Effects of Genotype and Environment on Productivity and Quality in
Californian Malting Barley
Abstract
Malting barley productivity and grain quality are of critical importance
to the malting and brewing industry. In this study, we analyzed two
experiments: a multi-environment variety trial and a nitrogen management
trial. In the first experiment, we analyzed 12 malting barley genotypes
across eight locations in California and three years (2017-18, 2018-19
and 2020-21). The effects of genotype (G), location (L), year (Y) and
their interactions were assessed on grain yield (kg ha-1), grain protein
content (GPC; %), individual-grain weight, grain size (plump and thin;
%), onset gelatinization temperature (GT), 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 peak GT and difference between onset and peak GT, for
which G explained the largest variance. The 2020-21 samples formed
partially distinct clusters in principal component analysis, mainly
discriminated by high percentage of thin grains and high onset GT. In
the second experiment, we analyzed a dataset with two genotypes across
three locations (with varying nitrogen fertilizer levels) from the
2016-17 season to assess the effect of added nitrogen on the same
traits. Added nitrogen at tillering explained 18% of variance in the
difference between onset and peak GT, and 5% of the variance in GPC,
but was minimal for all other traits, with the largest variance
explained by location and genotype. These findings illustrate the key
roles of G, L and Y in determining malting barley productivity and
quality.