Morphological and Physiological Traits that Explain Yield Response to Drought Stress in Miscanthus

Marta Malinowska,Paul Robson,Iain Donnison

doi:10.3390/agronomy10081194

Abstract

Miscanthus is a high yielding perennial grass capable of high biomass yields with low inputs. Traits associated with yield have been identified in miscanthus, but less is known about the traits associated with sustaining biomass production under drought stress. The commercial hybrid M. × giganteus and high yielding examples from the parental species M. sinensis and M. sacchariflorus were grown under well-watered and moderate drought conditions. Growth, morphology, physiology and phenotypic plasticity were analyzed. Functional data were parameterized and a matrix of traits examined for associations with yield, genotype and drought treatment. Phenotypic plasticity was determined, indexes were then calculated to determine the plasticity of trait responses. All genotypes assessed responded to moderate drought stress, and genotypic differences in yield decreased under drought. Genotypes with low tolerance exhibited greater plasticity than highly drought tolerant M. sinensis. In well-watered plants variance in yield was explained by a relatively simple empirical model including stem length and stem number, whereas under drought a more complex model was needed including the addition of leaf area and stomatal conductance data. This knowledge can help us to define ideotypes for drought tolerance and develop miscanthus varieties that sustain high yields across a range of environmental conditions.

Highlights

To produce sustainable biomass for the bioeconomy, crops are required, which can displace carbon-intensive feedstocks while limiting any potential negative impacts [1]
In this study we examined five high yielding and diverse miscanthus genotypes to determine how associations between yield and morphological and physiological traits changed between well-watered and drought conditions
In contrast to some previous studies [25] and in agreement with others [26] we showed the commercial type M. × giganteus (WAT09) had high water use, low water use efficiency and high stomatal conductance in control treatments but that stomata were responsive to drought

Summary

Introduction

To produce sustainable biomass for the bioeconomy, crops are required, which can displace carbon-intensive feedstocks while limiting any potential negative impacts [1]. Important characteristics of energy crops include high energy output to input ratios, a low requirement for agronomic interventions such as irrigation [2], an ability to grow on underutilized marginal land to minimize pressure on food production [3,4] and increasing opportunities for rural development and diversification [5]. It is, necessary to develop energy crops which exhibit high yields and resilience to environmental stresses. The ability of plants to withstand drought and efficiently produce biomass under moderate drought is important [10]

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Discussion

Conclusion