Genome-Wide Association Studies Provide Molecular Insights into the Genetic Determination of the Fruit Shape-Related Traits of Actinidia eriantha

In the selection of new horticultural crops varieties, fruit shape and size are key agronomic traits targeted by breeders, as well as critical criteria for commercial evaluation and grading. Wild germplasm resources typically exhibit greater genetic diversity in fruit morphology compared to cultivated varieties. The study analyzed fruit shape-related traits of 216 Actinidia eriantha plants from a wild population in Jiangxi Province, China, and identified significant associated single nucleotide polymorphisms (SNPs) and candidate genes for the target traits using genome-wide association analysis (GWAS). The results revealed substantial phenotypic variation in fruit shape- and size-related traits. A total of 115 SNPs and 349 putative coding genes were significantly associated with 7 fruit shape-related traits. Within the candidate genomic regions, we identified several key genes linked to specific morphological features, including F-box and MADS4, previously reported to influence fruit shape; WOX, F-box, and OVATE, associated with fruit shape index; RING-type E3 ubiquitin transferase, correlated with transverse diameter; and PLATZ, COL, and Aux/IAA, implicated in fruit weight regulation. These findings facilitate the precise identification of genes or quantitative trait loci (QTLs) governing fruit morphology. Furthermore, the associated SNP markers provide valuable tools for marker-assisted breeding, enabling the development of elite cultivars with desirable fruit characteristics.