Comprehensive Evaluation of 133 Fennel (Foeniculum vulgare Mill.) Germplasm Resources Based on Different Methods

To screen the high-quality germplasm resources of vegetable fennel (Foeniculum vulgare Mill.), 133 fennel accessions were systematically evaluated. Eleven agronomic traits were comprehensively analyzed using variation analysis, correlation analysis, principal component analysis (PCA), gray relational analysis (GRA), and cluster analysis. Results revealed that the coefficient of variation among accessions (CV_among) for quantitative traits ranged from 27.40% to 72.93%. The largest variation was observed in plant weight, indicating substantial potential for genetic improvement in this trait. Highly significant or extremely significant correlations were detected among most traits, especially between the leaf length and plant weight. PCA extracted the first six principal components. Their cumulative contribution rate reached 83.536%. The stem diameter, leaf length, leaf width and plant weight were the main traits that deserved attention. Based on comprehensive evaluation and weighted gray relational ranking, seven germplasm accessions consistently ranked within the top ten, showing higher composite scores under the conditions of this trial. Cluster analysis categorized all fennel accessions into four groups, among which Group IV exhibited the highest yield potential. Groups I and II, meanwhile, comprised individuals characterized by smaller plant size and distinct leaf morphology. These findings provide a preliminary methodological reference for the multivariate evaluation of vegetable fennel germplasm, and serve as a data basis for subsequent multi-environment trials and molecular marker-assisted selection.