Toward Ratoon Biology of whole-plant regeneration across seasons

Ratoon-based cropping systems have re-emerged as a strategy to enhance productivity and resource use efficiency in crop production; however, the mechanisms governing regeneration across harvest cycles remain poorly understood, resulting in highly variable and unpredictable performance. Ratoon yield depends on two tightly coupled components: the establishment of reproductive tillers that form yield bearing units and the productivity of each unit, which were determined by organ differentiation and biomass accumulation. Here, we propose Ratoon Biology as a conceptual framework that redefines ratooning as a continuous, whole-plant developmental process that extends across seasons. We identify five interacting dimensions that jointly regulate ratoon productivity. First, ratoon buds determine regenerative potential through their meristem viability, dormancy status, and competitive competence. Second, stubble functions provide the structural and metabolic foundation for regeneration by maintaining vascular continuity, supplying carbon and nitrogen reserves, and integrating systemic signals. Third, root–shoot coordination enables the rapid re-establishment of hydraulic, nutritional, and hormonal coupling between residual roots and emerging shoots, thereby supporting early tiller vigor. Fourth, tiller regeneration and establishment represents a selective developmental process shaped by nodal competition, spatial heterogeneity, and unequal access to internal resources, which together determine which buds survive to become productive tillers. Fifth, inter-seasonal continuity reflects the developmental and physiological legacy linking the main crop to subsequent ratoon performance through structural, metabolic, and regulatory carry-over effects. Ratoon Biology thus provides a foundation for dissecting the biological basis of regenerative capacity and for guiding future management and breeding strategies aimed at achieving stable multi-season productivity.