters among teak clones in a 45-year-old CSO at Karka, Karnataka. Fifteen teak clones representing northern, central, and southern provenances were assessed for leaf shedding initiation, leafless period, and leaf flushing traits through fortnightly observations from May 2024 to April 2025. Results revealed significant clonal differences across all vegetative phenophases. Northern clones exhibited delayed leaf shedding and prolonged dormancy, whereas southern and central clones showed earlier leaf flushing and shorter leafless periods, reflecting adaptation to local climatic conditions. Genetic analysis indicated high heritability and genetic gain for leaf flushing initiation (78.04%, 52.66%) and duration (73.23%, 27.16%), suggesting strong genetic control. Schematic phenograms illustrated temporal variation among clones, confirming distinct growth rhythms and genotype-specific responses to environmental cues. Vegetative phenology in teak is predominantly genotype-governed with moderate environmental influence. Traits such as leaf flushing initiation and duration are reliable for selecting superior clones with synchronized growth and enhanced adaptability, supporting effective teak improvement and sustainable orchard management.