Exploring the trade‐off between individual fitness and community performance of wheat crops using simulated canopy shade

Abstract

The genetic heritage of wheat (Triticum spp.) crops has been shaped by millions of years of predomestication natural selection, often driven by competition among individuals. However, genetic improvements in yield potential are thought to involve selection towards reduced competitiveness, thus enhancing adaptation to the crop environment. We investigated potential trade‐offs between individual plant fitness and community performance using a population of introgression lines carrying chromosome segments of wild emmer (nondomesticated) in the background of an elite durum cultivar. We focused on light as a primary factor affecting plant–plant interactions and assessed morphological and biomass phenotypes of single plants grown in mixtures under sunlight and a simulated canopy shade, and the relevance of these phenotypes for the monoculture community in the field. We found that responses to canopy shade resemble responses to high density and contribute to both the individual and the community. Stepwise regressions suggested that grain number per spike and its persistence under shade are essential attributes of productive communities, advocating their use as a breeding target during early‐generation selection. Overall, multiple phenotypes attained under shade could better explain community performance. Our novel, applicable, high‐throughput set‐up provides new prospects for studying and selecting single‐plant phenotypes in a canopy‐like environment.

Balancing grain yield trade-offs in ‘Miracle-Wheat’

“…In principle, field-grown plants experience competition for various resources, including light (Huber et al , 2021; Postma et al , 2021), especially in the inner rows (Rebetzke et al , 2014). In this regard, future studies investigating the response of various source and sink component traits in high-density plots or simulated canopy shade (Golan et al , 2022) are required to uncover the genetic framework of plant-plant competition and its effect on spike-branching expressivity.…”

Agroecological genetics of biomass allocation in wheat uncovers genotype interactions with canopy shade and plant size

“…To elucidate the genetic basis underlying the investment strategy of individual wheat plants and how it is influenced by canopy shade, we grew recombinant inbred lines in a mixture under natural sunlight and simulated canopy shade (Golan et al ., 2023) to obtain the biomass of the leaves, stems, spikes, and grains. Two complementary approaches were employed using organ masses to investigate the genetic factors influencing plasticity in biomass allocation: The first approach involved calculating mass fractions and utilizing a residual method to account for plant size effects.…”

“…The glasshouses had two open sides with porous metal netting to allow air circulation. Canopy shade was simulated using a green plastic filter (Lee122 Fern green; LEE filters, Andover, UK), as previously described (Golan et al, 2023), reducing the irradiation of blue and red light by c. 80% and resulting in a reduction of the red/far-red (715-745 nm) ratio from 1.13 to 0.28. The photosynthetically active radiation (PAR) under the simulated canopy shade was reduced by c. 55%.…”

“…Recent studies have shown a strong correlation between responses to plant density and to low light, indicating that the scarcity of light is often a limiting factor in high‐density crop communities (Poorter et al ., 2019; Postma et al ., 2021). The performance of individual plants cultivated under simulated shade shows stronger correlations with the performance of the monoculture community than individuals grown under natural sunlight conditions (Golan et al ., 2023). Practices such as tillage, fertilizing the soil, and regulating the water supply can reduce competition for water and nutrients, but they amplify competition for light.…”

Trade‐offs in plant responses to the environment

“…As the exploration of trade‐offs grows, there will be an increasing need for accessible and relevant experimental systems. Golan et al (2023) describe one such system in wheat to study the trade‐off of individual plant fitness and community performance. Additional innovation in experimental systems aimed at studying trade‐offs at different scales and under different environmental conditions will be needed to drive this field forward.…”