Functional Flavonoid Profiling and Combining Ability in Barley under Normal Conditions

Abstract

This study investigated the genetic architecture of functional flavonoid components in barley using a Line x Tester mating design under normal growing conditions. We evaluated 23 genotypes, comprising five lines, three testers, and 15 F-1 hybrids, for key functional compounds: catechin, myricetin, quercetin, kaempferol, and total flavonoids, quantified via High-Performance Liquid Chromatography (HPLC). Analysis of variance (ANOVA) revealed highly significant genetic variability (p <= 0.01) among genotypes for all traits, indicating strong potential for genetic improvement. Both additive and non-additive gene actions significantly influenced flavonoid expression, with line x tester interactions being highly significant for all traits, underscoring the importance of specific combining ability (SCA). Parental genotype L4 consistently showed superior mean performance and highly significant positive General Combining Ability (GCA) effects across all traits, including catechin (0.072), quercetin (0.101), kaempferol (0.090), and total flavonoids (0.213), identifying it as the best general combiner. Tester T1 also demonstrated significant positive GCA effects, notably for total flavonoids (0.095) and kaempferol (0.062). Among hybrids, L4xT1 exhibited the highest mean values for catechin (1.51 mg/g DW), quercetin (1.18 mg/g DW), kaempferol (0.96 mg/g DW), and total flavonoids (4.58 mg/g DW), accompanied by strong positive SCA effects (e.g., kaempferol: 0.100, total flavonoids: 0.105), indicating favorable dominance and epistatic interactions. Dominance variance (sigma D-2) consistently exceeded additive variance (sigma(2)A) for all traits. Broad-sense heritability (H2) was moderately high, ranging from 0.71 (quercetin) to 0.73 (total flavonoids), suggesting effective selection is feasible. These findings emphasize that hybrid breeding strategies effectively exploit both additive and non-additive gene actions for developing nutritionally enhanced barley cultivars.