Physiological and biochemical responses of a wide range of quinoa accessions to accelerated ageing conditions

Quinoa is known as a nutrient-enriched and climate-resilient crop, but its seed longevity is challenging for seed enterprises, farmers and germplasm preservation. In this study, 291 quinoa accessions were exposed to 30 or 60% relative humidity (RH) and then stored at ambient and high temperature (50°C) environments for three months. Of seeds equilibrated at 60% RH and stored at 50°C, only 120 accessions survived with 50% germination after 15 days, but these accessions completely lost their germination after one month. The accessions exposed to low RH (30%), maintained germination within the range of 50-100%, which decreased to 40 and 25% after 45 and 60 days, respectively. After 90 days, only 25 accessions maintained their germination above 98% at low RH. The quinoa accessions stored after equilibration at 30% RH also retained the seed crude protein, α-amylase activity and total soluble sugars, while high RH and temperature accelerated seed malondialdehyde contents, electrolyte leakage and reduced antioxidant activities, resulting in either decrease or completely loss in seed viability. Five quinoa accessions maintained seed viability due to better membrane integrity and antioxidant defense system.