Regional Disparities Call for Defining the Target Population of Environments (TPEs) and the Breeding Strategies for Sustainable Agriculture: A Case Study on Rice Improvement in Vietnam

This study examines the socio-demographic characteristics, rice production practices, and breeding preferences of farmers across three major rice-growing regions of Vietnam: the Mekong Delta, Central Vietnam, and North Vietnam. A survey of 109 rice farmers captured information on cultivation status, livelihood activities, and preferred breeding traits for rice improvement. The results reveal clear regional differentiation in farm structure, production objectives, and varietal preferences. Rice farming in the Mekong Delta is predominantly commercially oriented, characterized by larger landholdings and greater male participation, whereas rice production in Central and Northern Vietnam is more subsistence-oriented, with higher female involvement. Farmers across regions consistently valued locally adapted rice varieties, but articulated region-specific trait priorities shaped by agro-ecological conditions. In the Mekong Delta, preferences emphasized soft grain quality and salinity tolerance, reflecting coastal production constraints. In Central Vietnam, farmers prioritized heat tolerance and resistance to pests and diseases, while in Northern Vietnam, cold tolerance and grain quality attributes, including aroma and harder texture, were most important. Major biotic stresses, particularly blast and bacterial blight, also showed significant regional variation in reported incidence. By linking these region-specific preferences to clearly defined Target Populations of Environments (TPEs), this study provides a practical framework for aligning breeding targets with real-world production conditions. The findings offer actionable guidance for participatory breeding and decentralized varietal evaluation under the Biodiversity for Opportunities, Livelihoods, and Development (BOLD) initiative, as well as other rice improvement programs. To our knowledge, this represents the first multi-region evidence from Vietnam that systematically integrates agro-ecological variation with a TPE-based breeding approach, supporting the development of climate-resilient, farmer-preferred rice varieties and more sustainable rice production systems.