Comprehensive Evaluation of Flowering Traits in Curcuma Germplasm Resources and Association Analysis of SSR Markers

Objective Phenotypic evaluation was performed on diverse Curcuma germplasm resources, followed by association analysis to identify markers significantly associated with flowering traits, thereby providing theoretical guidance for the breeding of superior new Curcuma varieties.

Method Genetic diversity was analyzed in 71 Curcuma germplasm resources using 42 pairs of highly polymorphic SSR markers. Sixteen phenotypic traits (including scape height, cape thickness, anthocyanin content, etc.) were systematically evaluated. By integrating genotypic and phenotypic data, molecular markers significantly associated with flowering-related traits were identified.

Result The Shannon diversity indices for the two descriptive traits are 0.534 and 0.322, respectively, indicating relatively low levels of diversity. The coefficient of variation for 14 quantitative traits ranges from 0.26 to 10.13, indicating the typical characteristics of continuously distributed quantitative traits. The correlation coefficients among the 16 traits ranged from -0.89 to 0.80, with most traits exhibiting significant positive correlations. 620 alleles (average14.76 alleles per locus) were discovered using 42 pairs of SSR markers, and the polymorphic information content (PIC) ranged from 0.46 to 0.96 with an average of 0.80, which indicated the high genetic diversity of tested Curcuma accessions. All the individuals were divided into two groups according to the results of structure and cluster analysis, suggesting their genetic relationships and specificities. Finally, 15 SSR markers were identified as significantly associated with 11 phenotypic traits, accounting for 14.62% to 25.93% of the phenotypic variation. Notably, CAL117 exhibited a highly significant association with the length of the upper bract, demonstrating the highest phenotypic explanation rate among all SSR markers.

Conclusion This study has identified SSR markers that are significantly associated with the major ornamental traits of the genus Curcuma. These findings offer novel markers for molecular-assisted breeding selection in Curcuma flowers and provide theoretical support for the cultivation of new Curcuma varieties with superior ornamental characteristics.