Two-Part QTL Mapping Reveals Genetic Determinants of Fusarium graminearum resistance in Soybean

Authors: DETRANALTES, CHRISTOPHER; MA, JIANXIN - PURDUE UNIVERSITY; Song, Qijian; Cai, Guohong

Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 3/31/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: N/A

Technical Abstract: Soybean seedling disease (SSD) remains one of the largest causes of soybean yield loss in the United States. Recent surveys have pointed towards the growing predominance of Fusarium graminearum among the causal agents of SSD. We developed an F2:3 mapping population consisting of single seed descent derived progeny from a cross between partially resistant line PI 438500 and susceptible line PI 548631. The population of 234 progeny lines was phenotyped using a F. graminearum isolate on a 0-5 visual severity scale and genotyped with the BARCSoySNP6K assay. A preliminary two-part model approach, first modelling germination as a binary trait followed by simple interval mapping of surviving seedling’s visual severity scores, was applied to identify quantitative trait loci (QTL) underlying the F. graminearum resistance carried by PI 438500. Through this analysis, two significant QTL were detected and localized to chromosome 3 and 17. Logarithm of the odds (LOD) intervals surrounding the peak markers of each QTL defined the QTL to 234 kb and 483 kb regions, with estimated additive effects to the measure of visual severity of 0.60 and 0.54, respectively. Interestingly, heterozygotes at both loci exhibited a lethal phenotype. Our work enhanced understanding of the complex polygenic genetic architecture underlying soybean resistance to SSD.