Barley yield formation under abiotic stress depends on the interplay between flowering time genes and environmental cues

Mathias Wiegmann,Michael Baum,Jason Eglinton,Andreas Maurer,Klaus Pillen,Anh Pham,William T B Thomas,Ayed Al-Abdallat,Mohammed Shahid,Mark Tester,Andrew J Flavell,Timothy J March,Hazel J Bull

doi:10.1038/s41598-019-42673-1

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.

Highlights

One of the major challenges that mankind faces is the ability to feed the ever-growing population, especially in the face of increased stresses due to climate change and reduced availability of arable land[1,2]
We studied eleven agronomically traits in a HEBYIELD trial conducted in Dundee, Halle, Al-Karak, Dubai and Adelaide (Fig. 1; Supplementary Table S2a), where climate data for day length, temperature and precipitation varied considerably between locations Supplementary Figs S1 and S2)
Based on our findings we suggest that plant development in the wild barley population HEB-YIELD is mainly determined by genetic factors and to a lesser extend modified by abiotic stresses

Summary

Introduction

One of the major challenges that mankind faces is the ability to feed the ever-growing population, especially in the face of increased stresses due to climate change and reduced availability of arable land[1,2]. Barley is mainly used for animal feed and for malt production in large parts of the world It represents the fourth most important cereal crop on a global scale[5,6]. Wild barely may be an appropriate source to replenish the barley gene pool with novel genetic variation This variation may be valuable to cope with the challenges arising from climate change[26]. Grain yield depends on developmental phases of a plant’s life cycle[27] In this regard, flowering time is a key event as plants shift from vegetative to reproductive growth, moving towards providing the harvestable yield[28,29,30]. We investigated the role of known flowering time genes on developmental and yield-related traits, as well as how they account for yield and stress tolerance

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