Associated SNPs, heritabilities, trait correlations, and genomic breeding values for resistance in snap beans (Phaseolus vulgaris L.) to root rot caused by Fusarium solani (Mart.) f. sp. phaseoli (Burkholder)

Authors: HUSTER, ABIGAIL - Oregon State University; Wallace, Lyle; MYERS, JAMES - Oregon State University

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/23/2021
Publication Date: 4/28/2021
Citation: Huster, A., Wallace, L.T., Myers, J.R. 2021. Associated SNPs, heritabilities, trait correlations, and genomic breeding values for resistance in snap beans (Phaseolus vulgaris L.) to root rot caused by Fusarium solani (Mart.) f. sp. phaseoli (Burkholder). Frontiers in Plant Science. 12. Article 697615. https://doi.org/10.3389/fpls.2021.697615.
DOI: https://doi.org/10.3389/fpls.2021.697615

Interpretive Summary: Fusarium root rot disease of snap beans causes considerable losses every year to snap bean production in the U.S. and around the world. Cultural method for controlling the disease, such as crop rotations and wider spacing between plants in the field, are ineffective and fields that are free of disease can be infested after only a single year. Consequently, the development of new varieties with improved genetic resistance is the best approach for effective and sustainable disease control. The objectives of this study were to evaluate a diverse collection of snap beans for resistance to Fusarium root rot, detect DNA markers associated with disease resistance, and identify snap beans that can be used as parents for improving resistance in commercial varieties. We determined what root traits, such as total mass of roots and the angle at which the roots penetrate soil, were best for evaluating disease resistance. We also detected five different DNA markers associated with resistance and several promising snap bean materials (accessions) that can be used as parents. These results provide breeders with several tools to accelerate the development of new snap bean varieties with improved levels of resistance to this globally destructive disease.

Technical Abstract: Root rot disease of snap bean (Phaseolus vulgaris) caused by the fungus Fusarium solani f.sp. phaseoli is a major constraint to commercial snap bean production in the United States and around the world. Genetic resistance is needed to effectively control disease because cultural control methods are ineffective and the pathogen can infest previously clean land after a single season of production. A diversity panel of 148 snap bean accessions was evaluated for resistance to Fusarium root rot in Oregon. Morphological traits potentially associated with root rot resistance, such as aboveground biomass, adventitious roots, taproot diameter, basal root diameter, deepest root angle, shallowest root angle, root angle average, root angle difference, and root angle geometric mean were evaluated and correlated to disease severity. A genome-wide association study (GWAS) using the Fixed and random model Circulating Probability Unification (FarmCPU) statistical method, identified five associated single nucleotide polymorphisms (SNPs) for disease severity and two SNPs for biomass. The SNPs were found on Pv03, Pv07, Pv08, Pv10, and Pv11. Superior breeding materials were identified through ridge regression best linear unbiased prediction (rrBLUP) for genomic estimated breeding values (GEBV). Heritabilities were also determined. This research identified root traits and molecular markers associated with disease resistance along with promising snap bean accessions that can be used to develop snap bean varieties with enhanced resistance to Fusarium root rot.