Tolerance to saline conditions

Salinity is today one of the most widespread constraints in irrigated agriculture. Thus, salt tolerance is an agronomically important trait receiving increasing attention among scientists worldwide. Quinoa is tolerant to soil salinity and other adverse environmental factors, hence it attracts the attention of researchers as a possible crop in a changing world scenario in which scarcity of water resources and increasing soil and water salinization are the primary causes of crop loss. Quinoa’s exceptional tolerance to salinity, frost, drought and other types of abiotic stress also makes it a model species for investigating cellular, physiological, biomolecular and morphological mechanisms at the basis of stress tolerance in halophytes and in plants as a whole. There are quinoa ecotypes adapted to valley, highland, salt desert, sea level and tropical environments, displaying broad genetic variability in salinity tolerance. For this reason, quinoa represents a valuable resource for selection of the most suitable material and for breeding new varieties adapted to different environmental and geographical conditions. In this chapter, scientific studies on salinity tolerance in quinoa conducted in the last decade by numerous research groups operating in at least nine different countries are described. We focus on studies in which different quinoa genotypes are compared for their response to saline conditions, demonstrating that salt tolerance is a complex, multigenic trait involving a plethora of physiological and structural adaptations. Results available to date regarding the effect of salinity on the nutritional properties of quinoa are reported.