Comparative adaptive responses of quinoa cultivars grown hydroponically under saline-sodic stress

Pakistan has 22 million hectares (Mha) of cultivated land, of which 6.67 Mha are affected by salinity and sodicity, negatively impacting crop growth and quality. Quinoa, a facultative halophyte, was tested under hydroponic conditions to evaluate the effects of saline-sodic water on the growth, biomass, and ionic concentration of four quinoa cultivars (UAF-Q7, GLN-22, GLN-29, and GLN-33), and to assess their tolerance to salt stress. Five treatments were established: (i) control (no salt), and four saline-sodic irrigation waters with EC: SAR combinations of (ii) 10 dS m− 1:20 (mmol L− 1)1/2, (iii) 10 dS m− 1:40 (mmol L− 1)1/2, (iv) 20 dS m− 1:20 (mmol L− 1)1/2, and (v) 20 dS m− 1:40 (mmol L− 1)1/2. Seeds were germinated in a plant nursery, and uniform seedlings were transplanted to 25-L half-strength Hoagland’s nutritional solution. To prevent osmotic shock, salt stress was gradually applied one week after transplantation. Plant analysis showed that saline-sodic water negatively affected quinoa, particularly GLN-22. Among the tested cultivars, GLN-33 performed best at all EC: SAR levels, whereas GLN-33 and GLN-29 performed well at higher SAR levels. The GLN-22 cultivar showed sensitivity to all salt stress levels, as indicated by the increased accumulation of Na+ by 84% and 72% in the leaves and roots, respectively. Based on the results, it was concluded that GLN-33 tolerated all stress levels up to EC 20 dSm− 1 and SAR 40, with significantly better growth, lower Na+ accumulation (< 42% increase in leaves), and higher K+ retention compared to other cultivars. Thus, GLN-33 has the potential to grow efficiently in soils irrigated with saline water, owing to its effective defense system against salt stress. The performance of four different quinoa cultivars was studied under varying saline-sodic hydroponic culture. Saline-sodic conditions exhibited negative impacts on the growth and physiology of all quinoa cultivars, especially GLN-22. GLN-33 emerged as a remarkably salt-tolerant cultivar, showing resilience and robust growth. GLN-33 could be a promising choice for regions with poor soil quality and water resources