Matching source and sink: An environmentally tailored fungal endophyte consortium increases yield in three field-grown barley cultivars

Abstract

Environmental stresses are limiting factors in optimal agricultural crop yield, and these stresses, especially drought, are likely to become more acute due to future climate change. Crop wild relatives contain environmentally selected endophytes that can help to increase stress resistance. Our previous work with barley cultivars has shown a positive correlation between endophyte-induced yield increase and increasingly dry conditions. For this study, we hypothesised that a consortium of fungal endophytes recovered from a crop wild relative of barley growing in drought-stressed sites would enhance barley yield in similarly low moisture agricultural sites. We grew three barley cultivars on two environmentally distinct sites under three nitrogen (N) input regimes. We found that the endophyte inoculant induced an increase in grain dry weight at both sites, which experienced abnormally low local rainfall in the early growing season. The yield increase was 1.2 t/ha for standard N input, 1.1 t/ha for half N input and 0.6 t/ha with no N input. Additionally, on both sites, endophyte treatment with half N input recovered yield to that associated with untreated crops with standard N input for all three cultivars. Furthermore, the endophytes still retained their efficacy with regular foliar fungicidal crop treatments. These results show that endophytes recovered from sites with low and similar water status to the targeted barley growing sites can produce large and significant increases in yield regardless of nitrogen input, and hold promise for application in drought-stressed sites with limited access to expensive nitrogen fertilisers.