Melatonin priming as a promising approach to improve biomass accumulation and the nutritional values of Chenopodium quinoa sprouts: A genotype-based study

Increasing the production of horticultural crops is one of the most important challenges worldwide. Seed priming is a promising agricultural procedure for supporting growth and quality of economic crops. Among the most efficient seed priming agents that play a significant role in improving plant growth, chemical composition and bioactivity is melatonin (MT). This study was carried out to investigate the impact of MT priming on sprouting of three genotypes of quinoa (Chenopodium quinoa) and their nutritive value. Different primary and secondary metabolites of the three genotypes (regalona, kvl-sra2, Q37) were quantified. MT priming promoted the growth of quinoa genotypes by increasing their biomass accumulation and total nutrient content. Regarding the effect of MT priming on pigments, there was an obvious upward trend in leaf pigments of regalona. Besides, our results showed that MT priming increased the vitamins content such as thiamin and tocopherol content. Essential amino acids, organic acids and unsaturated fatty acids were significantly higher in MT-primed plants relative to the corresponding controls. Further, MT priming enhanced the accumulation of total soluble sugar, polyphenols, and flavonoids, which contribute to higher antioxidant and antidiabetic activities. Interestingly, species-specific responses toward MT priming were noticeable, where kvl-sra2 sprouts showed the highest antioxidant and antidiabetic activities among the three-quinoa genotypes. Overall, the current results suggest that MT priming could be used as a powerful agricultural approach to improve the growth and functional food value of quinoa sprouts.