Scaling law links plant growth variation to grain yield in wheat stands

Abstract

Growth rate, a fundamental biological trait influencing plant resource use, scales predictably with plant mass, following remarkably consistent allometric power laws shaped by biophysical constraints and natural selection. However, how these laws apply to crop plants shaped by artificial selection, and how they manifest in agronomic traits, remains undefined. Under controlled greenhouse conditions, we quantified the relationship between plant mass and growth rate in 195 European winter wheat cultivars. We uncovered genetic variation in allometry linked to plant size, where increased leaf allocation and faster development elevated allometric exponents. Phenotypic and genetic analyses revealed adaptive strategies, ranging from large, slow-growing genotypes that support reproductive initiation to small, fast-growing genotypes that enhance reproductive effort. A shared genetic basis--associated with Photoperiod response-1 (Ppd-1)--linked growth allometry in the greenhouse to genotype-by-environment interactions for grain yield in field trials. This variation in growth allometry, shaped by breeding in diverse environments, reflects strategies that enhance adaptation to weather conditions. Our findings demonstrate that growth allometry is biologically robust and agronomically important because it scales to wheat yield under diverse, realistic field conditions.