Increased yield stability of field-grown winter barley (Hordeum vulgare L.) varietal mixtures through ecological processes

Henry E Creissen,Tove H Jorgensen,James K.M Brown

doi:10.1016/j.cropro.2016.03.001

Henry E Creissen, Tove H Jorgensen + Show 1 more

Open Access

https://doi.org/10.1016/j.cropro.2016.03.001

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Journal: Crop Protection	Publication Date: Mar 25, 2016
Citations: 59	License type: cc-by

Affiliation: University of East Anglia, Aarhus University

Abstract

Crop variety mixtures have the potential to increase yield stability in highly variable and unpredictable environments, yet knowledge of the specific mechanisms underlying enhanced yield stability has been limited. Ecological processes in genetically diverse crops were investigated by conducting field trials with winter barley varieties (Hordeum vulgare), grown as monocultures or as three-way mixtures in fungicide treated and untreated plots at three sites. Mixtures achieved yields comparable to the best performing monocultures whilst enhancing yield stability despite being subject to multiple predicted and unpredicted abiotic and biotic stresses including brown rust (Puccinia hordei) and lodging. There was compensation through competitive release because the most competitive variety overyielded in mixtures thereby compensating for less competitive varieties. Facilitation was also identified as an important ecological process within mixtures by reducing lodging. This study indicates that crop varietal mixtures have the capacity to stabilise productivity even when environmental conditions and stresses are not predicted in advance. Varietal mixtures provide a means of increasing crop genetic diversity without the need for extensive breeding efforts. They may confer enhanced resilience to environmental stresses and thus be a desirable component of future cropping systems for sustainable arable farming.

Highlights

An alternative to the variety monoculture system is the use of varietal mixtures in which several genotypes are sown together in the same field to buffer against environmental stresses, including disease, and to increase yield stability (Wolfe, 1985; Lannou and Mundt, 1996; Zhu et al, 2000)
This study investigated how ecological processes act to buffer against environmental stresses and stabilise yield in barley variety mixtures
Varietal mixtures enhanced spatial yield stability compared to the mean of the component monocultures, supporting the hypothesis that biodiversity increases ecological stability i.e. the ability of an ecological system to maintain or quickly regain productivity despite diverse environmental stresses (Tilman, 1996; Yachi and Loreau, 1999)

Summary

Introduction

An alternative to the variety monoculture system is the use of varietal mixtures in which several genotypes are sown together in the same field to buffer against environmental stresses, including disease, and to increase yield stability (Wolfe, 1985; Lannou and Mundt, 1996; Zhu et al, 2000). The theory underpinning the use of mixtures is largely based on the hypothesis that biodiversity increases ecological stability (Yachi and Loreau, 1999). This approach relies on beneficial ecological processes to increase the system's potential to buffer against adverse environmental conditions, reduce fertiliser inputs and control disease (Finckh and Wolfe, 1998). When weaker individuals are harmed by environmental stress, stronger plants can increase their yields through compensation via competitive release (a reduction in competition) (Tilman, 1996; Creissen et al, 2013, 2015)

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