The validation void: Mapping the research-to-adoption gap in agricultural innovation using the TRAIN framework—A review
Agricultural innovation holds significant potential to enhance productivity, sustainability, and rural livelihoods; yet many innovations remain confined to research output rather than achieving farmer adoption. A useful precedent for addressing this type of pipeline fragmentation exists in the health sciences, where translational research models have systematically tracked innovations from discovery to practice. Despite decades of investment in agricultural innovation systems, no framework traces the full journey from research output to sustained farmer adoption with the sequential precision applied in biomedical translational research. To examine where the innovation pipeline fractures and why, this paper presents a PRISMA-Scr scoping review of 357 studies screened from 14,303 records across Scopus, Web of Science, CAB Abstracts, Google Scholar, and grey literature repositories, coded against four-stage translational model: RIS (Research and Innovation Supply), VAL (Validation), BRAND (Branding and Packaging), and ADOPT (Adoption and Diffusion). Here we show for the first time that 60.8% of agricultural innovation studies address only a single translational stage, that validation remains the least documented function at 18.5%, and that the translational vocabulary that transformed biomedicine remains virtually absent as a named paradigm in agriculture. Studies incorporating BRAND activities covered an average of 44% more pipeline stages, identifying farmer-facing communication as the critical coupling between the technocratic and sociocultural dimensions of innovation, while Indonesia's 10 included studies reveal a complete validation gap and near-total absence of strategically designed BRAND activities. We propose the TRAIN (Translational Research-to-Adoption Innovation Nexus) framework, which conceptualizes the innovation pipeline as functionally distinct wagons on a directed train, enabling policymakers and researchers to diagnose translational gaps relative to specific thematic priorities and design programs that connect research to farmer reality.