Fragaria × bifera Duch.: Origin and taxonomy

In 1788 DUCHESNE described strawberry plants from the environs of Bargemon (France) as Fragaria bifera. These plants appeared to him as varying between the Wood Strawberry (Fragaria vesca L.) and the Breslinges (Fragaria viridis Weston). Since then, putative hybrids between wild-growing strawberries in Europe, especially between F. vesca and F. viridis, have been reported variously. Fragaria hagenbachiana described by KOCH in 1842 from the environs of Zunzingen (Germany) is probably one of these putative hybrids. Studies on 13 accessions of putative hybrids, a great many herbarium specimens representing the whole area, and molecular investigations have led us to propose that all these plants represent hybrids of the diploid (2n = 2x = 14) species Fragaria vesca and F. viridis. The valid name is F. × bifera Duch. Morphologically F. × bifera is a highly varying hybrid species that has probably originated many times and occurs throughout the area where the two parent species commonly occur. Up to now, 12 accessions are known to be diploid (2n = 14) and one triploid (2n = 21). From molecular studies, we have identified markers for the nuclear and chloroplast genomes of F. vesca and F. viridis in all of the hybrids investigated. In all cases F. vesca has acted as the female parent. Also, the triploid's nuclear genome constitution evidently includes two genome copies from F. viridis and one from F. vesca.