Effect of water stress and Pseudomonas sp. inoculation on seed yield and morphophysiological traits of quinoa genotypes from Bolivia

Abstract Climate change is expected to intensify drought frequency and variability, threatening agricultural productivity and food security, particularly in vulnerable regions such as the Andean highlands. Quinoa ( Chenopodium quinoa Willd.), a climate-resilient crop with high nutritional value, represents a promising alternative for sustainable food production under drought conditions. This study evaluated drought tolerance and plant growth-promoting rhizobacteria-mediated responses in nine Bolivian quinoa genotypes under growth chamber and greenhouse conditions. Plants were grown under well-watered (50% water-holding capacity) or water-deficient (25% water-holding capacity) conditions, with or without inoculation of Pseudomonas sp. strain IIFB019. ANOVA showed that genotype, water regime, and bacterial inoculation had significant effects on the phenotypic traits ( P < 0.05), with strong genotype-environment interactions observed at both flowering and maturity stages. Stress tolerance indices consistently identified Real Noventon and Real Negra as drought-tolerant genotypes, whereas Jacha Grano was drought-susceptible under non-inoculated conditions. Water deficit reduced plant growth, biomass, and grain yield, while chlorophyll content increased significantly under stress ( P < 0.05). Pseudomonas inoculation modified drought responses with genotypic specificity, improving chlorophyll content and root growth at flowering. Notably, bacterial inoculation shifted Jacha Grano from a sensitive to a more tolerant response based on stress susceptibility indices. These findings demonstrate substantial genotypic variation in drought tolerance and responsiveness to beneficial microorganisms in quinoa. Integrating drought-resilient genotypes with microbial inoculants may provide a promising strategy to enhance quinoa productivity and climate resilience.