Water Productivity of Rice Genotypes with Irrigation and Drainage

Abstract

Abstract The aims of this study were: (i) to evaluate the agronomic characteristics of thin‐grain rice genotypes with high yield potential under irrigation conditions; (ii) to quantify water productivity (WP) in thin‐grain rice genotypes, based on crop evapotranspiration (ET C ) and irrigation and surface drainage control. Eight genotypes were planted: four varieties, two promising lines and hybrid Clearfield XL745 and IRGA. Direct dry seeding was carried out mechanically at a density of 80 kg ha ‐1 for the varieties and 32 kg ha ‐1 for the hybrid; drainage was performed every 9.3 m inside of the border. The results indicate that there are significant differences ( P > 0.05) among genotypes for grain yield and its components, except for lodging. The varieties and promising rice lines evaluated expressed good productive capacity, but they were surpassed by 19% by the average productivity recorded by the variety IRGA and the hybrid Clearfield. The variation in water demand based on ET C is evident in the optimal irrigation depth applications of 264 mm for the hybrid and 318 mm for the intermediate‐cycle genotypes. The border irrigation method with drainage troughs significantly increases water productivity based on the applied irrigation (WP I ), averaging 2.0 kg m ‐3 . © 2018 John Wiley & Sons, Ltd.