Nutritional diversity in leaves of various amaranth (Amaranthus spp.) genotypes and its resilience to drought stress

Abstract

The nutritional diversity in leaves of twelve accessions of four amaranth species (Amaranthus caudatus, A. cruentus, A. hybridus, A. hypochondriacus) was studied in a randomized complete block design (n = 5). The accessions revealed high contents of the macronutrients K, Ca, Mg, and P, while the micronutrients Fe and Zn were comparatively low (542 – 717, 304 – 497, 131 – 230, 74 – 166, 0.9 – 1.3, 0.4 – 0.9 mg 100 g^-1 fresh weight, respectively). Protein contents were found to be higher (23 – 32%) compared to other commonly consumed leafy vegetables in Sub-Saharan-Africa. Phenolic acid and flavonoid contents strongly varied between accessions and to some extent were lower in comparison to those reported in literature. Amaranth is reported to be drought tolerant, thus, one accession of each species was subjected to two different drought stress conditions (moderate – 35 – 45% field capacity, severe – 15 – 25% field capacity, n = 3). Well-watered plants were used as control (60 – 70% field capacity). A significant reduction in plant height and fresh matter occurred in all accessions with increasing drought stress, whereas contents of nutritional compounds increased. Phenolic acids and flavonoid contents in all accessions/species were not affected by drought stress except for A. cruentus where total phenolic acids significantly increased