Genotypic and Environmental Influences on Grain, Malt and Wort Quality Traits of Barley under Subtropical Conditions: Implications for Climate-Resilient Malting Barley Breeding

Genotypic and Environmental Influences on Grain, Malt and Wort Quality Traits of Barley

Abstract

Malting quality in barley is governed by complex genotype × environment interactions that influence grain, malt and wort characteristics. Fourteen barley (Hordeum vulgare L.) genotypes comprising seven indigenous and seven exotic cultivars were evaluated during two crop seasons (2020–21 and 2021–22) under subtropical conditions of north-western India to assess variability in grain, malt and wort quality traits. Significant (P ≤ 0.05) genotypic variation was observed for test weight (57.3–66.3 kg hl–¹), thousand grain weight (35.2–57.1 g), bold grain percentage (38.3–92.0%), grain β-amylase activity (11.0–27.4 BAU g–¹) and grain β-glucan content (3.6–6.1%). The favourable 2020–21 season recorded significantly higher test weight (64.9 vs. 60.2 kg hl–¹), thousand grain weight (46.4 vs. 39.1 g), bold grains (78.8 vs. 51.4%) and malt β-amylase activity (16.1 vs. 7.5 BAU g–¹) than the warmer 2021–22 season, whereas grain protein content increased from 12.4 to 14.3%. Indigenous cultivars exhibited superior grain physical traits, with higher test weight (64.5 vs. 60.6 kg hl–¹), thousand grain weight (47.7 vs. 37.8 g) and bold grains (76.3 vs. 53.9%), while exotic cultivars possessed significantly higher grain β-amylase activity (22.3 vs. 15.3 BAU g–¹), malt α-amylase activity (224.0 vs. 157.4 CU g–¹), diastatic power (96.6 vs. 83.4 °Lintner), hot water extract (79.0 vs. 77.0%) and lower grain β-glucan content (4.1 vs. 5.2%). Wort β-glucan content ranged from 329.3 to 1139.1 mg L–¹ among genotypes. DWRB 91 and DWRB 160 combined superior grain physical characteristics with adaptation to subtropical conditions, whereas Traveller and Andreia exhibited superior malting quality attributes. The study demonstrates the strong influence of seasonal environment on malting quality under subtropical conditions and identifies complementary indigenous and exotic germplasm for developing climate-resilient malting barley cultivars.