MORPHOLOGICAL AND PHYSIOLOGICAL TRAITS OF UPLAND RICE CULTIVARS AFFECTED BY WATER DEFICIT

Abstract

The use of drought-tolerant cultivars is a promising strategy to minimize the effects of water deficits on upland rice productivity. Therefore, it is important to establish an adequate methodology to evaluate the performance of upland rice cultivars under water deficit. In this study, one evaluated the effects of water deficit on morphological and physiological traits of two upland rice cultivars, in a greenhouse, in soil columns, using a phenotyping platform named SITIS. The experiment occurred in a complete randomized block design, in a split plot scheme with four replications. The main plots consisted of a well-irrigated treatment with daily replacement of 100% evapotranspired water and four water restriction regimes (daily replacement of 20%, 40%, 60% and 80% evapotranspired water at the well-irrigated treatment) and, the subplots, of the Douradão and BRS Soberana cultivars, which are tolerant and sensitive to water stress, respectively. It is feasible to use the SITIS platform and the proposed protocol (water regimes) to evaluate upland rice cultivars for tolerance to water stress. Under water deficit, the Douradão cultivar restricted its transpiration and showed harvest index, grain yield and water use efficiency higher than the BRS Soberana cultivar.