Behaviour of upland rice varieties at different plant densities, under and without supplemental irrigation

Abstract

Four experiments were carried out in a cerrado soil to study the effect of row spacing and seed density on rice (Oryza sativa) yield and some byometric characteristics, with and without supplemental sprinkler irrigation. Two experiments used the Araguaia variety and the other two, the Guarani variety. Irrigation enhanced in 90 and 35% the yield of the varieties Araguaia and Guarani, respectively. Irrigation significantly affected biometric characteristics. The highest yield of Guarani v. was obtained with 30 cm row spacing and density of 130 seeds per m², and its harvest index (HI) was linearly and positively correlated with grain yield. The highest yield of Araguaia v. was obtained with 40 cm spacing, independently of the density and presence of irrigation. The variety Guarani showed to be more competitive than the Araguaia, having smaller HI and its grain yield being more affected by plant population.