Modelling shoot growth and yield of Ceylon tea cultivar TRI-2025 (Camellia sinensis (L.) O. Kuntze)

摘要

The present study was aimed at stimulating the growth and yield of Sri Lankan tea cultivar TRI 2025 grown in different climatic regions in the country. The model was developed and calibrated using weather, crop and soil data collected from different climatic zones. The model is designed to simulate shoot replacement cycle, leaf area of a shoot, shoot growth, dry matter partitioning and tea shoot yield. The model was validated using shoot development and growth data not used for model calibration. These validation data were collected from low, mid and high elevations representing temperature and rainfall gradients in the country. Model calibration showed that thermal time required to initiate the fish leaf, 1st, 2nd and 3rd normal leaf in a tea shoot from the time of natural senescence of the scale leaves were 129, 188, 235, 296 degrees C days, respectively, and a tea shoot reached the harvestable stage after 393 degrees C days. The model simulated leaf area (cm(2)) and fresh weight (g/m(2)) of tea shoots at different developmental stages and locations which were in good agreement with the measured values at the validation stage (R-2 & 0.92 and 0.98, respectively). Similarly, simulated shoot yields (g/m(2)/month) at the validation stage were strongly correlated with the measured values (n = 12, R-2 & 0.58, RMSE = 5-17 g/m(2)/month). Thus, the model can be used to estimate the shoot yield of tea cultivar TRI 2025 grown in different climatic conditions in Sri Lanka. Areas requiring further improvements to the model are also discussed.