Abstract
Drought stress significantly impacts crop productivity, yet its influence on genomic and epigenetic variation in quinoa remains poorly understood. This study aimed to assess DNA damage and cytosine methylation alterations in six quinoa genotypes (Titicaca, Rainbow, Moqu Arrochilla, Cherry Vanilla, China, and White) exposed to five irrigation levels (5%, 10%, 25%, 50%, and 100% field capacity). Genomic changes were evaluated using inter-primer binding site (iPBS) markers, while DNA methylation was analyzed via CRED-iPBS. Results revealed genotype-specific polymorphism and genomic template stability (GTS) responses to irrigation stress. Moqu Arrochilla showed the highest GTS (84.6%) under 5% field capacity, while White exhibited the lowest (35.0%) at 50% field capacity. CRED-iPBS analysis indicated both hyper- and hypomethylation events depending on stress intensity, with China and Moqu Arrochilla genotypes displaying the highest polymorphism rates for MspI (42.9%) and HpaII (39.0%), respectively. These findings highlight the drought-induced genomic and epigenetic variability in quinoa, emphasizing the utility of iPBS and CRED-iPBS techniques for screening stress-responsive genotypes. This work contributes to the understanding of stress adaptation and may inform breeding programs targeting drought tolerance.