Functional Strategies and Life Histories of Grasses Underlying Yield and Resilience

Abstract

The family of Poaceae (grasses) includes many economically important crops. While grass grain crops (cereals) are typically annual, bioenergy and forage crops can have annual or perennial life histories. Annuals and perennials differ in important life history traits, such as the regulation of flowering and senescence, which determine to what extent resources are allocated to the grain, vegetative growth, or storage. These differences are also reflected in physiological characteristics; in particular, leaf traits that can be used to determine functional strategies (competitive, stress tolerant, or ruderal). While ruderality is associated with yield in annual grain crops, stress tolerance is usually higher in perennials. In this article, we discuss variation in functional strategies within perennial ryegrass grass ( Lolium perenne ) and species of the genus Brachypodium , demonstrating variation in characteristics for ruderality and stress tolerance. We argue that regulation of senescence of organs and whole plants determines these strategies and propose ideas on how functional strategies could potentially be optimised to increase grain yield in perennial grasses while maintaining stress resilience and other beneficial traits associated with perenniality.

Relationships of the competitor, stress tolerator, ruderal functional strategies of grass species with lifespan, photosynthetic type, naturalization and climate

“…Recently, Yu et al (2022) used the StrateFy tool for alpine Tibetan grasslands, demonstrating that stress tolerator strategies dominated. Using the same method, intrageneric and intraspecific variation was found for the grass genus Brachypodium , showing variation along the S and R axes in perennial Brachypodium species, while the annual model species B. distachyon was classified to have a less competitive strategy ( Crowley and Wingler 2020 ). Intraspecific variation in functional strategies was also described for perennial ryegrass ( Lolium perenne ), demonstrating a trade-off between growth and dehydration survival ( Keep et al 2021 ).…”

“…Intraspecific variation in functional strategies was also described for perennial ryegrass ( Lolium perenne ), demonstrating a trade-off between growth and dehydration survival ( Keep et al 2021 ). Such variation is reflected in CSR classification, which showed that perennial ryegrass has a mainly ruderal strategy, but with variation along the S- and R-axes ( Crowley and Wingler 2020 ).…”