Simulation of potential yields of new rice varieties in the Senegal River Valley

Irrigated rice in the Sahel has a high yield potential, due to favorable climatic conditions. Simulation models are excellent tools to predict the potential yield of rice varieties under known climatic conditions. This study aimed to (1) evaluate new rice genotypes for the Sahel, and (2) calibrate simulation models to predict potential yield of irrigated rice in the Sahel. Two new inbred lines (ITA344 and IR32307) and one O. sativa × O. glaberrima line (WAS 161-B-9-2) were tested against IR64, an international check, and Sahel 108, locally the most popular rice cultivar. Field experiments were executed at two sites along the Senegal river, Ndiaye and Fanaye, differing in temperature regime and soil type. All cultivars were sown and transplanted at two sowing dates in February and March 2006. Observed grain yields varied from 7 to 10 t ha-1 and from 6 to 12 t ha-1 at Ndiaye and Fanaye, respectively. The number of days until maturity ranged from 119 to 158, depending on cultivar, sowing date and site. Experimental data of one sowing date was used to calibrate both the DSSAT and ORYZA2000 models. According to ORYZA2000, the same cultivars needed 400°Cd more in Fanaye than in Ndiaye to complete their cycle. ORYZA2000 simulated phenology well, but yield was underestimated. After calibrating DSSAT, different sets of genetic coefficients gave similar results. Genetic coefficients that reflected the observed phenology well resulted in lower than observed yields. Crop growth simulation is a powerful tool to predict yields, but local calibration at the same sowing date is needed to obtain useful result