Drought tolerance in upland rice: identification of genotypes and agronomic characteristics/Tolerancia a deficiencia hidrica em arroz de terras altas: identificacao de genotipos e caracteristicas agronomicas

This study aimed to identify upland rice cultivars and elite lines that are tolerant to drought and the agronomic traits associated with this tolerance. Forty-one genotypes were evaluated in a randomized block design with three replications in experiments with and without water stress at the Experimental Station of Emater, in Porangatu, Goias State, in 2011 and 2012. The first experiment was well-irrigated throughout plant development and the second experiment was irrigated only up to 40 days after emergence, after which water stress was imposed. A multivariate analysis using Ward's method was applied, and the genotypes with and without water stress were classified into six and seven clusters, respectively, based on the average yield in the two years of experimentation. The most productive cluster under water stress comprised the genotypes AB062041, Douradao, Guarani, BRS Aimore, and Tangara. The first four genotypes of this cluster were also ranked in the second most productive cluster under well-irrigated conditions. In the selection for drought tolerance, the genotypes that exhibit precocity, less dense panicles, low sterility and greater 100-grain weight under water stress should be prioritized. Keywords: Oryza sativa L., spikelet sterility, earliness, grain weight. O objetivo do trabalho foi identificar a tolerancia a deficiencia hidrica de cultivares e linhagens elites de arroz de terras altas e as caracteristicas agronomicas relacionadas com essa tolerancia. Avaliaram-se 41 genotipos no delineamento de blocos ao acaso, com tres repeticoes, em experimentos com e sem deficiencia hidrica, na Estacao Experimental da Emater em Porangatu, Goias, em 2011 e 2012. O primeiro foi irrigado adequadamente durante todo o desenvolvimento das plantas e o outro apenas ate aos 40 dias apos a emergencia, quando foi aplicada a deficiencia hidrica. Aplicou-se a analise multivariada e pelo metodo de Ward classificaram-se os genotipos em seis e sete grupos, considerando-se os valores medios das produtividades nos dois anos de conducao dos experimentos, com e sem deficiencia hidrica, respectivamente. O grupo mais produtivo sob condicoes de deficiencia hidrica foi composto pelos genotipos AB062041, Douradao, Guarani, BRS Aimore e Tangara. Os quatro primeiros genotipos desse grupo foram tambem classificados no segundo grupo mais produtivo sob condicoes de irrigacao adequada. Na selecao para tolerancia a deficiencia hidrica deve-se priorizar genotipos que apresentem, sob essa