Résumé
Crop domestication has led to the development of distinct trait syndromes,
a series of constrained plant trait trade-offs to maximize yield in
high-input agricultural environments, and potentially constrained trait
plasticity. Yet, with the ongoing transition to organic and diversified
agroecosystems, which create more heterogeneous nutrient availability,
this constrained plasticity, especially in root functional traits, may be
undesirable for nutrient acquisition. Such agricultural systems require a
nuanced understanding of the soil-crop continuum under organic amendments
and with intercropping, and the role crop genetic resources play in
governing nutrient management and design. In this study, we use a
functional traits lens to determine if crops with a range of domestication
histories express different functional trait plasticity and how this
expression changes with soil amendments and intercropping. We utilize a
common garden experiment including five wheat (Triticum aestivum)
varietals with a range of domestication histories planted in a factorial
combination with amendment type (organic and inorganic) and cropping
design (monoculture or intercropped with soybean). We use bivariate,
multivariate and trait space analyses to quantify trait variation and
plasticity in five leaf and five root functional traits. Almost all leaf
and root traits varied among varieties. Yet, amendment type was nearly
inconsequential for explaining trait expression across varieties. However,
intercropping was linked to significant differences in root acquisitive
strategies, regardless of the varietals’ distinct history. Our findings
show substantial leaf and root trait plasticity, with roots expressing
greater trait space occupation with domestication, but also the strong
role of management in crop trait expression. We underscore the utility of
a functional trait-based approach to understand plant-soil dynamics with
organic amendments, as well as the role of crop genetic histories in the
successful transition to low-input and diversified agroecosystems.