Evolutionary pathways to lower biomass allocation to the seed coat in crops: insights from allometric scaling

• Published in: The New phytologist Vol. 243; no. 1; pp. 466 - 476
• Main Authors: Milla, Rubén, Westgeest, Adrianus J., Maestre‐Villanueva, Jorge, Núñez‐Castillo, Sergio, Gómez‐Fernández, Alicia, Vasseur, François, Violle, Cyrille, Balarynová, Jana, Smykal, Petr
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.07.2024
• Subjects: Allometry; Biological Evolution; Biomass; biomass allocation; Crops; Crops, Agricultural - anatomy & histology; Crops, Agricultural - growth & development; Crops, Agricultural - physiology; Deviation; Domestication; Dormancy; Evolution; Lightweight; plant traits; Scaling; Seed coats; seed dormancy; seed size; Seeds; Seeds - anatomy & histology; Seeds - growth & development; Seeds - physiology; Weight reduction; allometry; seed dormancy; domestication; seed size; biomass allocation; plant traits
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/nph.19821

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.