Orobanche cumana is a holoparasitic plant naturally distributed from central Asia to south-eastern Europe, where it parasitizes wild Asteraceae species. It is also an important parasitic weed of sunflower crops. The objective of this research was to investigate genetic diversity, population structure, and virulence on sunflower of O. cumana populations parasitizing wild plants in eastern Bulgaria. Fresh tissue of eight O. cumana populations and mature seeds of four of them were collected in situ on wild hosts. Genetic diversity and population structure were studied with SSR markers and compared to weedy populations. Two main gene pools were identified in Bulgarian populations, with most of the populations having intermediate characteristics. Cross-inoculation experiments revealed that O. cumana populations collected on wild species possessed similar ability to parasitize sunflower to those collected on sunflower. The results were explained on the basis of an effective genetic exchange between populations parasitizing sunflower crops and those parasitizing wild species. The occurrence of bidirectional gene flow may have an impact on wild populations, as new physiological races continuously emerge in weedy populations. Also, genetic variability of wild populations may favour the ability of weedy populations to overcome sunflower resistance mechanisms.

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Iridaceae is a family of perennial plants with almost worldwide distribution. The taxonomy of the family is based mainly on

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For a long time, the Balkan endemic species Crocus pallidus has been unconfirmed and neglected for the flora of Bulgaria. It has remained an uncertain species from the Balkans, often listed as a synonym of C. weldenii. The morphological resemblance to the albinistic forms of C. chrysanthus has led to incorrect identification in the past, resulting in uncertainty regarding the distribution of this species in Bulgaria. In this regard, a detailed morphological and anatomical study of Bulgarian natural populations was carried out. A phylogenetic comparison in the ITS region of two Bulgarian populations of C. pallidus with other related species was conducted, revealing the distinction of C. pallidus populations from the closely related C. weldenii. The recently described new endemic species from Turkey, C. thracicus, shows very similar morphological and anatomical characteristics to C. pallidus and logically continues the distribution range in Eastern Thrace, along the Black Sea coast. We have a basis for suggesting that it should be treated as a synonym of C. pallidus.