Genetic Diversity Analysis of Water Lily Germplasms Based on Morphological Traits and SSR Markers

The study was conducted to identify and describe 34 morphological traits from 30 collected tropical water lily germplasms, including both viviparous and non-viviparous water lilies, along with a genetic diversity analysis utilizing 16 selected polymorphic SSR markers. The results revealed significant differences among various water lily germplasms. Specifically, the genetic diversity index for 15 qualitative traits ranged from 0.456 to 1.681, while the index for 19 quantitative traits exceeded 1.5, ranging from 1.532 to 2.024. and the coefficient of variation for these traits varied between 12.11% and 58.88%, indicating that the genetic diversity index of quantitative traits was significantly higher than that of qualitative characteristics. Seven principal components were extracted, accounting for 74.16% of the genetic information. By integrating the calculation of membership function values, germplasms with superior comprehensive characteristics were selected, including N. 'Purple Joy', N. 'Key Largo', and N. 'Eldorado'. A total of 115 alleles were amplified using 16 pairs of SSR markers from the tested materials. The effective allele number (Ne) ranged from 2.01 to 8.02, Shannon's information index (I) varied from 1.03 to 2.25, polymorphism information content (PIC) ranged from 0.57 to 0.90, and the genetic similarity coefficient was from 0.30 to 0.80. Based on the morphological traits and SSR molecular markers, the tested water lily germplasms were classified into four and five categories, respectively, showing certain similarities and differences. The morphological clustering effectively distinguished between viviparous and non-viviparous water lilies, while the SSR-based clustering did not show a significant correlation with viviparity. Principal component analysis indicated that different groups were relatively independent, while individuals within each group were concentrated. These results suggest that combining morphological traits and SSR analysis is an effective approach for evaluating the genetic diversity of water lilies and understanding the genetic relationships among germplasms and provide a valuable reference for utilizing viviparous germplasms and breeding new varieties.