Late-season nitrogen application increases grain protein concentration and is neutral for yield in wheat. A global meta-analysis

•Meta-analysis highlighted physiological drivers of wheat response to late N•Grain yield was unaffected by late N across a broad range of environments•Late N increased protein by 3.96% and its effects were heterogeneous•Protein increased linearly with the proportion of late N and with later applications•Higher protein response to late N associated to favourable growing conditions