Water deficit in the soybean breeding

The climate unpredictability causes long periods of drought, becoming the main risk factor in soybeans production fields and consequent losses to farmers in Brazil and worldwide. As sessile organisms, plants are constantly challenged by a wide range of environmental stresses, including drought. Growth constraints and stress due to these environmental changes result in reduced yield and significant harvesting losses. The response to abiotic stresses is a very complex phenomenon, since several stages of plant development can be affected by a particular stress and often several stresses affect the plant simultaneously. In order to mitigate the damages caused by the climate, new soybean cultivars adapted to the drought and the diversified climate are necessary, as well as technological advances in the production of soybeans that must advance with the increase of cultivated area. Therefore, the mechanisms underlying tolerance and adaptation to stress have been the focus of intensive research. In this sense, the objective of this review is to provide an overview of the evolution of genetic improvement regarding the search for more drought-tolerant cultivars, as well as to verify which strategies are used in the genetic improvement of soybean in the search of these genotypes.