Evaluation of wild barley introgression lines for agronomic traits related to nitrogen fertilization

In the coming decades, climate change and resources constraints will make profitable and economically reliable agriculture more and more challenging. To evaluate the potential of exotic alleles to maintain performance under low nitrogen input, we investigated a set of 41 introgression lines (S42ILs) originating from the hybridization of the German spring barley ‘Scarlett’ and the Israeli wild barley ‘ISR42-8’. These lines were assessed in field trials for yield, yield components, grain protein content and chlorophyll content during growing seasons 2015 and 2016 in two different test sites in Germany under low and high nitrogen supply levels, N0 and N1. Our analyses revealed 17 regions for putative quantitative trait loci (QTL), linked to one or multiple traits, across all chromosomes. In particular, lines S42IL_119 and S42IL_121 exhibited an enhanced thousand grain weight of 7% and 9% under N1 and N0, respectively. In addition, six QTL were found for grain number per ear leading to a decline of grain number of up to 20%. Furthermore, three new QTL for chlorophyll content could be identified on chromosomes 1H and 2H. The present study revealed QTL effects of wild barley introgressions in a spring barley elite background, especially under low nitrogen. The selection for nitrogen efficient lines with beneficial exotic alleles represents the first step towards the development of spring barley cultivars genetically adapted to nitrogen limitations.