Developing Genetic Coefficients of Sorghum Cultivars Using Gencalc and Glue Genetic Coefficient Estimators in DSSAT

DSSAT (Decision Support System for Agrotechnology Transfer) is a software system used for crop growth and development, soil and water balance, nutrient cycling, climate change impact simulations and precision agriculture. The objective of this study was to calibrate and validate the sorghum cultivars TNAU sorghum CO 30 and K12 under various sowing windows and fertilizer applications. CERES-Sorghum model (DSSAT v 4.7.5) was calibrated and validated using experimental field data obtained from Tamil Nadu Agricultural University, Coimbatore. The derived genotype co-efficients of sorghum cultivars simulated the phenology, growth and yield accurately well under various sowing windows and nitrogen levels. The nRMSE (Normalised Root Mean Square Error) values for simulations for grain yield were 2.4 per cent and 8.8 per cent for TNAU sorghum CO 30 and K12, respectively. The mean simulated grain yield was 3127 kg/ha against the observed grain yield of 3052 kg/ha in TNAU CO 30 sorghum. The mean observed grain yield was 3312 kg/ha against the observed grain yield of 3020 kg/ha K 12. The model satisfactorily simulated the phenology and yield of sorghum cultivars, and hence it can be used in undertaking suitable management practices and yield prediction under changing climatic conditions in the western region of Tamil Nadu.