Wild progenitor species of strawberry strengthen the genetic base for breeding in Nordic conditions
A doctoral thesis by Attiq ur Rehman from the Natural Resources Institute Finland (Luke) shows that the genetic diversity of wild strawberry species offers great potential for developing cultivated strawberries that are better adapted to Nordic conditions and more resistant to diseases. Modern genomic tools can help identify and utilise these traits more efficiently in future breeding.
The cultivated strawberry is one of the world’s most widely grown berry crops, but production in northern regions such as Finland is challenged by harsh winters, a short growing season and fungal diseases like powdery mildew.
Pre-breeding research supports the development of new varieties by identifying genetic sources of valuable traits. In this study, genetic diversity in strawberries was explored using plant material developed by crossing the two American wild ancestors of the cultivated strawberry – Fragaria chiloensis and Fragaria virginiana.
The material was evaluated for several years in field trials in southwest Finland. The results revealed wide variation in agronomically important traits, including winter survival, plant vigour, flowering time, berry appearance, yield, and resistance to powdery mildew, a major fungal disease affecting strawberry cultivation.
– Wild strawberry species carry a wealth of genetic traits that can be used to improve the resilience and adaptability of cultivated strawberries under changing growth conditions, Rehman explains.
About one-third of the studied plants showed strong resistance to powdery mildew, providing a valuable genetic resource for future breeding work.
Genomic tools enhance breeding efficiency
The study used DNA-based mapping and quantitative genetic methods to identify genomic regions associated with useful traits such as winter hardiness, flowering time and disease resistance. It also tested genomic selection, a method that predicts plant performance based on DNA information.
The results showed that accurate genomic prediction models can be developed even with relatively small datasets, and that including major resistance regions improves the accuracy of these predictions.
– Genomic selection helps identify disease-resistant plants more efficiently, even when the available data are relatively limited, Rehman notes.
The research demonstrates that genetic diversity from wild strawberry species is an important resource for developing more resilient and sustainable cultivars. Combining pre-breeding with modern genomic tools can accelerate the development of varieties that support the future sustainability and competitiveness of berry production in the Nordic region.
Doctoral dissertation on 7 November 2025
M.Sc. Attiq ur Rehman will defend his doctoral dissertation “Implementation of genomic tools in strawberry pre-breeding for Nordic climates” on 7 November 2025 at 13:00 in the Faculty of Agriculture and Forestry of the University of Helsinki.
The public examination will be held at the Forest Sciences Building, Raisio Hall (Lecture Room B2), Latokartanonkaari 7, Helsinki. The event can also be followed remotely.
Professor Hermann Bürstmayr (Institute of Biotechnology in Plant Production, University of Natural Resources and Life Sciences – BOKU, Austria) will serve as the opponent, and Professor Timo Hytönen as the custos.
