Ecological and evolutionary drivers of phenotypic and genetic variation in the European crabapple [Malus sylvestris(L.) Mill.], a wild relative of the cultivated apple

Abstract

Background and Aims Studying the relationship between phenotypic and genetic variation in populations distributed across environmental gradients can help us understand the ecological and evolutionary processes involved in population divergence. We investigated the patterns of genetic and phenotypic diversity in the European crabapple, Malus sylvestris, a wild relative of the cultivated apple (Malus domestica) that occurs naturally across Europe in areas subjected to different climate conditions, to test for divergence among populations. Methods Growth rates and traits related to carbon uptake in seedlings collected across Europe were measured under controlled conditions and associated with the genetic status of the seedlings, which was assessed using 13 microsatellite loci and Bayesian clustering method. Isolation-by-distance, -by-climate, and -by-adaptation patterns, which can explain genetic and phenotypic differentiation among M. sylvestris populations, were also tested. Key Results A total of 11.6% of seedlings were introgressed by M. domestica, indicating that crop-wild gene flow is ongoing in Europe. The remaining seedlings (88.4%) belonged to seven M. sylvestris populations. Significant phenotypic trait variation among M. sylvestris populations was observed. We did not observe significant isolation-by-adaptation; however, the significant association between genetic variation and the climate during the last glacial maximum suggests that there has been local adaptation of M. sylvestris to past climates. Conclusions This study provides insight into the phenotypic and genetic differentiation among populations of a wild relative of the cultivated apple. This may help us better utilize its diversity and provide options for mitigating the impact of climate change on the cultivated apple through breeding.

Morphological variation in blackthorn (<i>Prunus spinosa</i> L.) populations in the Northwestern part of the Balkan Peninsula - Absence of geographical and environmental structure

“…(Demesure et al, 2000;Kučerová et al, 2010), Malus sylvestris (L.) Mill. (Chen et al, 2023), Prunus mahaleb L. (Jordano & Godoy, 2000) and P. spinosa L. (Leinemann et al, 2014). It was the latter-mentioned species that attracted our attention due to its wide distribution range and pioneer character.…”