Evaluation of quinoa genotypes for their salinity tolerance at germination and seedling stages

Freshwater scarcity and salinity stress are major constraints for irrigated agriculture in the arid West Texas region. Alternative crops that are tolerant to salinity and less water-intensive are needed for long-term agricultural sustainability in this region. Quinoa (Chenopodium quinoa Willd.) is a halophytic crop with its seed having high market value and that can be a potential substitute for traditional crops. However, its salinity tolerance is a variable trait among genotypes and was shown to differ with growth stages. This study evaluated 25 quinoa genotypes that are suitable for growing in this arid region for their salinity tolerance at germination stage and classified them based on their stress tolerance index (STI). A completely randomized factorial design was used with water salinity and quinoa genotypes as two factors. Quinoa seeds were subjected to salinity stress at 1, 10, 15, 20, 25, and 30 dS m(-1), their germination determined for two weeks, and seedling growth was evaluated through biomass production. Results showed that germination decreased significantly (by 60%) across all genotypes as salinity increased, with zero germination at 30 dS m(-1). All genotypes differed significantly across salinity levels, with percent germination ranging between 37-72%. Using hierarchical cluster analysis, 23GR, 130R, 124R, and 31P were identified as highly salt-tolerant genotypes at seed germination. Seedling biomass also decreased with increasing salinity, but genotypical differences were not as pronounced as at the germination stage. We conclude that salinity tolerance at germination and seedling growth stages is indeed a variable trait among selected quinoa genotypes.