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Summary: Crops generally have seeds larger than their wild progenitors´ and with reduced dormancy. In wild plants, seed mass and allocation to the seed coat (a proxy for physical dormancy) scale allometrically so that larger seeds tend to allocate less to the coats. Larger seeds and lightweight coats might thus have evolved as correlated traits in crops.We tested whether 34 crops and 22 of their wild progenitors fit the allometry described in the literature, which would indicate co‐selection of both traits during crop evolution. Deviations from the allometry would suggest that other evolutionary processes contribute to explain the emergence of larger, lightweight‐coated seeds in crops.Crops fitted the scaling slope but deviated from its intercept in a consistent way: Seed coats of crops were lighter than expected by their seed size. The wild progenitors of crops displayed the same trend, indicating that deviations cannot be solely attributed to artificial selection during or after domestication.The evolution of seeds with small coats in crops likely resulted from a combination of various pressures, including the selection of wild progenitors with coats smaller than other wild plants, further decreases during early evolution under cultivation, and indirect selection due to the seed coat‐seed size allometry. [ABSTRACT FROM AUTHOR]

Summary: Growth rates vary widely among plants with different strategies. For crops, evolution under predictable and high‐resource environments might favour rapid resource acquisition and growth, but whether this strategy has consistently evolved during domestication and improvement remains unclear.Here we report a comprehensive study of the evolution of growth rates based on comparisons among wild, landrace, and improved accessions of 19 herbaceous crops grown under common conditions. We also examined the underlying growth components and the influence of crop origin and history on growth evolution.Domestication and improvement did not affect growth consistently, that is growth rates increased or decreased or remained unchanged in different crops. Crops selected for fruits increased the physiological component of growth (net assimilation rate), whereas leaf and seed crops showed larger domestication effects on morphology (leaf mass ratio and specific leaf area). Moreover, climate and phylogeny contributed to explaining the effects of domestication and changes in growth.Crop‐specific responses to domestication and improvement suggest that selection for high yield has not consistently changed growth rates. The trade‐offs between morpho‐physiological traits and the distinct origins and histories of crops accounted for the variability in growth changes. These findings have far‐reaching implications for our understanding of crop performance and adaptation. [ABSTRACT FROM AUTHOR]

Crop yields, i.e. harvestable production per unit of cropland area, are in decline for a number of crops and regions, but the drivers of this process are poorly known. Global decreases in pollinator abundance and diversity have been proposed as a major driver of yield declines in crops that depend on animals, mostly bees, to produce fruits and seeds. Alternatively, widespread tree mortality has been directly and indirectly related to global climate change, which could also explain yield decreases in tree crops. As tree crops are expected to be more dependent on pollinators than other crop types, disentangling the relative influence of growth form and pollinator dependence is relevant to identify the ultimate factors driving yield declines. Yield decline, defined here as a negative average annual yearly change in yield from 1961 to 2020, was measured in 4270 time series, involving 136 crops and 163 countries and territories. About one‑fourth of all time series showed declines in crop yield, a characteristic associated with both high pollinator dependence and a tree growth form. Because pollinator dependence and plant growth form were partially correlated, we disentangled the effect of each of these two predictors using a series of generalized linear mixed models that evaluated direct and indirect associations. Our analyses revealed a stronger association of yield decline with growth form than with pollinator dependence, a relationship that persisted after partialling out the effect of pollinator dependence. In particular, yield declines were more common among tree than herbaceous and shrub crops in all major regions but in Africa, a continent showing a high incidence of yield declines irrespective of growth form. These results suggest that pollinator decline is not the main reason behind crop productivity loss, but that other factors such as climate change could be already affecting crop yield.

Agricultural fields are commonly characterized by high nutrient and water availabilities, which are favourable for plant growth. Such conditions might promote the evolution of resource‐acquisitive strategies. We asked whether crop plants show root traits typical of resource‐acquisitive strategies and whether this strategy is primarily a result of their evolution under domestication or of the early selection of successful candidates for domestication.We studied a set of 30 crop species and their wild progenitors. We set up a greenhouse experiment to measure five root traits: root thickness, root tissue density, specific root length (SRL), root mass fraction (RMF) and root length ratio. In addition, we compiled data from other wild herbaceous species, growth in similar conditions to this experiment, to place the root traits of our crops in the context of wider botanical variation.Wild progenitors had thicker and less dense roots, with higher RMF and lower SRL, than other wild herbs. Thicker and less dense roots are indicative of fertile soils, which suggest that wild progenitors could have been adapted for success in agricultural conditions. Additionally, we found that domestication generally increased total plant dry mass, but none of the root traits evolved consistently towards a more resource‐acquisitive strategy after domestication across all species. Root trait values differed between progenitors and crop species for most pairs surveyed, but this occurred in diverse directions depending on crop species. Such differences were independent of phylogeny, functional group or variability in the domestication processes, such as timing of the domestication event or organ under focal artificial selection.Our comparative study revealed that the root phenotype exhibited by wild progenitors (thick roots with low density and SRL), when compared with other wild herbs, was in accordance with plants typical of fertile habitats. However, none of the root traits reacted to domestication in accordance with evolution towards faster growth strategies. Thus, the adaptation of crop root phenotypes to the fertile conditions of agricultural fields might be largely determined by early choices of wild species, rather than by further evolution under domestication. A plain language summary is available for this article. Plain Language Summary [ABSTRACT FROM AUTHOR]

Summary: The arbuscular mycorrhizal (AM) symbiosis is key to plant nutrition, and hence is potentially key in sustainable agriculture. Fertilization and other agricultural practices reduce soil AM fungi and root colonization. Such conditions might promote the evolution of low mycorrhizal responsive crops. Therefore, we ask if and how evolution under domestication has altered AM symbioses of crops. We measured the effect of domestication on mycorrhizal responsiveness across 27 crop species and their wild progenitors. Additionally, in a subset of 14 crops, we tested if domestication effects differed under contrasting phosphorus (P) availabilities. The response of AM symbiosis to domestication varied with P availability. On average, wild progenitors benefited from the AM symbiosis irrespective of P availability, while domesticated crops only profited under P‐limited conditions. Magnitudes and directions of response were diverse among the 27 crops, and were unrelated to phylogenetic affinities or to the coordinated evolution with fine root traits. Our results indicate disruptions in the efficiency of the AM symbiosis linked to domestication. Under high fertilization, domestication could have altered the regulation of resource trafficking between AM fungi and associated plant hosts. Provided that crops are commonly raised under high fertilization, this result has important implications for sustainable agriculture. [ABSTRACT FROM AUTHOR]

Vascular plant responses to experimental enrichment with atmospheric carbon dioxide (CO2), using MINIFACE technology, were studied in a Dutch lowland peatland dominated by Sphagnum and Phragmites for 3 years. We hypothesized that vascular plant carbon would accumulate in this peatland in response to CO2 enrichment owing to increased productivity of the predominant species and poorer quality (higher C/N ratios) and consequently lower decomposability of the leaf litter of these species. Carbon isotope signatures demonstrated that the extra 180 ppmv CO2 in enriched plots had been incorporated into vegetation biomass accordingly. However, on the CO2 sequestration side of the ecosystem carbon budget, there were neither any significant responses of total aboveground abundance of vascular plants, nor of any of the individual species. On the CO2 release side of the carbon budget (decomposition pathway), litter quantity did not differ between ambient and CO2 treatments, while the changes in litter quality (N and P concentration, C/N and C/P ratio) were marginal and inconsistent. It appeared therefore that the afterlife effects of significant CO2-induced changes in green-leaf chemistry (lower N and P concentrations, higher C/N and C/P) were partly offset by greater resorption of mobile carbohydrates from green leaves during senescence in CO2-enriched plants. The decomposability of leaf litters of three predominant species from ambient and CO2-enriched plots, as measured in a laboratory litter respiration assay, showed no differences. The relatively short time period, environmental spatial heterogeneity and small plot sizes might explain part of the lack of CO2 response. When our results are combined with those from other Sphagnum peatland studies, the common pattern emerges that the vascular vegetation in these ecosystems is genuinely resistant to CO2-induced change. On decadal time-scales, water management and its effects on peatland hydrology, N deposition from anthropogenic sources and land management regimes that arrest the early successional phase (mowing, tree and shrub removal), may have a greater impact on the vascular plant species composition, carbon balance and functioning of lowland Sphagnum–Phragmites reedlands than increasing CO2 concentrations in the atmosphere. [ABSTRACT FROM AUTHOR]

The rhizosphere influence on the soil microbiome and function of crop wild progenitors (CWPs) remains virtually unknown, despite its relevance to develop microbiome-oriented tools in sustainable agriculture. Here, we quantified the rhizosphere influence-a comparison between rhizosphere and bulk soil samples-on bacterial, fungal, protists and invertebrate communities and on soil multifunctionality across nine CWPs at their sites of origin. Overall, rhizosphere influence was higher for abundant taxa across the four microbial groups and had a positive influence on rhizosphere soil organic C and nutrient contents compared to bulk soils. The rhizosphere influence on abundant soil microbiomes was more important for soil multifunctionality than rare taxa and environmental conditions. Our results are a starting point towards the use of CWPs for rhizosphere engineering in modern crops., (© 2024 The Author(s). Ecology Letters published by John Wiley & Sons Ltd.)