Abstract Background Crown imperial (Fritillaria imperialis L.) is a threatened bulbous plant which has great ornamental and medicinal values and importance. In the present study, a total of 100 specimens of wild-growing F. imperialis from 10 natural areas of Markazi province, Iran, representing one of the main centers of genetic diversity of this species, were evaluated using 37 phenotypic attributes during April 2021. Results High level of genetic variation within populations (75%) and low levels of genetic variation among populations (25%) was revealed. The highest coefficient of variation (CV) was found in leaf trichome (82.00%) and then margin of crown leaves (80.44%). In addition, flower color (CV = 50.86%), flower number (CV = 44.61%), peduncle diameter (CV = 33.44%), and plant length (CV = 32.55%)—all important from an ornamental point of view- showed relatively high CV values. The CV was the lowest for flower shape, filament color, bulb shape, bulblet number, and floral scent. Ward cluster analysis identified two main clusters, containing 14 and 86 specimens, respectively. The first group consisted mainly of specimens from the adjacent Shahbaz and Rasvand populations. According to the principal component analysis (PCA), the first six components of data accounted for 88.36% of total variance. The Shahbaz-1, Shahbaz-2, Shahbaz-6, Shahbaz-7, Shahbaz-9, and Bolagh-8 specimens showed the highest variation and were separated from others, which they can be used further in breeding programs, while Sarchal-2, Bolagh-3, and Chepeqli-4 specimens showed the lowest variability. Moreover, the studied populations were clustered into four distinct groups, each including populations that were geographically close to one another. Conclusions Although the examined specimens revealed high genetic diversity herein, the results indicated that wild-growing populations of F. imperialis are still at risk suffering from overcollection in the most of studied areas, especially in Deh-S
