Crossability Between Wild (Malus sylvestris) and Cultivated (M. x domestica) Apples

Abstract

Malus sylvestris, a native fruit tree of Europe, is believed to be threatened by hybridization with the omnipresent cultivated apple (Malus x domestica). In the present study a series of controlled crossings were carried out in order to establish whether M. sylvestris can hybridize with its near relative, M. x domestica. By looking at fruit set, seed production, germination percentages, and development of seedlings following inter- and intraspecific crossings, no indication of neither pre- nor postzygotic barriers to hybridization between the two species was found. This can have important implications for management of the genetic resources of M. sylvestris.

Hybridization and Genetic Diversity in Wild Apple (Malus sylvestris (L.) MILL.) from Various Regions in Germany and from Luxembourg

“…Genetic barriers in general to interspecific hybridization within the subfamily Maloideae are described to be weak (KORBAN, 1986). Indications of pre-and postzygotic barriers to hybridization between wild and cultivated apples could not be found (LARSEN et al, 2008). Even so, an extent of 11% to 14 % of hybrids across several European countries occurs.…”

“…Both mechanisms of isolation have been thought to hinder hybridization primarily in populations in Denmark; e.g. only slight overlapping flowering periods, generally later flowering of cultivars (LARSEN et al, 2008) and pollination mostly within short distances of approx. 23 m (LARSEN and KJAER, 2009) were observed.…”

Pollen mediated gene flow in a native population of Malus sylvestris and its implications for contemporary gene conservation management

“…It is subject to risk of hybridization with cultivated species of Malus; the major risk being inferred by the omnipresent domesticated apple, Malus 9 domestica Borkh. (Stephan et al 2003;Larsen et al 2006Larsen et al , 2008. Further, M. sylvestris of non-local origin has been planted for decades in shelterbelts and amenity plantings in the landscape, subjecting the original gene pool to gene flow from the imported origins.…”

Malus ×oxysepala (M. domestica Borkh. × M. sylvestris Mill.) – a new spontaneous apple hybrid

“…Numerous species, and even more numerous cultivars, are grown for ornamental purposes in parks, in housing district green areas, and in large city green areas. In Poland, these include the following taxa: Malus baccata, M. floribunda, M. pumila, M. ×purpurea, M. ×scheideckeri, and M. sieversii [3].There are no genetic barriers between M. sylvestris and M. domestica [4]. Although literature sources in the description of M. sylvestris state that, at present, it is hardly ever found in the pure form because it frequently crosses with cultivars [1,[5][6][7], a description of the hybrid species is nowhere to be found [8][9][10][11][12][13][14][15][16].…”

“…There are no genetic barriers between M. sylvestris and M. domestica [4]. Although literature sources in the description of M. sylvestris state that, at present, it is hardly ever found in the pure form because it frequently crosses with cultivars [1,[5][6][7], a description of the hybrid species is nowhere to be found [8][9][10][11][12][13][14][15][16].…”