UC Davis

Malting barley (Hordeum vulgare L.) productivity and grain quality are of critical importance to the malting and brewing industry. In this study, we analyzed 12 malting barley genotypes across 8 locations in California and 3 years (2017–2018, 2018–2019, and 2020–2021). The effects of genotype (G), location (L), year (Y), and their interactions were assessed on grain yield (kg ha−1), grain protein content (%), individual-grain weight (mg), thousand kernel weight (TKW; g), grain size (plump and thin; %), onset gelatinization temperature (GT; temperature at which starch starts to gelatinize), peak GT, offset GT, difference between onset and peak GT, and difference between peak and offset GT. L, Y, and their interaction explained the largest variance for all traits except TKW, peak GT, and difference between onset and peak GT, for which G explained the largest variance. Yield and plump (%) were weakly negatively correlated with onset and peak GT (Pearson's r of −0.15 to −0.21) but showed a positive correlation with the difference between peak and offset GT (Pearson's r of 0.37 and 0.36). The 2020–2021 samples formed partially distinct clusters in principal component analysis, mainly discriminated by high percentage of thins and high onset GT. These findings illustrate the key roles of G, L, and Y in determining malting barley productivity and quality.