Genetic diversity analysis of angled luffa germplasm resources based on phenotypic traits and resequencing data

Introduction: Phenotypic evaluation and whole-genome resequencing (WGR) techniques play critical roles in the identification and utilization of crop germplasm resources. This study integrated 28 phenotypic traits and WGR data to assessphenotypic variation and genetic diversity among 209 angled luffa (Luffa acutangula) accessions. Methods: A total of 209 angled luffa accessions were evaluated using 28 phenotypic traits and whole-genome resequencing. Phenotypic variation was assessed by coefficients of variation and Shannon-Wiener diversity indices. Principal component analysis (PCA), population structure analysis, phylogenetic tree construction, and hierarchical clustering were performed to analyze phenotypic and genetic diversity. Results: Extensive phenotypic variation was observed, with coefficients of variation for 20 quantitative traits ranging from 8.41% to 54.09%, and Shannon-Wiener diversity indices (H') from 1.79 to 2.51. For 8 quality-related traits, coefficients of variation ranged from 4.93% to 45.11%, with H' values between 0.13 and 1.97. Principal component analysis revealed 9 principal components, with fruit length and skin color exhibiting the highest loadings, enabling the identification of 12 superior germplasm accessions. Genetic diversity indices indicated limited overall genetic variation (Ne = 1.390, I = 0.528, Ho = 0.125, He = 0.236) with a high inbreeding coefficient (FIS = 0.470), indicating significant inbreeding within this population. Population structure, phylogenetic tree, and hierarchical clustering analyses consistently partitioned the accessions into six subgroups, with each subgroup displaying similar phenotypic and genetic characteristics. Discussion: Together, these findings provide an integrated phenotypic and genomic landscape of ridged loofah diversity and have laid a solid foundation for the innovative utilization, molecular genetic improvement, and new variety selection of angled luffa germplasm resources in the future.