## 3 Results and Discussion
### Variations of Biochemical Traits
#### 3.2.2 Antioxidant Activities  
Excess production of reactive nitrogen species (RNS) and reactive oxygen species (ROS) in the human body is the cause of many health ailments [7; 12; 57]. Dietary crops that have the property to scavenge these reactive radicals are very important and are of research focus [12]. In this study, the antioxidant activities of the barley accessions were determined using three in vitro radical scavenging assays, including DPPH\({}^{\bullet}\) scavenging activity, ABTS\({}^{\bullet+}\) scavenging activity, and reducing power (RP). Significant variation (\(p<0.05\)) was observed among the barley accessions, and their performance also significantly differedfrom that of the control cultivars (Tables 2 and S3). DPPH\({}^{\bullet}\) scavenging activity and RP were in the ranges of 1.56-6.24 and 1.31-7.86 mg AAE/g, respectively, the former showing a four-fold difference while the latter showing a six-fold difference. ABTS\({}^{\bullet+}\) scavenging activity was in the ranges of 3.07-13.54 mg AAE/100 g, showing an approximately four-fold variation. GRA2621, a barley accession from Greece, simultaneously displayed the highest DPPH\({}^{\bullet}\) scavenging activity, ABTS\({}^{\bullet+}\) scavenging activity, and RP. In contrast, accessions PI 477805 from Peru, CIho 4169 from Afghanistan, and CIho 3970-1 from Mongolia displayed the lowest ABTS\({}^{\bullet+}\) scavenging activity, DPPH\({}^{\bullet}\) scavenging activity, and RP, respectively. Several studies have evaluated the antioxidant activities of barley genetic materials. For instance, [PERSON] et al. [58] studied 20 barley genotypes and reported DPPH\({}^{\bullet}\) scavenging activity and ABTS\({}^{\bullet+}\) scavenging activity in the ranges of 8.20-13.40 and 10.51-15.60 \(\upmu\)mol Trolox equivalent per gram (\(\upmu\)mol TE/g), respectively. In another study, DPPH\({}^{\bullet}\) scavenging activity ranged from 9.33 to 11.78 \(\upmu\)mol TE/g, while ABTS\({}^{\bullet+}\) scavenging activity ranged from 11.39 to 13.58 \(\upmu\)mol TE/g [59]. [PERSON] et al. [60] also reported DPPH, ABTS, and RP in the ranges of 45.22-59.84, 43.22-64.35, and 22.55-77.58%, respectively. Apart from genotype and environmental effects, discrepancies in sample extraction protocols, assays, and reporting methods could cause such variations, as highlighted before [6; 61]. In the control cultivars, each of the DPPH\({}^{\bullet}\) scavenging activity and ABTS\({}^{\bullet+}\) scavenging activity decreased in the order of Betaone > Saechalssalbori > Heukdahyang > Saessalbori > Heuknuri.  
In the RP, however, Saessalbori and Heuknuri interchanged their orders, the remaining being similar to those observed for DPPH\({}^{\bullet}\) scavenging activity and ABTS\({}^{\bullet+}\) scavenging activity. A comparative analysis revealed that the majority of the barley accessions had much lower antioxidant activities than all the control cultivars. Specifically, a total of 245 accessions had lower ABTS, 299 accessions had lower DPPH, and 319 accessions had lower RP than all the control cultivars. Despite these observations, five accessions, including GRA2621 from Greece, GRA2256 from TJK, UZB-BHJ-2002-23-2 from Uzbekistan, PI 204875 from Turkey, and GRA1015 from Ukraine, displayed higher ABTS\({}^{\bullet+}\) scavenging activity than all the control cultivars. In contrast, only one accession, GRA2621, from Greece displayed higher DPPH\({}^{\bullet}\) scavenging activity. Once again, GRA2621 and GRA2256 from TJK were the two accessions that displayed higher RP than all the control cultivars (Table S4). Interestingly, all of these accessions simultaneously displayed a higher TPC level than all the control cultivars, and hence, they could be important sources of antioxidants [6; 12; 57].