Simulation and validation of response of ‘shalimar wheat 2’ (Triticum aestivum) to sowing dates and nitrogen levels under rainfed conditions using DSSAT-CSM-CERES-wheat model

A-2 year experiment was carried out at Wadura, Kashmir, Jammu and Kashmir during 2015–16 and 2016–17 in a split-plot design, keeping 3 sowing dates (15 October, 30 October and 15 November) in mainplots and 4 nitrogen levels (0 kg, 50, 100 and 150 kg N/ha) in subplots, to simulate the response of Shalimar Wheat-2 var. wheat (Triticum aestivum L.) to sowing dates and nitrogen levels under rainfed conditions using DSSAT-CSM-CERES-Wheat. The pooled results of 2 years revealed that the highest grain yield of 4.46 t/ha, straw yield of 8.30 t/ha and biological yield of 12.8 t/ha were obtained when sowing was done on 15th October. The grain, straw and biological yields decreased by 17.33, 12.58 and 14.25% with delay in sowing from 15 October to 15 November, respectively. Genetic coefficients of newly evolved wheat cultivar ‘Shalimar Wheat 2’ were generated for calibration and validation of model CERES-wheat Ver.4.6 (DSSAT). The DSSAT-CERES-Wheat model performed well, as revealed by high correlation coefficient (r), low root mean square error (RMSE) and low mean absolute percentage error (MAPE) in simulating the days to anthesis (r, 0.99; RMSE, 3.9; MAPE, 1.84), maturity (r, 0.97; RMSE, 3.9; MAPE, 1.51), leaf area index (r, 0.90; RMSE, 0.2; MAPE, 6.22), grain yield (r, 0.92; RMSE, 0.39; MAPE, 17.85), and biological yield (r, 0.89; RMSE, 1.03; MAPE, 7.71). Also, a good line of fit (1:1) was found between the simulated and observed grain yield with R² of 0.89.