Hybridization between the linear-leaved Potamogeton species in Turkey

Hybridization is an important source of generating diversity in Potamogeton. However, the recorded frequency and distribution of hybrids in the world is highly uneven, and so is our knowledge of this diversity. So far, no hybrid between linear-leaved species has been recorded in Turkey. Morphologically intermediate and taxonomically unclear forms collected during an extensive field survey in wetlands throughout Turkey were subjected to detailed morphological and molecular analyses. Direct sequencing and cloning of the ITS region revealed two hybrids previously unknown in Turkey: P. obtusifolius x P. berchtoldii and P. trichoides x P. berchtoldii. Sequences of the chloroplast trnL-trnF intergenic spacer region confirmed P. obtusifolius and P. trichoides as maternal parents of these hybrids. One of the maternal species, P. obtusifolius, is not known to currently occur in Turkey. Brief morphological descriptions of the new hybrids are provided, as well as a comparison of diagnostic characters with those of all parental and similar linear-leaved species. These results demonstrate that hybridization studies and appropriate approaches bring important information about both past and present biodiversity.