The logical structure of the American strawberry healthy plant propagation system and the development path of strawberry plant industry in China

Strawberry is one of the most economically important crops in protected horticulture in China and a typical asexually propagated species, whose sustainable industrial development relies heavily on the stable supply of healthy nursery plants. Currently, China's strawberry nursery sector is still dominated by small-scale and decentralized propagation systems, resulting in unclear plant origin, frequent virus transmission, uneven plant quality, and difficulties in achieving standardized and large-scale production. These issues have become major constraints on the modernization and branding of the strawberry industry. In contrast, the United States has established a highly integrated strawberry clean plant system through the combination of the National Clean Plant Network (NCPN), regionally differentiated and hierarchical propagation, and government-led certification and regulatory supervision. This system is characterized by virus elimination and testing at the source, multi- level regionalized propagation, mechanized large- scale production, and standardized traceability management, ultimately achieving both“clean plant sources”and“clean propagation processes”. Taking the California strawberry nursery system as a representative example,“virus-free nuclear stock plants (G1)”are produced and maintained within high-isolation NCPN clean plant centers following thermotherapy and comprehensive pathogen testing. These nuclear plants serve as the primary source of propagative material with the highest health status. Certified nurseries subsequently propagate G1 plants under strict isolation and management conditions to establish G2 foundation plants. Under the supervision of the California Department of Food and Agriculture (CDFA), further propagation is conducted in registered nurseries to produce G3 registered plants through mandatory registration, inspection, and multi- round pathogen testing. Finally, G3 plants are multiplied in production nurseries to generate G4 certified plants, which are supplied for commercial strawberry fruit production. Throughout the entire process, government certification, labeling, and traceability systems ensure clear health classification, origin transparency, and regulatory compliance. Based on a systematic review of the U.S. operational mechanisms and practical experience, this paper analyzes the structural advantages and key constraints of China's strawberry nursery industry and proposes a development pathway with Chinese characteristics. Futhermore, it is recommended that China establish a national clean plant network relying on existing testing and research platforms, construct a regionally coordinated multi-level propagation system by integrating climatic and facility advantages, and promote pilot implementation of certification, labeling, and traceability mechanisms in major nursery regions. Through these measures, a three-in-one nursery system comprising a“national network + regional leading enterprises + certification supervision”can be established, facilitating the implementation of the Seed Industry Revitalization Strategy in the strawberry sector and providing a reference for building a national clean fruit plant network.