Phenotypic and genetic characterization of the Lentil Single Plant-Derived core collection for resistance to root rot caused by Fusarium avenaceum.

Lentil (Lens culinaris, Medik.) is a pulse crop grown for its amino acid profile, moderate drought tolerance, and ability to fix nitrogen. As the global demand for lentils expands and new production regions emerge so too have the complement of diseases that reduce yield, including the root rot complex. Although the predominant causal pathogen varies based on growing region Fusarium avenaceum is often found to be an important contributor to disease. This study screened part of the Lentil Single Plant-Derived Core Collection for resistance to F. avenaceum in a greenhouse. Plants were phenotyped for disease severity using three scoring scales and the differences in biomass traits due to pathogen presence were measured. Lentil accessions varied in disease severity and differences in biomass traits were found to be correlated with each visual severity estimate (r = -0.37 to -0.63, P < 0.001), however, heritability estimates were low to moderate among traits (H2 = 0.12 to 0.43). Results of a genome-wide association study (GWAS) using SNP markers derived from genotyping-by-sequencing revealed 11 QTL across four chromosomes. Two pairs of QTL co-located for two traits and were found near putative orthologs that have been previously associated with plant disease resistance. The identification of lentil accessions that did not exhibit a difference in biomass traits may serve as parental material in breeding or in the development of bi-parental mapping populations to further validate and dissect the genetic control of resistance to root rot caused by F. avenaceum.