Tolerance to drought in rice cultivars in Southern Cerrado area from Tocantins state, Brazil

The rice is large-scale cultivated in a wide range of edaphic and climatic conditions, compounding an alternative source for the increase in food production worldwide. The present study assessed the traits related to productivity, in rice genotypes under conditions of irrigation and water stress, in Gurupi municipality, Southern region from Tocantins state. We evaluated agronomic attributes (number of tillers and panicles, number of grains per panicle and productivity), besides the index of drought sensitivity. The selection of superior genotypes and traits that may serve for the differentiation among the genotypes in this stress condition is essential to create more tolerant materials. Among the most productive genotypes, we highlight the 'Quebra Cacho' that besides presenting relatively high productivities for both culture conditions, also presented a low index of drought sensitivity, ratifying itself as one of the most productive ones and adapted to this culture condition. The number of tillers by square meter did not present differences among the genotypes in both environmental conditions, but in some cases, there was a decrease under the condition of water stress. The number of grains per panicle evidenced great variation between the environments, with a decrease under the stress condition.