Introduction: Fennel (Foeniculum vulgare Mill.) is an old medicinal plant that is usually used as food and traditional medicine. The main goal of studying genetic diversity and relationships between germplasm sets is to use the information obtained from the diversity of native cultivars to develop and release cultivars with higher yields among cultivated species.
Materials and methods: To investigate genetic diversity and relationships among morphological traits, an experiment was performed using a completely randomized design with 3 replications on 11 fennel ecotypes in the greenhouse of Payame Noor University of Qom, in 2020. The measured traits included number of days to germination, number of days to 50% flowering, number of days to maturity, plant height, the number of branches per plant, the number of umbels per plant, the number of umbellets per umbel, the number of flowers per umbellets, 1000-seed weight, and grain yield per plant. After data collection, analysis of variance, mean comparison (with Duncan's test), correlation between traits (using Pearson's method) and stepwise regression were performed. In order to determine the relative contribution of each of the measured traits in creating diversity among the studied ecotypes, factor analysis was used, and Ward's cluster analysis was used to group them. SPSS software was used to analyze the data. Environmental, genetic and phenotypic variance components were estimated based on mathematical expectation of mean squares to calculate trait heritability with Excel software.
Results and discussion:Based on the results of the analysis of variance, a significant difference was observed among the studied ecotypes for all traits. Most of the studied traits had high broad-sense heritability. Seed yield per plant had a positive and significant correlation with the number of umbellets per umbel (0.64), number of umbels per plant (0.59), and number of branches per plant (0.56). Factor analysis showed that three main and independent factors explained 78.74 percent of the total variance in all ecotypes. Cluster analysis using the Ward method grouped 11 studied ecotypes into four separate clusters. The second cluster ecotypes (Ardebil and Moghan) are valuable due to their high values of plant height, number of branches per plant, number of umbels per plant, number of umbellets per umbel, number of flowers per umbellets, 1000-seed weight, and seed yield, and these ecotypes can be used to select of high yielding ecotypes and desirable morphological traits in breeding programs.
Conclusion:The results showed that fennel ecotypes had many differences in terms of the studied traits. Among them, the early maturing ecotypes (Ardebil and Moghan) with high values of the number of umbels per plant, umbellets per umbels and flowers in umbellets, and number of branches per plant had high seed yield. While long maturing ecotypes (Hajiabad, Qazvin, Sardasht and Sari) with low values of the number of umbels per plant, umbellets per umbels and flowers per umbellets, the number of branches per plant had low seed yield. Therefore, in order to produce ecotypes with desirable agricultural characteristics in breeding and selection programs, crossing between superior ecotypes from different clusters and testing their results can be done. The results of stepwise regression analysis were consistent with correlation analysis, so that the number of umbellets per umbels, which had the highest correlation coefficient with yield, was entered into the model as the first trait. The next trait, the number of umbels per plant, was entered into the model, which had a positive and significant correlation with yield. Considering that the traits number of umbels per plant and number of umbellets per umbels were good indicators for yield, therefore, the selection of these traits can cause the maximum increase in yield compared to other traits of yield components. In this research, the ecotypes of Ardebil and Moghan are introduced as superior ecotypes, which can be used to apply all kinds of improvement methods on them and achieve the ecotypes with favorable morphological characteristics.