Authors: M À Conesa M Mus J A Rosselló
Publish Date: 2008/05/14
Volume: 273, Issue: 3-4, Pages: 169-177
Abstract
Viola jaubertiana Marès Vigin is a narrow endemic violet of the Balearic Islands restricted to small fragmented and scattered populations living in inaccessible rocky places and calcareous overhangs V jaubertiana is entirely glabrous and morphologically very uniform However several authors have reported hairy individuals collected at the type locality suggesting that these rupicolous pubescent plants are putative hybrids with V alba Bess subsp dehnhardtii Ten W Becker a woodland violet growing in the area Ribosomal ITS sequences of the putative hybrids analysed showed additive speciesspecific sites of V alba subsp dehnhardtii and V jaubertiana strongly supporting its hybrid origin from these progenitors CpDNA sequences of all putative hybrids were uniform and identical to those present in V jaubertiana accessions This suggests that the gene flow between V alba subsp dehnhardtii and V jaubertiana is unidirectional and identifies the endemic V jaubertiana as the unique ovule donor The additivity of the ITS sequences together with the pollen and ovule sterility suggests that the sampled individuals are primary F1 hybrids whereas no trace of introgressive hybridization or hybrid zone has been evidenced by the nuclear and plastid markers used Judging from herbarium sheets hybridization between V alba subsp dehnhardtii and V jaubertiana is recurrent and dates back from the XIXth century Hybrids between these species are not linked to disturbed environments In fact they have been always reported in rupicolous habitats where the maternal species is restrictedWe are indebted to our colleague Arántzazu Molins for her generous help throughout the field sampling and lab work Relevant samples were provided by Pere Fraga and the staff of the Botanical Garden of Sóller Balearic Islands We thank Gonzalo NietoFeliner for friendly discussions and the comments of two anonymous reviewers that improved the manuscript This work has been partially funded by the CGL200760550/BOS project
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