Caryologia (Feb 2023)
Polyploid cytotypes and formation of unreduced male gametes in wild and cultivated fennel (Foeniculum vulgare Mill.)
Abstract
Abstract. Foeniculum vulgare Mill. (2n=22) is an herbaceous species native to the Mediterranean region and naturalized in many temperate areas around the world. It includes subsp. piperitum and subsp. vulgare which constitute the wild and cultivated forms, respectively. Fennel is of economic importance not only as a vegetable crop but also for its wide use in the food and pharmaceutical industries. In recent years, the therapeutic and pharmacological potential of this species has been widely analyzed. Instead, a reduced interest has been directed to its cytogenetic traits. Therefore, the intention of this study was to gain more knowledge of the cytogenetics of this species by investigating some aspects so far neglected such as variations of its chromosome number and the occurrence of polyploidization events. By means of extensive chromosome counting, the presence of tetraploid cytotypes has been discovered both in wild and cultivated fennel. Moreover, the analysis of pollen and PMCs at the tetrad stage provided evidence supporting spontaneous sexual polyploidization as the most possible origin of the tetraploid cytotypes discovered. The findings realized by this study constitute the first evidence of the occurrence of polyploidization events in F. vulgare and suggest that the use of 2n gametes could be a valuable approach to the genetic improvement of this crop.
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