Tolerance of Lowland Quinoa Cultivars to Sodium Chloride and Sodium Sulfate Salinity

As soil salinization becomes a more urgent threat to global agriculture, halophytic crops such as quinoa ( Chenopodium quinoa Willd.) may provide a route of adaptation to these marginal soil conditions. Until recently, little research had been conducted on the levels of salinity tolerance of Chilean lowland cultivars, which are best adapted to temperate latitudes and high temperatures characteristic of many saline‐affected regions. In this study, Chilean lowland cultivars Baer, UDEC‐1, QQ065, and CO407D and the salt‐tolerant barley ( Hordeum vulgare L.) cultivar Albacete were exposed to a no‐salt control and to 8, 16, and 32 dS m −1 each of NaCl and Na 2 SO 4 for a total of seven salinity treatments. Plants were provided with two fertilizer treatments, high (3 g N, 0.86 g P, 0.86 g K per pot) and low (1 g N, 0.29 g P, 0.29 g K per pot). Yield, plant height, and leaf greenness were measured. At 32 dS m −1 , quinoa exhibited greater tolerance to Na 2 SO 4 applications than to NaCl. Quinoa showed greater saline tolerance than barley in percent yield decline under 32 dS m −1 NaCl and for three of four quinoa cultivars under 32 dS m −1 Na 2 SO 4 . Substantial variation was found in salinity tolerance among the quinoa cultivars. Yield declines of quinoa cultivars at 32 dS m −1 compared with the no‐salt control ranged from 43.8 to 73.7% under NaCl and from 10.8 to 51.9% under Na 2 SO 4 . High fertilization had a toxic effect on yield except for cultivar UDEC‐1, which increased in yield under the high fertility treatment.