Genome-Wide Association Study on Lodging Resistance-Related Traits in Oats

Oat (<i>Avena sativa</i> L.), as an essential dual-purpose grain and forage crop, exhibits lodging resistance as a key factor directly impacting yield and quality. Therefore, breeding new oat varieties with lodging resistance is important to increase crop productivity and economic benefits. Using 130 oat germplasm as materials, 7 lodging resistance-related traits of oat, including plant height (PH), the fresh weight of single stem (FWSS), the length of basal second internode (LBSI), diameter of basal second internode (DBSI), wall thickness of basal second internode (WTBSI), stem breaking strength (SBS), and stalk puncture strength (SPS), were investigated in two experimental sites for one year. The results indicate that the seven lodging resistance-related traits exhibit a continuous distribution overall and generally follow a typical distribution pattern. A total of 36,928,068 high-quality Single-nucleotide polymorphisms (SNPs) generated from whole-genome resequencing were used for genome-wide association study (GWAS). Based on the BLINK (Bayesian-information and Linkage-disequilibrium Iteratively Nested Keyway) model threshold (-log₁₀(P) ≥ 6), 379 quantitative trait nucleotides (QTNs) associated with lodging resistance-related traits were identified. Among them, 38, 34, 78, 66, 55, 18, and 94 QTNs were associated with PH, FWSS, SBS, SPS, LBSI, DBSI, and WTBSI, respectively. Notably, three QTNs associated with FWSS and one QTN associated with SBS were stably detected across both environments, representing valuable markers for molecular breeding. From these loci, 54 candidate genes were annotated. Ranked by the number of candidate genes per trait, LBSI contained the highest number (14), followed by WTBSI (12), SPS (11), SBS (7), PH (5), and FWSS (5). Our findings provide critical support for analyzing the genetic mechanism of oat lodging resistance. Moreover, this study also offers a material and theoretical basis for the subsequent development of molecular markers and the breeding of new lodging-resistant oat varieties.