## 3 Results and Discussion
### Variations of Biochemical Traits  
#### 3.2.1 \(\beta\)-Glucan and Total Phenolic Contents  
Studies showed that \(\beta\)-glucan and phenolic compounds in barley have synergistic roles as antioxidants to prevent various ailments. Therefore, they are one of the determinant factors in the selection of quality barley genotypes [50]. In this study, the \(\beta\)-glucan content in the entire population ranged from 0.14 to 8.41 g/100 g, showing a sixty-fold variation (Tables 2 and S3). Betaone, one of the control cultivars, showed the maximum \(\beta\)-glucan content, while Castelar-668 from Argentina had the lowest (\(p<0.05\)). Previously, \(\beta\)-glucan content in the ranges of 2.40-7.42 g/100 g was reported across barley genotypes grown in the Czech Republic and Spain [23], while [PERSON] et al. [24] reported 4.20-8.94% across barley genotypes grown at three different locations in the USA, both being close to the ranges observed in our study. In another study, a much narrower range of \(\beta\)-glucan content (2.5-4.6%) was reported in barley-inbred lines grown in Italy [51]. Like in the agronomical traits, both environmental and genetic factors contribute to the variations observed in biochemical traits in barley, resulting in such wide-ranging values [52]. A comparative analysis of the barley accessions to the control cultivars revealed that none of the barley accessions had a higher \(\beta\)-glucan content than Betaone. Overall, the average \(\beta\)-glucan content was significantly higher in the control cultivars. Although the majority of the barley accessions (\(n=203\)) displayed a lower \(\beta\)-glucan content than all the control cultivars, 79 accessions had a higher \(\beta\)-glucan content than all the control cultivars except Betaone. In particular, accessions PI235639 from Germany and IG38956 from Israel displayed \(\beta\)-glucan levels (7.67 and 7.08%, respectively) close to that of Betaone and, hence, could be good sources of \(\beta\)-glucan [53].  
The TPC was also in the range of 1.79-6.97 mg GAE/g, showing an approximately four-fold variation (Tables 2 and S3). The highest TPC was found in accession K222037-2 from Turkey, while the lowest TPC was found in accession GAW 72-11 from Ethiopia. Several studies have examined the TPC levels of different barley genotypes along with their antioxidant activities. However, differences in cultivation conditions, use of biostimulants, and experimental parameters influence the levels of these biochemical traits, resulting in wide differences in the reported values [39; 40; 54]. For instance, a TPC ranging from 333.9 to 460.8 mg GAE/100 g was reported across four Chinese barley varieties [39]. Likewise, TPC ranged from 1929.0 to 2917.0 ug GAE/g in [PERSON] et al.'s [51] study, which was comparable to the result obtained in our study. In contrast, a much narrower TPC range (195.02-220.11 mg GAE/100 g) compared to our findings was reported across four barley cultivars grown in Tunisia [55]. Among the control cultivars, Betaone once again displayed the highest TPC (4.00 mg GAE/g), while Saessalbori displayed the lowest (2.91 mg GAE/g). A total of 20 accessions displayed a higher TPC compared to all the controls, including Betaone, while 194 accessions had a lower TPC. As highlighted before, \(\beta\)-glucan and phenolic compounds play significant roles in disease prevention and health promotion. Moreover, the development of barley varieties with maximized levels of these metabolites is one of the research focuses [12; 53; 56; 57]. Accordingly, those accessions that displayed higher levels of TPC and \(\beta\)-glucan content could be important genetic materials (Table S4).