Turnip rape - a flexible and hardy oil crop for Sweden

The collection and characterization of turnip rape from a range of national and international sources has resulted in a genetically well-characterized population comprising 188 accessions, providing a valuable resource for future turnip rape breeding.

The turnip rape varieties developed within the Swedish plant breeding program exhibited limited genetic variation, restricting their potential for further improvement through breeding. In contrast, the substantial genetic differences observed between Scandinavian varieties and accessions from Asia, as well as wild and landrace material, represent significant opportunities for broadening the genetic base and enhancing future breeding efforts.

Conventional plant breeding methods, together with field trials, greenhouse experiments, biotron studies, disease resistance screening, and chemical analyses of seed quality, were combined with the development of molecular breeding tools for turnip rape. These included genotyping-by-sequencing (GBS), single nucleotide polymorphism (SNP) markers, genome-wide association studies (GWAS), genomic estimated breeding values (GEBVs), genomic prediction, and transcriptome analysis (RNA sequencing).

Genome-wide association studies identified more than sixty markers associated with eight yield-related traits, including flowering- and maturity time, pod shattering resistance, plant height, thousand-seed weight, and seed yield. Genes controlling flowering time were identified, providing opportunities to increase yield under the long-day conditions characteristic of northern Sweden. In addition, partial resistance to Sclerotinia stem rot was identified through screening of 170 spring turnip rape accessions.

Conclusions

Over the course of five years, the turnip rape project collected and characterized an extensive turnip rape germplasm collection, identified genes and genetic sources for several important traits, and developed a range of new breeding methods and tools to improve the precision and efficiency of spring turnip rape breeding.

These achievements were made possible through successful collaboration between academic researchers and the practical breeding program.

Scaling up the current turnip rape breeding program by implementing the results from the project, that is, introducing modern breeding tools (such as high-precision markers) and methods (genomic selection), would, in the long term, increase the prospects of developing more improved and robust spring turnip rape varieties, particularly for cultivation in northern Sweden.

Outcomes

Practical research training

Several students were involved in the project during its course: Ferdi Agil (Erasmus student from Turkey for 8 months), Inez Falk (BSc student for 6 months), and Mathieu Bernardini (MSc student for 6 months).

Master's thesis

Genomic and Transcriptomic Insights into the Adaptability of Turnip Rape (Brassica rapa subsp. oleifera) av Mathieu Bernardini, University of Grenoble Alpes, Frankrike, (2023).

Publications

Geleta, M., Sundaramoorthy, J., & Carlsson, A. S. (2024). SeqSNP-Based Targeted GBS Provides Insight into the Genetic Relationships among Global Collections of Brassica rapa ssp. oleifera (Turnip Rape). Genes, 15(9), 1187.

Alemu, A., Sundaramoorthy, J., Abreha, K. B., Enyew, M., Geleta, M., & Carlsson, A. S. (2024). Developing genomic tools to assist turnip rape [Brassica rapa (L.) subsp. oleifera (DC.) Metzg.] breeding. Frontiers in Genetics, 15, 1435474.

Continued research

Researchers involved in the project have been awarded funding from other sources for activities related to the project:

Turnip rape breeding for improving resistance to Sclerotinia sclerotiorum. KSLA, SEK 150,000, Kibrom Abreha (2021).

Development of an improved spring turnip rape cultivar with an earliness trait. KSLA, SEK 100,000, Jagadeesh Sundaramoorthy (2021).

Identification of genes and their polymorphisms to combat viral diseases. Formas, SEK 2,983,834. Anders Hafrén, principal applicant; Anders Carlsson, co-applicant (2023).

Projekt members

SLU: Mulatu Geleta, Jagadeesh Sundaramoorthy, Kibrom B. Abreha, Admas Abebe, Shrikant Sharma, Mirela Beganovic, Kaye Bateman, Anders Ekholm, Inez Falk, Ferdi Agil, Mathieu Bernardini, Muluken Enyew

Jerrestad Agro AB: Christer Persson

Hushållningssällskapet Norrbotten Västerbotten: Jan Nilsson, Ibrahem Alkhedr