The origins and evolutionary history of feral apples in southern Canada

Abstract

Feral populations of domesticated crops can establish through two nonmutually exclusive pathways: hybridization with native relatives and recruitment of and recombination between known cultivars. The extent and relative importance of these pathways is not known, especially for woody fruit crops. Here, we examined the evolutionary origins of feral populations of Malus domestica (domestic apple) in southern Canada using a population genetic analysis. We characterized genotypes of 578 putative feral apple trees and evaluated them in relation to genotypes of 156 commercial cultivars, 28 non‐native, ornamental crabapples and 47 native Malus coronaria trees using 14 microsatellite markers. No feral trees were genetic admixtures between domestic and native Malus; however, a minority of trees were admixed with introduced ornamental Malus. Feral trees and commercial cultivars both occurred in two major genetic groups and seven subgroups distributed throughout all commercial growing regions. A total of 42 cultivars, both heritage and currently grown, occurred in probable parental pairs for feral trees, with nine heritage varieties accounting for 72% of parental assignments. We conclude that feral apples in southern Canada are not products of hybridization with native M. coronaria but we cannot exclude ornamental apple species as contributing to the naturalization process. Nonhybrid feral domestic apples have multiple origins, with a prominent signature of early heritage cultivars. These lineages have spread and coexist throughout Ontario, rather than being derived strictly from local sources.

Microsatellite markers as a tool for active germplasm management and bridging the gap between national and local collections of apple

“…Conversely, the lack of overall differentiation could be taken to suggest that the majority of cultivars assessed in the fruitID scheme are likely to originate from a similar range of material to that which has been included within the NFC collection, and this would reflect the fact that many cultivars of apple have been brought into the UK from Europe and the rest of the world over the past centuries. Whilst many of the fruitID scheme samples were cultivars found in old orchards and gardens, a number of them were feral seedlings and these findings are also in agreement with the finding that feral seedlings in southern Canada were mostly descendants from the cultivated gene pool (Cronin et al 2020).…”

Enhancing crop diversity for food security in the face of climate uncertainty

“…De‐domesticates can be further defined as endo‐, exoendo‐ or exoferal. The first of these include some weedy rice species, Tibetan semi‐wild wheat, and feral rye, feral apple and feral olive, and are the result of spontaneous mutations in genes underlying key traits (Burger et al., 2006; Cronin et al., 2020; Guo et al., 2020; Londo and Schaal, 2007; Mekuria et al., 2002). The second includes some other weedy rice species, Tibetan weedy barley and feral Callery pear, all of which result from hybridization within landraces or different genotypes (Ishikawa et al., 2005; Pourkheirandish et al., 2018; Wu et al., 2021; Zeng et al., 2018).…”

Advanced genebank management of genetic resources of European wild apple, Malus sylvestris, using genome-wide SNP array data

“…It was included as a control the seedlings and some adult trees. Parentage reconstruction analysis to detect parent-offspring relationships was done for (1) the filtered unique M. sylvestris genotypes and (2) this set plus the set of 33 M. domestica varieties to enable the identification of feral trees (direct offspring of varieties) and of introgression events (plants with a relationship to M. domestica but less than direct offspring) (Cronin et al 2020).…”