PPP NORDFRUIT – Pre-breeding for Future Challenges in Nordic Fruit and Berries

Dr. Stein Harald Hjeltnes, Graminor, Norway

Plant breeding entities: LUKE, Finland; Graminor, Norway; SLU, Sweden

Academic institutions: NIBIO, Norway; CU-PLEN, Denmark

Associated partners: Estonian university of life sciences, Estonia; Latvia university of Life Sciences, Latvia; Lithuanian Research Centre for Agriculture and forestry, Lithuania

5.7 mill DKK from the Nordic Council of Ministers

Apples and strawberries are the most important species within the fruit and berry production in the Nordic countries. But the Nordic production is insignificant on the global market and our cultivation climate requires adapted varieties with specific characteristics. Therefore, the Nordic fruit and berry breeders have an important task ahead of them when it comes to identifying genes suitable concerning climate, disease resistance and improved fruit quality. The project PPP NORDFRUIT – Pre-breeding for the future challenges in Nordic fruit and berries, has been contributing to this important work – crucial for the future of the Nordic fruit and berry production.

The project has gathered knowledge about fungal diseases and the resistance in the gene pools. This need has increased dramatically due to global warming, consumer awareness and environmental-friendly policies. In apples the main focus has been on European fruit tree canker (Neonectria ditissima) and the storage rots (Neofabraea spp) and (Colletotrichum spp), while the crown rot (Colletotrichum acutatum) was targeted in strawberry. Phenotyping followed a developed standardization for production of inoculum and inoculation protocols. A markedly increased throughput was achieved in resistance screening for strawberry crown rot (Phytophthora cactorum) in a large hydroponic system at LUKE Piikkiö.

Standardization of phenotyping protocols for fruit quality traits were established and five targeted traits were selected in apples panels. These were: Fruit firmness, soluble solids content, titratable acidity, harvest date and average fruit weight. The panels of apples were genotyped by the Illumina 20K apple Infinium. array and the strawberry panels were genotyped by the Axiom Fana SNP 50 k array. The apple genotyping supplemented a comprehensive genotyping with the same array in germplasm at SLU and CU-PLEN, while the strawberry genotyping was unique and included diverse material and a total of 760 accessions were genotyped.

Novel germplasm of strawberries was created by species crossing (F. virginiana x F. chiloensis) provided by NIBIO and planted in fields at Piikki. in Finland by LUKE and at Bjørke in Norway by Graminor. This material has been partly genotyped and phenotyped. Elite populations in strawberries from 4 crosses from LUKE and 4 crosses from Graminor, were rised at Graminor and planted at replicated trials at both locations in 2020 in order to study GxE interactions. These materials will be studied in other projects following PPP NORDFRUIT.

The new knowledge of the genetics has shown relationships between the cultivars and the first association studies have been performed in order to reveal the relations between genotype and phenotype concerning several phenotypic characters. The consortium has gained knowledge on existing QTL markers and identified promising new associations that might be applicable in future breeding.

The collaboration within the project has led to several scientific articles and the Nordic partners of the project has started a one-year follow-up project on apples.

/Stein Harald Hjeltnes, Project Leader NordFruit