Gas exchange-yield relationships of malting barley genotypes treated with fungicides and biostimulants

•Leaf gas exchange traits correlated with grain yield in unfavorable year only.•The length of pre-heading period correlated positively with grain yield.•Larger grain number, weight and WUE were associated with higher grain yield.•Larger number of ears per area resulted in lower grain yield.•Fungal pathogens shortened grain filling period and reduced grain yield.