Differential Flavonoid Accumulation and Drought Response among Barley Genotypes

Abstract

This study evaluated flavonoid composition and inter-trait relationships in twelve barley (Hordeum vulgare L.) genotypes under normal (T-1) and drought (T-2) conditions using a randomized complete block design (RCBD) with three replications in Yunnan, China. High-performance liquid chromatography (HPLC) quantified five key flavonoids: catechin, myricetin, quercetin, kaempferol, and total flavonoids. Significant genotypic variation was observed for all traits (p<0.05), with stronger expression under drought. Catechin ranged from 2.66 to 6.28 mg/g, peaking in genotype G3 under T-2, while total flavonoids (TFC) remained stable (T-1: 31.95 mg/g; T-2: 31.86 mg/g), with G3 reaching 37.51 mg/g under stress. Correlation analysis revealed strong positive associations among flavonoids (r = 0.81-0.96), particularly under drought, indicating a coordinated antioxidant response. Biplot explained 95.50% (T-1) and 96.08% (T-2) of total variance, effectively distinguishing high-performing genotypes. Biplot analysis identified G3, G5, and G11 as consistently superior in flavonoid accumulation, while G2, G4, and G9 showed poor performance. Genotype x treatment interaction was highly significant, reflecting genotype-specific metabolic shifts under drought. The intensification of trait correlations and stability of elite lines under stress highlight their utility for biofortification and climate-resilient breeding. These findings support flavonoid-based selection strategies for enhancing both nutritional quality and stress tolerance in barley breeding programs targeting functional food and arid-environment adaptation.