Horticultural performance and QTL mapping of snap bean (Phaseolus vulgaris L.) populations with organic and conventional breeding histories

Authors: RICHARDSON, HAYLEY - Oregon State University; King, Ryan; DAVIS, JOEL - Oregon State University; MYERS, JAMES - Oregon State University

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/15/2025
Publication Date: 5/19/2025
Citation: Richardson, H.E., King, R., Davis, J., Myers, J.R. 2025. Horticultural performance and QTL mapping of snap bean (Phaseolus vulgaris L.) populations with organic and conventional breeding histories. Frontiers in Plant Science. 16. https://doi.org/10.3389/fpls.2025.1533039.
DOI: https://doi.org/10.3389/fpls.2025.1533039

Interpretive Summary: Improving crop cultivars for use on organic farms is pertinent, as current elite germplasm is less resilient within the more variable context of organic farm environments. Although a growing number of studies have focused on organic plant breeding in cereal crops, very few have focused on vegetable crops, especially those such as snap beans that are grown for both fresh market and processing use. In this study, we developed four families of inbred lines under parallel organic and conventional management; utilizing these populations, we explored how historic breeding history influenced the performance of snap bean progeny. Significant increases in germination speed and rate were observed, suggesting that beans bred within an organic production environment are more resilient to abiotic and biotic pressures in the soil. We also found that root branching density increased among organically-bred bean families, while root disease decreased in both the organically-bred bean families and the families resulting from crosses between 'OR5630' and 'Black Valentine’. After developing genetic maps for each of our four families, we identified chromosomal regions associated with days to germination, early-season vigor, root morphology, disease, days to flowering, and seed weight. This study lays the groundwork for improving snap bean germplasm for performance in organic systems by tracking the microevolutions created through long-term selection under organic or conventional management (i.e., breeding history). By understanding these shifts, plant breeders will begin to build a toolbox of genetic information that they can leverage in modern breeding work for organic crop cultivars.

Technical Abstract: Improving crop cultivars for use on organic farms is pertinent, as current elite germplasm is less resilient within the more variable context of organic farm environments. Although a growing number of studies have focused on organic plant breeding in cereal crops, very few have focused on vegetable crops, especially those such as snap beans (Phaseolus vulgaris) that are grown for both fresh market and processing use. We developed four populations of recombinant inbred lines under parallel organic and conventional management; utilizing these populations, we explored how historic breeding history influences the performance of snap bean progeny. We identified significant increases in germination speed and rate, which suggest that beans bred within an organic production environment are more resilient to abiotic and biotic pressures in the soil. We also found that root branching density increased among organically-bred bean families, while root disease decreased in both the organically-bred bean families and the populations with 'OR5630' × 'Black Valentine’ parentage. After developing linkage maps for each of our four populations, we identified QTL associated with days to germination, early-season vigor, root morphology, disease, days to flowering, and seed weight. This study lays the groundwork for improving snap bean germplasm for performance in organic systems by tracking the microevolutions created through long-term selection under organic or conventional management (i.e., breeding history). By understanding these shifts, plant breeders will begin to build a toolbox of genetic information that they can leverage in modern breeding work for organic crop cultivars.