Abstract
Since the dawn of agriculture, crop yield has always been impaired through abiotic stresses. In a field trial across five locations worldwide, we tested three abiotic stresses, nitrogen deficiency, drought and salinity, using HEB-YIELD, a selected subset of the wild barley nested association mapping population HEB-25. We show that barley flowering time genes Ppd-H1, Sdw1, Vrn-H1 and Vrn-H3 exert pleiotropic effects on plant development and grain yield. Under field conditions, these effects are strongly influenced by environmental cues like day length and temperature. For example, in Al-Karak, Jordan, the day length-sensitive wild barley allele of Ppd-H1 was associated with an increase of grain yield by up to 30% compared to the insensitive elite barley allele. The observed yield increase is accompanied by pleiotropic effects of Ppd-H1 resulting in shorter life cycle, extended grain filling period and increased grain size. Our study indicates that the adequate timing of plant development is crucial to maximize yield formation under harsh environmental conditions. We provide evidence that wild barley alleles, introgressed into elite barley cultivars, can be utilized to support grain yield formation. The presented knowledge may be transferred to related crop species like wheat and rice securing the rising global food demand for cereals.
This work was financially supported by the German Research Foundation (DFG) via the priority program 1530: ‘Flowering time control - from natural variation to crop improvement’ with grants Pi339/7-1 and Pi339/7-2) and via ERA-NET for Coordinating Action in Plant Sciences (ERA-CAPS) grant Pi339/8-1. Funding from King Abdullah University of Science and Technology (KAUST) is also gratefully acknowledged. We are grateful to a multitude of research assistants, located at the James Hutton Institute in Dundee, the Martin Luther University in Halle, the International Center for Agricultural Research in the Dry Areas and NCARE in Al-Karak, the International Center for Biosaline Agriculture in Dubai and at the University of Adelaide for their excellent technical support in conducting the global field trials. We are grateful to Drs. Micha Bayer and Joanne Russell, The James Hutton Institute, Dundee, UK, providing exome capture-based SNP data of Ppd-H1, Ppd-H2, sdw1 and Vrn-H1, collected through the WHEALBI consortium (https://www.whealbi.eu/).