Quinoa growth and yield performance under salinity stress in arid West Texas

Crops such as quinoa (Chenopodium quinoa Willd.) that are both salinity and drought-tolerant and with high seed value are needed to sustain agriculture in arid Far West Texas facing dual threat of freshwater scarcity and soil salinization. However, quinoa's growth and yield performance under arid conditions of Far West Texas has not been studied previously. This study evaluated growth and yield of a salt-tolerant quinoa genotype under greenhouse conditions using a completely randomized experimental design with irrigation water salinity as the main factor having five different levels (freshwater, 5, 10, 15, and 20 dS m⁻¹). Plant parameters (plant height, leaf SPAD, leaf tissue carbon, and nitrogen concentrations) and seed yield were measured for two growing seasons. Soil quality (salinity and sodicity) changes were also determined for the same time. Seed yields ranged between 747 and 6065 kg ha⁻¹ across 2 years, indicating significant effects of water salinity. However, these yields were comparable to those reported in the literature. Increasing water salinity significantly affected all growth parameters with leaf C and N decreasing by an average of 20%, whereas reductions in plant height reached a high of 60% at 20 dS m⁻¹. Similar reductions in leaf chlorophyll content were found with increasing water salinity. Soil salinity and sodicity significantly increased over time with irrigation water salinity. Importantly, we observed that quinoa has a much higher soil salinity threshold (∼12 dS m⁻¹) above which yields declined rapidly. Higher salt tolerance threshold of quinoa makes it an alternative economically viable crop for the Trans-Pecos Texas region.