Morphological and physiological responses to drought stress in a set of Brazilian traditional upland rice varieties in post-anthesis stage

Abstract

Among the abiotic stresses that can affect the growth and development of the crop, drought is considered one of the main factors that can reduce the global food production. The goal of this study was to analyze the effect of drought stress on several morphological and physiological parameters in ten traditional upland rice varieties. The experimental design set up in a factorial scheme 10 x 2 (varieties x treatments) with four replicates under greenhouse conditions. At the start of the reproductive stage, rice varieties were submitted to control and drought conditions during 30 days and evaluated for physiological and morphological parameters. Rice varieties were considered as tolerant and susceptible to drought stress based on the classification proposed by five different stress tolerance indices (SSI, TOL, SSSI, DYI and DTE). The results suggest that the adopted indices associated with multivariate analysis from the parameters analyzed are efficient to discriminate between tolerant and susceptible rice varieties to the drought stress. Catetão and Piauí were considered as the most tolerant, while Quebra Cacho and Mira were the most susceptible. The analysis of morphological and physiological parameters through multivariate analyses revealed as an important tool to assist breeders in the identification of tolerant and susceptible varieties and to characterize how the varieties alter their metabolism to withstand the drought stress.