This study details the breeding of a malting barley cultivar with enhanced acid soil tolerance. A 1-kb transposon, known to regulate the expression of the *HvAACT1* gene (involved in aluminum detoxification), was introgressed from the Murasakimochi cultivar into the elite malting cultivar Haruna Nijo via multiple backcrossing and marker-assisted selection. The resulting line, Haruna Nijo-AT, exhibited increased *HvAACT1* expression, enhanced citrate secretion, reduced aluminum binding to roots, and a two-to-threefold increase in grain yield on acidic soil compared to the original cultivar.

Sheng Huang, Kazuhiro Sato, Jian Feng Ma