Participatory plant breeding of sweetcorn for adaptation at diverse Spanish locations

Sweet corn homozygous for the shrunken2 ( sh2 ) mutation exhibits narrow genetic diversity and limited adaptation to diverse environments. This study aimed to assess whether participatory plant breeding (PPB), led by farmers in specific environments, can enhance adaptation and generate phenotypic diversity associated with local conditions without compromising quality. Starting from the synthetic sweet corn population EPS18 — originally developed in the Spanish province of Pontevedra and with low genetic diversity — three PPB selection cycles were conducted in three ecologically distinct Spanish provinces: Lugo, Burgos, and Barcelona. The third selection cycle from each location was evaluated alongside the original EPS18 population and four commercial hybrids in both Pontevedra (the original site) and Burgos (the most environmentally challenging site). Temperature and water availability emerged as the primary environmental factors influencing selection outcomes. Yield and plant growth were the most affected traits, while quality parameters remained largely unchanged. These results demonstrate that PPB can effectively improve the adaptation of a genetically narrow sweet corn population to diverse northern Spanish environments without sacrificing quality. We conclude that selection for local adaptation through PPB can successfully induce phenotypic diversity in traits related to plant growth and yield, driven by environmental variables — particularly temperature and water availability — while maintaining desirable quality traits.